73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: MuddiGGEr25 on January 26, 2016, 08:51:34 pm
-
MOD/ADMIN: If I put this in the wrong Forum please move it. Thanks!
Ok, everybody im a noob on here, i have been lurking for a while, and i have read probably 400 webpages/forum pages trying to figure out my specific problem but since my vehicle/engine/trans combo is unique/unknown its hard to find a solution, I will try to list everything I can remember that I have tested or already done along with my suspicions that i have not investigated yet due to knee and back injuries, ( i just got out of knee surgery about 10 days ago and the dr allowed me walking and light work) I am a mechanic by day, I also have a mobile shop/Service truck I run from this vehicle as my own business. For background on me, I have attended 4 semesters of Automotive Mechanics in a Community College but no hands on, and i didnt stay long enough to get the Automotive Electronics part. I have been working on various vehicles since I was around 11, but by no means do i know it all or even close, i am always looking to learn more. And I apologize in advance for grammar, or anything i might say to offend someone, I have Asbergers, and ADHD.
Ok first things first; based on the title I have it is the body of a 1988 suburban with a 6.2L N/A originally, no Idea on miles on body. Ok heres where it gets interesting. this was originally purchased by a FD as a rescue rig, they even welded thier own 2" reciever to the front frame (handles a 18K lbs winch) they blew the 6.2L one way or another, now at this point I have 2 stories about the engine that is now in it, on one hand the FD Chief went to a Cali Auction and grabbed up a 5.7L TBI, L05 from a 9C1 police hwy interceptor, OR the other story I have is that the engine was simple pulled from a 1988 suburban from the local impound/auction. In either case I have been told the engine was rebuilt, (no i do not know if it was modified or simple a stock rebuild. I am currently digging deeper into that) they reset the ODO when the replacement engine went in, it currently says a little over 38K nothing is still there from the 6.2L they ran a harness and new relays (im assuming from the donor vehicle) they removed the A/C setup completely i.e condensor in front and in the blower box and sealed it, canister, pump and everything is GONE, i do have a beeline on a 1989 suburban that the engine was robbed from but they left the entire A/C system, compressor and all still sealed with freon. thinking of grabbing that and putting the A/C back in. anyway back to the description, I have also been told by several individuals that the TH350 (yes i am absolutely sure i have checked the pan, and adjusted the shift linkage, bc it used to have the 700R4) was also rebuilt and beefed up including a shift kit, which that i can believe because I have pulled over 6K for 400 miles with 3.42 gearing, and nice firm shifts, even when not towing nice firm secure shifts anywhere between 2K RPM and 5K RPM. Also I do not know why I have a Dual belt setup, i.e. I have a V-Belt to run my PS pump, water pump/fan, but the other side has a (4?) groove V-belt pulley system to run the A/C and ALT, i believe it also runs around the water pump/fan. have not found a stock engine in the parts store computer with the correct alt or compressor, meaning stock with Serp pulley. Also when I first got the suburban I was told it was bucking and spitting above 1/4 throttle because the fuel filter was clogged, would barely stay running at all.
So to recap, 1988 V10 suburban with 6.2L driveline, 5.7L TBI L05, TH350, NP208, Manual Locking hubs, 3.42 AR. 29X9.50R15 MT Radials
So here are the 3 main things I am trying to figure out
A) when I am applying "Light" throttle, i.e in 2nd or 3rd gear in town 25-35mph on a flat grade it, almost seems like the timing is retarding because it seems to bog and cant get out of its own way, does not do it when coasting, and stops it/returns to normal if i go to about 20%-25% throttle.
B) It has been doing this since i got it, If i leave it in 1st gear and apply no less than ~20% throttle, but no more than ~40% throttle, right at 25MPH/2500RPM (yes with my tires and gearing in 1st gear my MPHx100=RPM) it takes off without any change in throttle position, i mean it puts you back in the seat a bit, then returns to "normal" at 35mph/3500RPM will also do this in 2nd gear if i am off road/drifting/horseplaying. I can make it do it as many times as i want, always the same speed everytime, and if i put too much into the throttle it will not do it.
C) I am trying to get my kickdown cable (yes kickdown cable not kickdown rod, or TV cable, several people have tried to correct me) to obtain the correct tension at WOT, and idle, they way i have it now, it is taught at WOT but has slack at idle, I cant seem to get the best of both, im not sure if my arm radius is wrong and i need an adapter maybe?
I HAVE done the following all within the last 3 months for sure:
TPS: tested ok, but replaced it with a known working one, and tested that one before install
Igntion Coil= tested good, tried a brand new one, no change in behavior so i returned it.
MAF sensor= tested, but replaced with a known good one
ICM was seting a code recently and the bogging at light throttle was unbearable almost couldnt reach 20mph, I went to the yard and got 2 genuine GM ICM's the one I took out was a 369, so i replaced it with the 369 i found and kept the (048??) as a spare, I already know about the table differences contained within these two chips. This returned the engine to a manageable state, this was 11 days ago.
Plugs, Wires, Cap, Rotor were all changed together
Alt was failing when I bought the Burb. went to Carquest got REMAN, 78A 10SI since it was covered under a lifetime warranty. this was roughly a month ago.
Fuel Filter- changed the 2nd day I owned it because I could not get into the throttle more than 15% or it would start kicking/bucking/spitting/cuttng out it was really horrible. however this had no effect on anything.
Fuel Pump- As the light throttle problem got worse and i also started to notice I was slowing down when racing even though I should have ample power since the air up here has been 0 to -20F the last week, I hooked up a snap on FP guage, digital, FP was 11.5 when it primed, down to i think 8.5 when power braking in 4WD, and flooring it in 1st, and it sounded horrible too. I had a TBI pump around that was given to me months ago, I used to bypass my mech pump on my 77 ford when it failed 300 miles from home, it ran a 450HP engine with plenty to spare, I have not actually gotten a PSI reading yet due to my surgery but I can attest the Performance has GREATLY improved, and starting is slightly easier, however still takes 1-5 seconds to fire up. this was done the day before my surgery.
PVC Valve- I tested it and it failed my "shake test" so replaced it, this also slight improved idle and overall response.
Vacuum leaks- none that can be found with a unlit propane torch OR BrakeKleen
EGR, is functional however it starts to run ****ty at part throttle with it hooked up, so i bypassed it, and no the ECM has not set a code for it, even with multiple hwy runs 100 +miles each way. not sure why.
0W20 Mobil 1 Oil Change/Mobil1 w/ 1qt Lucas Syn Oil Stabilizer ( yes i can attest to it working, slightly lower oil temps, and a slight decrease in 0-60 times) extended filter. maybe 2200mi on so far
Air filter has been replaced with a 3" ( i think) open filter, set on top of the TBI in a "chrome" housing lol
AntiFreeze strength was increased to 70/30 for the constand subzero temps up here.
ECT tests good, and shows the proper temp F and has a very steady and gradual inscrease while engine is warming up ( my day shop has a very nice expensive snap on scanner that allows connection to anything with a computer port)
Injector pulse test- I have videos showing the pulse testers installed in place of the injector, pulses are as expected, however, as you can see if you want to in the videos, it barely runs on 1 injector, however when i swap sides it starts once, then refused to start up and idle, had to reconnect both injectors and crank crank and floor it, then it started up.
