73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: kopeck on October 27, 2016, 09:37:16 am
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I wish things would just break so that I knew what I had to fix...
Anyway, driving along a 55mph the engine just died on me, I didn't notice and sputter, bucking or anything like that, it was just gone. I pull over, turn the key and it starts an runs for a second and then that's it. No amount of cranking will get it going.
The gauge said it had a half a tank but I threw 3 gallons in to see if it ran out of fuel. The gauge did go up a tad, but still no joy. The accelerator pump seems to be working when I pushed it manually, I also poured a bit a gas in from the top...nothing.
A friend stopped and he had a set of pliers and a a long Phillips bit, we pulled a plug wire, stuck the bit in the boot to see if spark would jump to ground, nothing. So we're missing fire, or it seems that way anyway.
I get it towed home.
This morning I go out and move my work stuff over from the truck to the car, for the fun it I turn the key and it fires right up and seems to run fine. I get it into the garage so I can stick the batter charger on it and that's where it stands.
Any ideas? If it stayed dead I would have started checking things in the distributor but now it's alive again so who knows what's going on. I'm thinking ignition control module but who knows at this point.
K
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Remove and inspect the distributor cap, especially in the area of the carbon button. Look for evidence of pitting and ashy discoloration. Check the connection of the B+ primary wire to its terminal on the side of the cap and inspect the three-wire primary harness inside the cap. If all appear okay, replace the pickup coil and module.
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Check both battery cables for condition and tightness.
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I agree with the other guys. Check your grounds and battery cables first. It's probably your ignition module. After that check the coil. Look at cap and rotor while it's off.
I carried a module and tools in the glove compartment when it was my daily driver. They don't go out often, but there is usually no notice, they just quit.
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Don't overlook the coil itself.
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Remove and inspect the distributor cap, especially in the area of the carbon button. Look for evidence of pitting and ashy discoloration. Check the connection of the B+ primary wire to its terminal on the side of the cap and inspect the three-wire primary harness inside the cap. If all appear okay, replace the pickup coil and module.
to go with what he said
http://forum.73-87chevytrucks.com/smforum/index.php?topic=29995.0
If parts test bad check out eBay for being hei distributors for sbc. You can find them for around $50 and it will be all new parts
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Thanks guys,
Kind what I had in mind, just a visual inspection and then go from there. I have a new cap sitting on the shelf anyway, probably grab a new rotator on the way home just in case. If everything looks OK then I'll get the module.
Oh the the battery terminals were tight. I went though the grounds a year ago or so, they should be fine.
K
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Hi Guys,
Using Irish_Alley's coil test it looks like the primary side of the coil is shot. You put the meter on it and the numbers jump all over the place but then settle to 0. The Secondary tests fine...not that it matters.
Before I tested the coil (somehow I missed the link) I installed a new cap and rotor I had on the shelf. The truck would start, run for like 15-30 seconds then just shut off. You could restart it right off but it would do the same thing. I stuck my timing like on it and it just like the key was switched off.
Think I should replace the ignition module too or just go with the coil for now?
Thanks,
K
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If you think it's the coil, replace it and see what happens. No need to replace parts that aren't bad. You can easily change the ICM if the problem persists - it's the pickup coil that requires removal of the distributor.
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I just went thru this on my 79 c15 with 350 engine as well. The dizzy had moisture in the cap and rotor, so I replaced them. A week later same issues, so I just went ahead and swapped a new Spectre dizzy from Oreillys along with tune up, wires and plugs. No issues since I did this. Good luck and keep us posted
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She runs!
Turns out it was the ignition module. I did install a new coil as well since the old one wasn't testing right on one side.
I took the opportunity to throw on a new set of wires and the cap and rotor I had sitting on the shelf. The wires I put on 16 years ago were awful, just way to long, some had over a foot of slack! I had a few coiled up and zip tied...not sure if it was just a poorly made set or if I was given one for another application, none the less it's much better now!
So my old, pretty worn, leaky 350 has a nice fresh ignition system. ;)
Thanks for the pointers,
K
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Glad to hear the good news bud. I just bought a 90 camaro v8 and having to drop the dang rear tank that is full of rust, and ruined a new fuel pump and sender.
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It's never easy...
The last two days I've driven the truck quite a bit. 3 times it's it had