I have run lucas and Howes fuel injector system cleaner many many tankfuls, and B12 Chemtool spray to clean the throttle blades.
IAC valve, tested fine but replaced it with a know good one, no effect that i could notice
Timing, when I thought the timing was off, I grabbed snap on timing gun, finally found the ECT disconnect, and set the base timing, It was wayyyy advanced based on the stock balancer marking, but i experienced no PING however most fill ups I get 91 with NO ethanol. Reset the base timing to about 2 DEG BTDC, then hooked it back up and restarted it, I say "about" because the timing mark bounces around between 0-2 D BTDC even with it hooked back up the timing wiggles, but i checked the DIST, its exteremly clean might be reman too, but no slop in the shaft. Now that i think about it I might have set the timing wrong -doh- I think i hooked the timing light to the wire coming out of the coil and not the #1 -.- stop the water ill have to check on monday after work'
I have cleaned EVERY ground, from frame to block, block to firewall, bat to block, bat to front panel, front panel to headlights, and a few aftermarket grounds I found also
Have not done the following:
I think i grabbed a extra Spark Control Module (next to the MAF) but unknown how to test it
Test the current FP
Test the Injectors themselves (when i had the timing light shining down the TBI, I could not see the fuel spray pattern whatsoever)
Check the FPR spring/assembly since I do not know how to dissasemble it yet
Intended upgrades that may pertain to these problems/solutions
LS1 High Pressure FP upgrade
FPR 15PSI spring upgrade
Certified Rebuilt 9C1 police flow matched injectors W/warranty and good reviews
CS130/CS144 Alt upgrade because the 78A model cannot maintain the aftermarket stereo/amp/additional running lights, 2 driving lights, and 4 OR lights + the rear fan.
Might get a better aftermarket Igntion coil since this burb will be playing around at Trucks Gone Wild in June & maybe september, and I enter most of the local mud bogs.
Pertaining to performance and fuel economy, before the fuel pump change i was getting 4-6mpg in town and you could forget about even trying the hwy. before the pump started acting up I started with 11-13 in town and 15-19hwy, gradually decreasing to 8hwy regardless of going 55 or 85 (yes i tested it on 3 separate trips on the same 200 mile drive however during all 3 runs I was using 87/10% corn) There is a very noticeable difference in running the 87/10% corn vs 87/ no corn vs 91/no corn, I even see an average 2mpg increase in hwy towing or not. And with 91/no corn I have very noticeable better throttle response and much easier to climb big hills when towing our camper. For example I have to downshift to 2nd when towing the camper up steep grades @55mph when using 87/10% however when i fill with 91/no corn I can stay in 3rd all the way up same hill same ambient temps and same load.
PS I also have this same post on 2 other web forums trying to get help quickly:
http://www.chevytalk.org/fusionbb/showtopic.php?tid/332480/
http://67-72chevytrucks.com/vboard/showthread.php?p=7462440
https://www.youtube.com/watch?v=LgBRy81rujE
https://www.youtube.com/watch?v=sK62a75IZ0Q
Those 2 are videos of the data readouts 0-6000rpm and power braking (yes i know one is labeled wrong)
The next 2 are the timing with the ETC connector disconnected and with it connected, I could not hold the camera and the light and operate the throttle all at the same time but i did watch it advance a bit while the camera was off. this is just the camera built into my phone and i think there might have been some grease on the lense that I couldn't get off. Let me know what you think.
PS I left the timing right where it sat bc i believe that to be 0 BTDC or very close.
https://www.youtube.com/watch?v=OVSCI39k2BU
https://www.youtube.com/watch?v=nxZuWsY6sbI
I can upload Pics if needed in the AM when its sunny out
-
Compression check? Your higher RPM's can give you the false pretense that you have great compression. Not always the case. May be why your issues are at low RPM's. Just happened to me. Purr like a kitten at 75 MPH, dang near die at an idol. #7 was a dead cylinder.
Have you recently done a Fuel Pump Pressure and Regulator Test?
Sounds like you added a lot of clean er' out chemicals, could be cuttin yrs. of varnish in the tank.....Maybe? May want to change your fuel filter again, see whats in it. If its nasty already, you might think about dropping and flush the gas tank.
Years ago, I had a similar issue w/a 240Z, thinking I was cleaning out. After the 3rd. FF inside a month, a buddy convinced me to drop the tank, looked like puke cottage cheeze type texture coming off the bottom.
-
Compression check? Your higher RPM's can give you the false pretense that you have great compression. Not always the case. May be why your issues are at low RPM's. Just happened to me. Purr like a kitten at 75 MPH, dang near die at an idol. #7 was a dead cylinder.
Have not checked compression was thinking of doing that this week before friday if i have time at the shop, but doesnt run rough or miss, and has massive tq in low band, I can reach the 6000 mark in 1st 4HI and in all 3 gears in 4LO, I can pull 3-5K lbs with no effort, I only have the hesitation when I am "barely" off idle just maintaining 25-40mph, so around 5-10% throttle at most, if i go past that point it just goes back to normal, but it is no necissarily at low RPM, it can be doing it in 1st,2nd or 3rd, at any given speed when i am attempting to "cruise"at that speed,but is more noticable at city speeds
Have you recently done a Fuel Pump Pressure and Regulator Test?
I did do a FP test BEFORE I changed the pump, it was around 11.5 at idle and dropped to 8.5-9.5 when WOT, and powerbraking, so i changed with a known good pump and strainer but have not had time to check actual reading but it has improved greatly since the replacement pump went in.
Sounds like you added a lot of clean er' out chemicals, could be cuttin yrs. of varnish in the tank.....Maybe? May want to change your fuel filter again, see whats in it. If its nasty already, you might think about dropping and flush the gas tank.
I dont seem to be having a fuel delivery problem but the fuel tank looked very nice inside, it seems when they did the engine swap they cleaned the tank before installing it. but I get plenty of fuel when pulling a load up hillin 3rd which i believe would demand the most of the fuel pump
Years ago, I had a similar issue w/a 240Z, thinking I was cleaning out. After the 3rd. FF inside a month, a buddy convinced me to drop the tank, looked like puke cottage cheeze type texture coming off the bottom.
Also not sure why it would be having compression issues at only 39K miles after a rebuild, I mean yeah i know anything is possible but everyone i have spoken too that used or owned this truck after the rebuilt said it was babied and only taken out for hunting, and an occasional tow.
https://www.youtube.com/watch?v=Ep397imVhWA
Video of injector spray pattern and Vac reading at idle after short drive <2 miles
i know the guage is dirty but its sitting between 20-25 and my gauge reads around 2 because its not zero-d anymore, but its the only gauge I have access to ATM
-
My first shot would be the ESC. And there is a procedure for testing it which I will post however I would first start by simply unplugging the knock sensor wire, tie out of the way and take a spirited drive. Then try one of these. ..
(http://i1290.photobucket.com/albums/b527/frotosride1/Screenshot_2016-01-27-20-15-06_zpsvg4hwgrc.png) (http://s1290.photobucket.com/user/frotosride1/media/Screenshot_2016-01-27-20-15-06_zpsvg4hwgrc.png.html)
(http://i1290.photobucket.com/albums/b527/frotosride1/Screenshot_2016-01-27-20-16-14_zpslr8dbljs.png) (http://s1290.photobucket.com/user/frotosride1/media/Screenshot_2016-01-27-20-16-14_zpslr8dbljs.png.html)
(http://i1290.photobucket.com/albums/b527/frotosride1/Mobile%20Uploads/Screenshot_2016-01-27-20-30-11_zpscynobanw.png) (http://s1290.photobucket.com/user/frotosride1/media/Mobile%20Uploads/Screenshot_2016-01-27-20-30-11_zpscynobanw.png.html)
(http://i1290.photobucket.com/albums/b527/frotosride1/Mobile%20Uploads/Screenshot_2016-01-27-20-30-11_zpscynobanw.png) (http://s1290.photobucket.com/user/frotosride1/media/Mobile%20Uploads/Screenshot_2016-01-27-20-30-11_zpscynobanw.png.html)
-
(http://i1290.photobucket.com/albums/b527/frotosride1/Mobile%20Uploads/Screenshot_2016-01-27-20-30-01_zpsydpuzwhj.png) (http://s1290.photobucket.com/user/frotosride1/media/Mobile%20Uploads/Screenshot_2016-01-27-20-30-01_zpsydpuzwhj.png.html)
-
I just want to say that sometimes less is more... :o
MAF sensor= tested, but replaced with a known good one
You mean MAP Sensor?
Have you tried unhooking the vacuum hose to the EGR valve to see if it makes a difference?
-
(http://i1290.photobucket.com/albums/b527/frotosride1/Mobile%20Uploads/Screenshot_2016-01-27-20-30-01_zpsydpuzwhj.png) (http://s1290.photobucket.com/user/frotosride1/media/Mobile%20Uploads/Screenshot_2016-01-27-20-30-01_zpsydpuzwhj.png.html)
Thanks for all that info, I will see if i can get to the knock sensor before we make an errand run a little later today, so as long as its not recieving a signal from the knock sensor, then it should not retard any timing based off this circuit? after my drive later i will get back on and see if it changed anything I love having data sheets :D
I just want to say that sometimes less is more... :o
MAF sensor= tested, but replaced with a known good one
You mean MAP Sensor?
Yes indeed i meant MAP, I was very very very tired when I wrote this
Have you tried unhooking the vacuum hose to the EGR valve to see if it makes a difference?
I thought I had put in in this forum, but i probably did not, the EGR circuit is completely bypassed for the time being, it is operational however makes the engine run very rough and undrivable when it does open, it was disconnected when i got the burb but thought i would try it out and after no luck on that front as to why it would run so bad when it opens up i just bypassed it all and called it a day, i know of plenty of TBI trucks/vans and even an RV that had or have the EGR bypassed and they drove and towed for many years that way.
-
Sorry everybody, went out to run to the food pantry and the starter solenoid gave up the ghost, its been acting funky for weeks, sometimes not letting go of the flywheel, or making a clunk sound as it disengages. but grabbed a NAPA reman through work at cost $30 i think :D and now its installed and the truck will start but dont have a reason to go drive now, but i have several trips tomorrow atleast 2 are at hwy speeds out to the hosptial/clinic for the father in law, so i will keep a good eye/ear on it and listen/feel for improvements or lack thereof and give an update. on a side note i think my SES light is burnt out now, it dont come on when I key it up before starting it.
-
Ok for anyone who wants to know or think this might be useful, My starter went out on me yesterday and I swapped it with a NAPA 1.4kW unit, turns over nicely now,and i think its not as draining on the battery, I also disconnected the knock sensor and, I couldnt tell you for sure if its running any better performance wise however I have tried to get the "turbo" imitation to repeat at 2500RPM and now it wont do it, I have done nothing else so far besides starter, bat disconnected for about 30 minutes, and unhook the knock sensor, I have to pickup the mrs from work around midnight so i will slide under and reconnect it and see if the fake "turbo" happens again. The scanner showed it was running lean according to 02 data, so im almost thinking that my replacement fuel pump might be weak also, I will obtain PSI numbers later next week, however for the time being, Would a lean condition lend itself to more knock counts? and therefore affect the timing? next I guess i have to find out if i do have a lean condition and if so why, I will be increasing pressure to the injectors to about 15-18PSI so I should be able to richen the mix in a month or so, could having the EGR disconnected cause this also? since it only happens at part throttle, not idle or WOT, and if i do need to reconnect it, What would be causing it to run like crap as the EGR opens?
I may begin another thread once I have the axles/springs dismounted tomorrow morning, but I found this K20 in the yard and its the only 3/4 i found with both still in it, now from what I have found it should have either a SF or FF14 in the rear since it is a 1982 with the 6.2L, 4.10 AR and a 10 bolt front with 8 lug shafts.
Does anyone see why or why not this will work? I have not measured the springs end to end yet since i didnt have a tape with me, but otherwise should the shocks/axles/ yokes line up? There is a older 1/2 burb i got the RPO codes for in case the 3/4 doesnt work out, but the 3/4 stuff would be better for towing and playing.
-
whats left of the manual/options
-
the donor truck hopefully
-
Have you checked the fuel integrator and block learn?
Have you checked the TBI base gasket?
Have you checked the firing order?
-
Have you checked the fuel integrator and block learn?
how would i go about checking this? using the scantool?
Have you checked the TBI base gasket?
yes the gasket is fine and no other vacuum leaks that can be found with brakleen or propane
Have you checked the firing order?
yes firing order is correct
-
yes using a scanner or scan software on a laptop and a cable
-
just like in this video: https://www.youtube.com/watch?v=LgBRy81rujE
My Integratr and block learn are always at 128 when i scan it/live data feed, i know for a fact that these numbers have not changed ever and i have had the battery disconnected or dead more than 20 times and i have used the scanner atleast 10 times since i got the burb and it struck me as odd that they didnt change at all, but i thought maybe once it sets a value it stays the same, or maybe they flashed it when they had it rebuilt, (still working on paperwork) but i know good and dang well it isnt a stock 87 block, everyone i talk to and the couple threads i have found on it, say that the 87 sbc, since mine has the alt/smog on pass side and ps and a/c drivers, factory its redline was around 4200 or 4500 depending on who i ask, but now that i say this I cannot find the 2 forum pages i finally found it on last time, Anyway I pull really good to 4300-4500, then it starts to decline but can reach 6000 without effort at 6200lbs 3.42 axle up a nice hill, but i suspect thats also due to my "lean" condition and its source.
-
Have you tried unplugging the tcc solenoid and seeing what happens?
-
I dont have a locking TC, unless your referring to something else, I have a beefed up TH350, but i didnt get the lockup kind :(
-
Sorry, and no offense but I didn't read the whole book.
Have you checked your exhaust back pressure? Is there a catalytic converter in place? Stock manifolds, single exhaust?
-
Sorry, and no offense but I didn't read the whole book.
its all good lol i didnt mean to come off offended im just really tired lol
Have you checked your exhaust back pressure? Is there a catalytic converter in place? Stock manifolds, single exhaust?
no cat, custom (from the date of engine swap) true duals but no H pipe which i think i will add later on, ive heard it runs a bit better with it, 2 oversized mufflers and one isnt very tight so that side has an exhaust leak, and both pipes are loose right where they come off the collector bc i tried to tighten them and i broke a bolt on each, but its not a bad leak.
-
exhaust leak is far enough downstream to avoid interfering with O2?
-
exhaust leak is far enough downstream to avoid interfering with O2?
yes many many feet past the 02 sensor, but i had this issue before i tried tightening the exhaust also.
-
If you are mechanically sound and verified, have no faulty inputs then what would your conclusion be?
-
If you are mechanically sound and verified, have no faulty inputs then what would your conclusion be?
Personally logic is pointing me towards either timing not working correctly for the engine build, or I still do not have enough fuel delivery, which i cannot verify either until later next week. I was getting alot of knock readings in that video i posted on youtube, but that could be a faulty knock sensor or a lot of real knock, but if i am getting knock because of a lean condition then I would have to make sure the FP is proper again, but also I am suspicious of one of my injectors because when i pulled them one at a time and put a NOID light instead, one injector was able to keep the engine running while the other injector could not when it was its turn for the test. I am fairly confident the timing advance components are all functioning properly, my input sensors have been tested and verified so i dont believe it is a sensor fault, with the exception of maybe the knock sensor, but I am not sure if a custom rebuild would have changed the "sounds" the knock sensor listens for and could be setting a false positive??? this is something i am not knowledgeable about. I just ask on here because I am not familiar with chevy tbi too well, and dont really have the ability to chase leads that might take me nowhere, since i only get a couple hours before my back or knees act up and i have to call it quits for the day. I noticed during my drive earlier it almost seemed to sound like it wanted more fuel but wasnt getting it, it makes me wonder if the rebuild requires more FP or volume to accomplish its full powerband. I just want to get as close to 100% as possible before feb9th after that I will be upgrading the regulator spring and Fuel pump for sure, and maybe the injectors if i can squeeze it. I wish i had paid more attention to the TBI my uncle used to drive.
My next steps would be
FP test again
maybe find another used injector or 2 at the yard tomorrow if i have time
try another knock sensor?
-
Custom rebuild? Any chance you have a gear drive timing set. This can very easily simulate knock and specifically says on most packaging and instalation instructions "not for EFI" and or ESP controlled vehicles.
-
Custom rebuild? Any chance you have a gear drive timing set. This can very easily simulate knock and specifically says on most packaging and instalation instructions "not for EFI" and or ESP controlled vehicles.
I would assume they were smarter than that, however I have 0 details on rebuild so far, waiting on a couple people that went hunting in this rig years back to see if i can backtrace the papertrail.
-
Update to original Topic:
I disconnected the knock sensor the same day my starter failed, it has been disconnected since then.
I feel underpowered, like it seems to drag itself along from 3500-6000rpm, but idle to 3500 seems pretty normal.
I can NOT get it to repeat the "turbo" effect from 2500-3500rpm, I have been trying for several days but to no avail.
I think my CEL is burnt out because it does not light up when KOEO, and it hasnt lit up since the knock sensor was unhooked. I have not connected a scanner yet to see if I do infact have a code.
I can currently cruise without it feeling like it wants to fall on itself 25-40mph.
also IMO i think the idle is high, but no vac leaks, ive even tried plugging all the ports with rubber plugs to eliminate possibilities. it sits around 900-1100 at idle, and even when up to 180F im still in the 900's.
I have seen a noticable in town MPG increase (1-3MPG) cannot give exact # because I havent refilled yet, but the tank is lasting longer, and I am not being any nicer to the throttle, I even went mudding a few days ago, and raced a jeep yesterday.
I am going to reconnect it later tonight and drive a couple days and see if the symptoms return.
I am wondering since the starter is right there, could the starter have been causing a false knock reading as it rattled around? it was pretty shot.
Also I am beginnning to suspect my used pump is getting tired, as I am almost always reading a lean condition, and I know a lean condition can lead to higher knock counts as well, I will get some free time towards the end of the week and test the FP again and see what i get. I am only wondering because it almost acts like its lean, and when i romp on it, it sounds like its sucking way too much air in comparison to the fuel coming in.
However what should be my next suspect if my knock counts remain high but my FP is actually ok? No VAC leaks, only minimal exhaust leaks, (less than 1/8th here and there) base timing is correct.
I have to tow a 25ft RV in a little over a week, so i need to be running as close to 100% as possible.
-
pinch off the return line on the rubber fuel hose.
-
pinch off the return line on the rubber fuel hose.
I havent had it up in the air in a while, where does the steel go into rubber? is it up near the firewall, or above the tank?
-
over the tank or up by the bellhousing. That line is steel braided so you will crush it. Go near the tank and pinch it off with needle nose vice grips.
-
sorry for the absence, I lost this thread in the 100+ bookmarks on this project.
I did get the 3/4 front and rear axles and spring packs installed (that has its own thread),
We did tow the RV home, it was 280ish miles each way, and 3,000lbs for the empty trailer on the way down, and 10,000+ with the motorhome on it.
We managed 55MPH average on the way back sitting over 13ft tall and 10,000lbs of trailer, and over 8,000lbs lbs of burb. we did 65-70 on the way down but had vibrations over 60mph because my ujoint straps were bent and cracked and i only had 2 bolts holding the driveshaft on, but it was too fricken cold and snowing to bother with it unless it broke, which I had the parts with me if it did, however this was remedied about 3 days ago because it was warm enough to crawl on the ground.
Learned that my peak TQ as the TBI runs right now is 3700RPM I figured this out, when towing an RV on a deckover trailer weighing over 10,000lbs up a very very steep hill, well over a mile long, 3rd gear just couldn't keep me at 55MPH so I dropped to 2nd, throttle maybe 40-45% and although I couldn't go over 55MPH/3700RPM, there was more than enough TQ there to maintain it with ease. And cliffy was over 8,000lbs with full tank, almost every single tool I own and air compressor too.
Currently 4.10 Rear axle ratio, but if i get these 35's it will be 3.71, so we will see if that helps or makes it worse.
I am getting 10.8 mpg at 55mph with a good crosswind, and 6.9mpg doing 70-80 with no wind. the TBI is still sluggish at WOT when I need it most, but up to 75%ish throttle i have EXCELLENT response and power. So i am going to find that rubber line tomorrow and see if symptoms improve, if not ill actually bust out the FP guage at work on monday and see if i put a bad pump in. long term goal was TBI pressure increase to 17psi, but i might be getting a 454 4bbl to put in cliffy later this month, and the 5.7L will go into the 81 motorhome, so I still need to figure this out, but once it goes into the RV it will have a inline adjustable FP, running off the ignition and oil circuits. so fuel delivery will not be a problem. and I will probably just regulate the TBI pump down to the 8-10PSI the BBC wants, I had a similar setup in my 77 RV when i got it.
I will also pull a plug or two tomorrow and see how they look. I sprayed throttle cleaner all over the engine, intake, every vac line, and no change in idle whatsoever, but my $12 tach says i'm idling at 850 in P and N, and R, D,2,1 I drop to 500-600. So i dont know whether to believe the SNAPON scan tool or the tach, the tach is showing accurate readings on the HWY when i punch them into a gear ratio calculator.
swapped a 150A 1 wire alt on, however the OEM 6" bolt snapped in the middle of SD at 1AM so I currently have a tiedown pulling the ALT tight until I can get the broken bit out of the block, which includes removing the fan and shroud.
based on crazy knock counts still, and the poor WOT performance im going to gander my issue is a fuel issue, add on that im always running lean according to the scan tool, AND im running 200F. But if i increase my fuel being delivered, im not sure im gonna like the MPG results lol, I might like the power though
Brake stall is 1500RPM, but does not overpower the brakes, flash stall comes very close to the same.
-
It's normal to drop rpm going into a gear, maybe not that low, but 200rpm difference isn't necessarily a bad thing, you can try upping idle in park to 950, and see what that does
Sent from my Lenovo TAB 2 A10-70F using Tapatalk
-
I know idle drop is normal, but the PCM is saying im at 1000-1150, but the tach says 850 almost exactly, and when i drop in gear i go as low as 400 or as high as 600ish, usually i dont drop that low unless its a lopey cam.
I dont have an idle adjustment on the TBI, or atleast not that i can access.
-
I have and have always had the same issue. Before I changes my IAC and reset the value the truck would die on me every so often when shifting into gear from park or R-D, I didn't have a tach then but after using my cheap one for the last 4 months b4 I put it on the run stand (which I originally purchased it for) I know my idle in gear is between 550-600 max. But no more stalling!
(1000posts)
Based on your earlier discriptions it sounds like you have a true '87 accessory drive so it's likely you just have a slight reman keeping within factory specs.
I currently have 35's and 3.73's it's ok but I feel like the engine would appreciate a taller gear at times. My shift points are all below 5k I'd say between 46-4800 at best. This is with all OEM running gear minus a few small engine bolt ons.
-
The PCM'S rpm readings intrigue me because when I shift into reverse or drive it often feels like I'm shifting from that rpm but according to the tach it's more like 900-1k then a drop to around 550-600
-
There is an idle adjustment but it is capped off for a resone. If you have reset your IAC and have no stalling issues then I wouldn't bother with it but if you are intrest ed in the name of science... it is behind the plug on the driver's side just inboard of the throttle blade shaft. Drill a hole and get a #15 or #20 torques bit and pay attention to how much you turn it. I really wouldn't recommend adjusting it unless you are trying to test what the ECM is seeing.
-
I have and have always had the same issue. Before I changes my IAC and reset the value the truck would die on me every so often when shifting into gear from park or R-D, I didn't have a tach then but after using my cheap one for the last 4 months b4 I put it on the run stand (which I originally purchased it for) I know my idle in gear is between 550-600 max. But no more stalling!
Based on your earlier discriptions it sounds like you have a true '87 accessory drive so it's likely you just have a slight reman keeping within factory specs.
I currently have 35's and 3.73's it's ok but I feel like the engine would appreciate a taller gear at times. My shift points are all below 5k I'd say between 46-4800 at best. This is with all OEM running gear minus a few small engine bolt ons.
I have changed my IAC with a known good one off a 1ton van with no NO idle or running issues
I havent had the pleasure of stalling lol. is yours a 87 350 also? I havent been able to find the forum posts again, but i read on 2 different ones, where a few people said redline on the 87 block OEM was like 4800. then increased after some design changes that year.
I am now running 4.10 8 lug axles with oem tire height for now, i have noticed a small increase in mpg over the old 3.42 6 lug. but my effective ratio will be 3.71 if I buy the 35's.
Even towing 10,000K+ with the 5.7L it was not lacking the low band at all, I could get through each gear relatively quickly. mind you i am comparing to a mid 90's K2500 with the 6.2L turbo, a early 90's Chevy 3500 minidump truck with 6.2L turbo, and a 2000's 2500HD with the larger gas engine (i dont recall it right now)
I can pull an equal or identical load just as well as the diesels and better than the gas, (but the gasser had sensor issues), I am talking everyday pulling, 2,000-4,500lbs of lawn and snow equipment for 8-16 hours per day.
I am just barely slower (about 8-10ft) than a mid 90's tahoe with a slightly modded 5.7L vortec, 3.73 AR, about 1,500lbs lighter, and steeper 1st gear. that was with the 3.42 vs her 3.73 AND higher 1st gear. now with the 4.10, im pretty sure i could creep past.
I would like to verify stock OEM 87 engine specs but i am having no luck locating any info specific to the 87 block and its specs, or the pulley arrangement for the A/C
And no im not worried about the adjustment,and now that you described it i think i have read about it before, but my memory only lasts about 1-2 weeks, otherwise i cant remember without a trigger.
If you go up to my youtube links, i have many videos of the PCM readouts
-
what i did find on gmtuner.com was this
body CR HP TQ
1987 V8-350 F 8 Tuned Port FI 9.0 225 @ 4400 300 @ 2800
1987 V8-350 Y 8 Tuned Port FI 9.5 240 @ 4000 345 @ 3200
1987-up 350's had hydraulic roller lifters, new design centerbolt cylinder heads, and one-piece rear main seal cranks.
and this on full size chevy:
I have a 1986, 350 from a 3/4 ton in my 74. These engines from the early mid 80's 3/4 ton and 1-ton have a real truck cam in them. Shift at 4800-5200. It loses power at higher rpms and is very noticable at 5200 and above. However the engine should rev to 5500-5600 safely if its in good shape.
So i really really dont know what to believe and no papers on the engine, dont even know what shop did it, but according to the gm tuners page, my TQ "Stock" should stop 2800 or 3200 RPM, but i know mine isnt done till 3700ish, hardly any slippage at the TC either, its really tight
PS I meant 6.5L turbo NOT 6.2L sorry i drove about 8 hours today on maybe 5 hours sleep, and loaded and unloaded 2 axles and 6 tires, and tools bymyself, from the ground to my tailgate like 3ft up with no leverage -.- so i am like out of it right now lol
just googled the specs on the 6.5L we had in 2 of the work trucks for comparison. the 3500 had a 4.56 rear according to the glovebox, and im 99% the k2500 had 4.10 when i had the papers around in the shop. so similar weight "empty" similar ratios, and similar tires, the 3500 had the nv4500, and the k2500 had 4spd auto.
Engine Weight:
Roughly 750 lbs
Max Engine Speed:
3,400 rpm
Peak Horsepower:
Introduced at 180 hp @ 3,400 rpm. Offered as high as 215 hp @ 3,200 rpm.
Peak Torque:
Introduced at 360 lb-ft @ 1,700 rpm. Offered as high as 440 lb-ft @ 1,800 rpm.
i know im kinda comparing apples to oranges, but at the same time, highway or city, I could do the same load just as easily with my 87' 5.7L TBI as the 5.7L, no my hitch or total weight capacity was not the same, nor do i have the O/D but we "Raced" a couple times with trailers attached because my boss was adamant that his 6.5l was superior, we loaded the exact same equipment onto 2 almost identical trailers, about 4,000lbs behind us each, again approximate, it was a couple 0turn mowers, and concrete. He had me in 1st gear by about an entire length, but then he went 2nd and I was still in first and gaining, then i shifted to 2nd and overtook him. then in 3rd we were neck n neck. we also raced on a dirt road all 3 of us empty, his k2500, the other guy had his 1500
(dodge i think) and mine, we held neck and neck 4x4 for 3 miles at 95mph, none of us could safely go faster on that road, way too many bumps and loose gravel. but nobody won that day. I never let them live it down that a 87/88 suburban kept up with his K2500 diesel and his buddies 2014 1500. nevermind that i weigh alittle more lol. oh and that dirt road race was with the 3.42 GM10 6 lug axles.
-
Oh, and 3700rpm peak tq on 87 no ethanol gas, i dont run ethanol because i notice a significant power and mpg loss, also I get an extra 1-3mpg running 91 with no ethanol, and noticeably more power under the "pedal" lol but sometimes the per gallon cost isnt worth the higher octane. but since i do get an improvement using the 91, im wondering if my CR isnt increased over stock?
-
I made a new thread about my most recent discovery since this thread is and isnt on track with what i discovered. and i wanted a clean slate for the diagnosis for future and current members in case they run into the same issue. however I will copy and paste here what I discovered while reviewing my video logs and reading ALOT on programming the PCM, and about the BLM and INT readings, and open/closed loop etc.
:Ok, so i think i figured out my issues after reading hundreds of more pages regarding the Integrator and BLM values, and yada, yada, then I went back to my recorded video of the live data output on the shop snap on scanner. i noticed the 02 only really varies 430-451mv, it is always in open loop even at 208F, the knock counts are ridiculous. my BLM and INT both stay at 128, which from what i have read is caused by the O2 not letting the PCM head into closed loop. my MAP was saying 8-9in but my manual gauge is reading double that, i cant believe i didnt see that before.I know at some point in the last 2-3 weeks i did find a sizeable vac leak and sealed it, but I dont remember when, and it didnt affect performance so i didnt mention it. Nonetheless, I am gonna try to find my other MAP I had extra around and then record the data readout again on monday after i punch out. But before I start on my data recording on monday:
1. Is it true that it cannot enter closed loop without the O2 sensor reaching a preset temp/mv reading? its not original exhaust and it is very possible that the sensor is cooled off by that point. I will check sunday afternoon to see if it is a lazy O2 or wideband. i thought i saw 3 wires but cant remember.
2. VSS input, the PCM/ECM whatever you want to call it, its got a spot for it, did the 700R4 in 1987 have a VSS for the ECM? and if so will that control the open/closed loop at all? and even if it does not, can I get a VSS module for my TH350 and eventually change out my dash with all digital speedo & gauges?
3. After I get it to enter closed loop, the A/F learned should switch to YES, and my knock counts should be completely or almost gone after it "learns" the block correct?
4. If all above are corrected, then I should get 100% performance back from the PCM after a few drives? assuming my used pump is in fact good.
-
I'm not sure exactly how the o2 sensor plays into closed loop but I do know that anything above 160* should be closed loop. Also the location of your o2 sensor will pay a huge part in its MV reading. It should be @ 600* to function properly and if it isn't high enough in the exhaust it will not reach temp and cause a 470 (ish)MV reading.
I would check the o2 temp to justify the MV readings you are seeing
2. There is a VSS sensor in the trucks with 7700r4's but they are mostly located in the dash. Behind the speedo there's an optical sensor that reads a reluctor ring which is attached to the speedo.
3.
-
I'm not sure exactly how the o2 sensor plays into closed loop but I do know that anything above 160* should be closed loop. Also the location of your o2 sensor will pay a huge part in its MV reading. It should be @ 600* to function properly and if it isn't high enough in the exhaust it will not reach temp and cause a 470 (ish)MV reading.
I would check the o2 temp to justify the MV readings you are seeing
2. There is a VSS sensor in the trucks with 7700r4's but they are mostly located in the dash. Behind the speedo there's an optical sensor that reads a reluctor ring which is attached to the speedo.
3.
I have read on the GMtuners and a couple other knowledgable sources that until the o2 reaches said temp then the computer cannot enter closed loop and i have read many posts of indivuals confirming the same.
I checked the physical o2 sensor and there are no wires in it at all anymore, and the only connector near enough is a 4 plug with 3 wires in it. I thought it might be a "custom" heated o2 connection that was installed during engine swap. but the colors dont make sense for a o2 sensor.
and the wires for the aformentioned connector have melted to the exhaust so i would have to replace them anyway
There is no single wire anywhere nearby that could be the existing o2 wire and this forum: http://67-72chevytrucks.com/vboard/showthread.php?t=352321
it says i need to find the purple D7 wire for the sensor wire for the 02 on a 1987 harness, and since my block is obviously an 87 it would make sense if they in fact pulled everything from 1 donor.
I was wondering if getting a VSS adaptor for the TH350 if that would help the engine at all.
I also have code for open/short/faulty o2 but im getting mid 400mv up to mid 500mv readings and i dont understand how that is possible with nothing connected
-
O2 temp is definitely a doctor but having it connected to the ECM is the first step...jk!
The VSS signal is paramount for any computer controlled vehicle. The ECM uses it to adjust fuel and spark tables. You will never get it to run right without a VSS signal with the right pulse. Check behind the cluster BC a gage swap would have been easy for them to do and you wouldn't know it was there without taking out the guage panel. But I do believe it's a 4k pulse so an adapter connected to the VSS input is a good idea.
Fix the O2 first of course. I wouldn't imagine a complete swap and them leaving out the VSS wire
-
Well they went from 6.2l and 700r4 which i thoight i read somewhere that it had electronic speedo and a vss in the trams somewhere amd now its the 5.7l and th350 which i know is mechanical lol. O2 will be in just as soon as i find the signal wire and have time to bust the old one out lol
-
Ok so did some more work and i installed a used 4wire narrowband heated o2 sensor from a 98 pontiac, that was working at time of pull (about 2 months ago)
I got my info from this forum since he also was using a 87 donor harness: http://67-72chevytrucks.com/vboard/showthread.php?t=352321
Ok here are all the pin outs and the color of the wires. My computer is the standard #1227747
A1- grn/wht- this wire is used to power the fuel pump-relay.
A2- no wire
A3- no wire
A4- gry- to egr-relay. This is a ground for the ECM to control the EGR relay.
A5- brn/wht- service soon light. This is a ground to turn on the light.
A6- pink/blk- switched 12v from the ignition relay.
A7- no wire
A8- ornange aldl serial data wire pin-e
A9- wht/blk-aldl pin B When jumpered to ground will set the computer to diagnostic mode.
A10- brn- VSS speed sensor signal to the computer, (This wire I will wire this to on side of a after market VSS sensor and the other wire on the sensor goes to ground).
A11- blk- MAP sensor ground.
A12- blk/wht- System ground. This wire is tied to other grounds in the harness and goes to engine ground.
B1- orn- 12v batt power ( I looked and traced down this wire on my 87 cab harness and this is fuesed I think it was a 15). I will probably use a inline fuse.
B2- tan/wht- Fuel pump signal from the relay. This one ties into several places, the fuel pump, the relay, and the ecm. When the relay is on it sends 12 volts to trun on the fuel pump.
B3- blk/red- Distributor plug
B4- no wire
B5- purple/wht- Distributor plug
B6- no wire
B7- blk- ESC signal This is the knock sensor signal to the computer.
B8- dk grn- AC signal. This tells the ECM that the AC is turned on. I am going to tie this into the ac clutch wire.
B9- no wire
B10-orange/blk- park neutral switch wire. some people say this is optional but I do not think it is because it gives a signal to the computer to give the engine a slight bump in rpm.(if you don't need it why did they put it there?)
B11- no wire
B12- no wire
C1- no wire
C2- brn- wire is not needed
C3-grn/blk- Idle air control
C4-grn/wht- Idle air control
C5-blue/wht- Idle air control
C6-blue/blk- Idle air control C3-C6 all go to the Idle air control valve plug on the TBI it's self.
C7- no wire
C8- no wire
C9- purple/wht-Starter crank signal wire. Goes to the small terminal of the starter.
C10- yel- Temp sender
C11- lt grn- Map sensor
C12- no wire
C13- dk blu- throtle position sensor
C14- gry- signal to map and TPS. ( you will see it tied together in the harness)
C15- on wire
C16- orange- This wire is tied with B1 so it is a 12volt wire
D1- brn/wht- system ground goes to the engine.
D2- blk- tied to the wires for the engine ground.
D3- no wire
D4- wht- distrbutor plug
D5- tan/blk- distrbutor bypass. This is the wire that you disconnect to set your timing.
D6- Tan- O2 sensor ground to engine.
D7- purple- plugs in to the o2 sensor
D8- D13 no wire
D14- grn- Injector plug plugs into the top of injector
D15- no wire
D16- blue- Injector plug plugs into the other injector
Assuming this is correct, and from my other searches the purple wire (D7) I cut and spliced into in the picture to run directly to the o2 sensor should have been correct, since the other threads said to follow it out of the loom on the passenger side coming from the PCM and it was the only purple wire besides the purple/white stripe. however I could not get a voltage reading at all on my analog meter set at 2VDC or 2V AC. I tried using the pigtail i found previously but it has 12V on two of the wires and i think a crappy ground on the 3rd. And from what I have been reading the pcm should be sending .5ish V down the wire not 12V. and the o2 sensor flashes back and forth constantly from .1V - .9V.
I do not have access to a live scanner until monday so I cannot get more detailed readings BUT when the o2 is connected to that wire, after a little bit warming up, when i try to rev to say 4000 it starts to want to die, then picks up again, then hesitates, then revs up. when i disconnect it from that wire it returns to the way it has been for months. I am wondering if i connected to the wrong wire, or if this is how it "learns" fuel trims once in closed loop.
I disconnected it just in case i was connected to the wrong wire.
I think my CEL bulb is burnt out since it did not flash when i jumped the terminals, nor does it turn on anymore when KOEO, but I cannot have the truck down long enough to change the bulb until tomorrow around noon.
I do not have the heater element wired just yet, since the bung is in the manifold before the exhaust attaches, so I was wrong about the location previously.
From what i understand a GM 3 or 4 wire narrowband is simply a 1 wire with a heater or a 1 wire with a heater and separate ground to avoid unwanted readings. And with the heater unplugged it will simply wait till the exhaust heats enough.
The pics also show what was previously in the o2 bung, and the wire i am using to carry the o2 signal, it is a 3wire household extension cord and should have no internal resistance but could be shortened a bit if needed.
I got no readings from the o2 or closed loop when connected to the 12V purple wire on the pigtail, while connected to the live scanner before the shop closed.
I am not getting a o2 code anymore after i reset the pcm.
I mainly need to know if i am on the right wire, and if i am, is the sporadic revving a sign that my used sensor is "getting lazy" and not switching fast enough?
-
oh and my VSS is in fact connected, I drove forward about 40ft pretty quickly and it showed my speed go 1-15mph then down again as i stopped
-
For specifics on the issue at hand read the last few posts by me on this forum to get caught up on what i have and have not tried.
http://www.chevytalk.org/fusionbb/showtopic.php?fid/78/tid/332480/pid/2616292/post/last/#LAST
UPDATE:
I tried leaving the EST wire connected and i disconnecting everything, and by everything I mean EVERYTHING, CTS, TPS, AIC, Spark Control, EGR, the random relays on the firewall, the Alternator, o2 sensor,Knock sensor, anything I could find with a plug except the starter, ign coil, and dist hook ups. even with all that disconnected still backfire blowing fuel out the TBI, bang bang the usual making the neighbors open thier blinds, etc.
I disconnected the EST wire, with all that still unplugged and lo behold it starts, kinda like shoot but ran nonetheless, and could drive it, barely but better than not starting at all.
I thought perhaps my ICM was burnt up or failed, so i grabbed the 048 module i kept in the toolbox just in case, and spent an hour fiddling in the dark and snow to swap it out, the 369 module did not seem hot or burnt or any discolorment, or any smell of burnt electronics, however i swapped it anyway.
This did not solve the problem, albeit the backfire is not nearly as forceful with the 048 and i think that is due to less advance built in.
I tried turning the dizzy back to retard the timing, but it just cranked and cranked and cranked no roar, and if i advanced it past the "original spot" then it backfired faster/harder.
Like i said my timing light is non functional however i will have access to a working one on monday. as well as a scan tool with live data.
My temporary solution was to leave the EST wire unplugged, and advance the timing to the point of starter kickback, then retard it just a hair so it fires up pretty quick.
The current results are I have idle, part throttle and fast "blip" response, I have been unable to test WOT since all the local roads are covered in ice or snow, however earlier I was able to easily rev to 3000-4000 so im 95% sure its not a mechanical issue. It seems like its still trying to retard the timing when im "maintaining" speed, but is just fine when accelerating. I got up to 45mph and held it for about a mile north bound then about a mile and a half southbound. no noticeable hesitation. the engine temp guage was reading about 130-150 since its pretty cold out and my rad is oversized in the first place.
I guess I have a few questions for anyone with some experience
#1 Could a failing ignition coil be causing this? or contributing to it? I can reach high rev's and its not misfiring so thats why I am faily sure the coil is ok, and when it was running I had a firm grip on one wire and it nailed me pretty hard, i have felt weak coils inthe past nail me, and this was not weak.
#2 is it possible that 3 ICM' modules could all be faulty? 2 were pulled from TBI's that drove into the junkard running perfectly, just had body or frame damage from an accident, and my original was replaced because i thought it was causing this issue.
#3 what could possibly be affected by water/mud splashing up from underneath? i do not have all the guards in place but there isnt a lot of water/mud stain anywhere on the engine after i got out of there.
#4 it was idling ok when i pulled into my wife's workplace but it was still stumbling under "cruise" throttle, so i reached in and checked to make sure the dist cap was snug, the truck was still running and the cap was NOT snug somehow i never got the back screw in -.- and when i tugged on it, then there was a visible spark, a bang, followed by the above symptoms, however considering the issue was gradually getting worse i think this was inevitable i just think i gave it a kick in the ass to the "fatal" stage
#5 will it still enter closed loop and use the o2 and knock sensor even with the EST disconnected?
#6 Can i disconnect the 4 pin connector on the ICM and just leave the 2 wire connector setup for the coil? Would it run like this? Where do those 4 wires go to anyway? is it possible that its in there somewhere i shorted or ripped something?
I will attempt a WOT up to redline (6000) or atleast peak TQ at 3,900 to ensure its not a mechanical issue.
When the EST wire is connected and I try to fire it up BEFORE i adjusted the dist, there would be a nice spray of fuel into the air sometimes accompanied by flames when it went bang,
When the EST wire is connected AFTER i adjusted the dist for my current workaround, it starts and runs but BARELY, like it wants to stall but its not letting itself, and if i powerbrake it lightly it backfires ever so gently.
My reasoning is that the pickup coil/stator must be sending the signal otherwise it would not run so smooth through the RPM's with the EST disconnected.
-
Well its gradually getting worse and blew out one of my mufflers :'( :'( so now i have a deep glasspack on instead 8) 8) ;D 8)
Anyway im 99% sure its my stator losing magnetism since I left the EST connector unhooked then advanced my base timing so its driveable but it still backfires and misses some times, and I already replaced the cap,rotor, wires, plugs, and tried 3 different ICM's that were all working the last time they were used. And it barely has enough magnetism to pull a screwdriver or bolt to it.
I grabbed this dizzy from work from the spare/test parts bin. 99% of the time we dont keep anything unless it was working fine and the customer instructed us to change it anyway or if we part out an engine before trashing the car/truck.
I just wanted to ask if this looks correct for a 1987 5.7L TBI block.
I wil be attempting to install it regardless in about an hour just wanted to ask.
-
another pic
-
Well I installed it, its about 15 degrees clockwise from where the "old" one came out but it runs and drives alittle, I will be going to make a grub run here shortly then ill punch it and see how its doing. I found out once i got the old dist out that the "points" were colliding with the other set and i could barely get it to turn by hand, and the one i put in is a slightly different design but i put my OEM GM 369 module in the replacement dizzy to replace the 048 one. I will have to stop and redo the timing tomorrow at the shop with a light, but ill know here in a few if it resolved the issues. I was able to reconnect the o2, knock, and EST wires and it starts, idles, revs and will power brake to 1400RPm fine, but does miss a little as the rpm's come down. setting base timing should resolve that though.
One question I do have is, since the dizzy slid down in at a slightly diffent angle than it came out will that offset my timing mark?
-
Ok so heres the deal, i just got back, i couldnt get it over 3000rpm trying to rev louder than a friend of mine, or over 3000rpm, when i punched it, I tried turning the dizzy both ways to do the "old school" basic timing, ....you know get the maximum vacuum then go down 1inhg usually works for me but in this case i had to crank the dizzy clockwise quite a ways and the wires were pushing on the intake manifold before i got a halfway decent run.
After I went about as far as i could go clockwise i took it for another run, and holy crap, im weighing a good 7000lbs right now if not more with the 454 in the back and all my other crap and it will push me back into my seat :D however I still could not really pass 5000rpm at WOT 1st gear even though i know that i could reach 6000rpm a few weeks ago.
I will check to see my timing mark tomorrow, I will try setting it between 0 BTDC and 4 BTDC since this engine rebuild seems to like advance.
My power curve currently levels off near 4500 when i notice im not accelerating as quick
I just hope this helps someone else one day that is having problems.
Another issue im still having is it wants to cut out when im holding the throttle slightly open for cruising. was almost killing the engine with the inital timing i had, and after the turn clockwise it seems to have gotten better but you can still feel it bog down the surge back to life
-
Ok so got the replacement dizzy installed and re-installed my 369 module and my cap/rotor that were replaced roughly 4000ish miles ago.
Used the timing light at the shop to set timing, it is now at 1 BTDC, my "guesstimate" where it was running decent was about 8BDTC
Fuel pressure has not been tested although i am pretty sure its not my culprit.
I got the same hesitation as before just as bad as before, i tried disconnecting one sensor at a time then driving to see if it would improve, the only noticable difference was with the TPS unplugged it got so much worse i only made it 2 blocks and had to plug it back in. and by disconnecting the o2 it is not stumbling or bogging
I still have a miss though but that has been there a while and i think ive found the culprit for that : When i was trying to turn the dist to time it i got nailed quite a few times and for a while now i have heard a ticking sound when its idling, then a few nights ago i noticed visible arcs from some of the wires to the exhaust or block. these wires were new old stock, meaning brand new sealed but i had them around for over a year before installing them.
I am going to probably replace them all and/or rob the wireset from the RV in the meantime
My results are now that I can accelerate and cruise with the o2 unhooked only
I can watch the miss very noticeably on the timing mark, like it jumps 4-10 degrees retarded when it happens.
I was able to climb up one of the steepest hills (4%) in town during rush hour I went WOT and was able to reach 5000RPM before i really didnt have much more power probably due to lack of timing and i could feel it missing more from about 3300-5000.
Throttle response is excellent currently
I know timing is probably too far back since I used to be able to climb that hill and reach 6000RPM everyday.
-
In case anyone was curious or if it helps the next guy or gal sometime in the future.
I installed the "rumble" glass packs and the miss was EXTREMELY noticable and actually was getting worse.
The weather got super cold the last couple days so i was putting off looking at it, however this is what i discovered and did to fix what i found
I checked the timing, i actually had it about 4-6BTDC and it was running pretty decent, however 2 days ago i adjusted the dist to 0 BTDC (by ear and using a vacuum gauge) no im not lying, i checked it with a timing light today and it was dead on 0 but at 0 BTDC i get that surge very noticeable at roughly 2000RPM again, so im thinking whatever they did during the rebuild that it likes a little more advance so i re-timed it using the method i use for my 77 450hp 302, max out the vacuum reading, then back it off just about an inhg, which put me about 3ish BTDC.
I got home and i knew the #1 had a miss, so i grabbed a new wire off the 400 and pulled off the #1 wire on the 350 and it literally was melted in half, no idea how since the split was up near the intake. i replaced it and now that miss is gone.
I notice a pitter patter in the exhaust but ONLY drivers side and i cant get past 5000ish RPM anymore. oil level is good and good oil in it. but I did the paper/dollar trick and it pulls it in and out with every revolution of the engine, and its steady. the otherside does NOT do this, and sounds perfectly normal.
From what i have read this is usually a sticking or bent exhaust valve or excessive overlap, im pretty sure the cam is not that aggresive. My next step will be to pull the valve cover off when it is running and make sure everything is tight and lifting evenly.
If that all checks out then my next check would be a compression test since some say the "flutter" could also be a headgasket
I think i may already need new plugs because of the pickup failing and the running lean for over 4000 miles, I will check them on the next warmish day.
Is there anything obvious im missing?
I reconnected the o2 to see if the broken wire was actually throwing off the o2 because of the misfire. My wife gets off work at 1130 and I will find out if it wants to run right.
-
Well tightening the rocker arms actually helped some, it can now get to 5800rpm again but it still struggling and spitting when i get past 5000, going to check the otherside this weekend after it rains, the dollar trick doesn't suck in as much anymore if at all but still a slight miss, which im not sure is wires, cap, rotor, or plugs. i think ill do a full tuneup before missouri. I have not been able to use the o2 yet since the surge still happens.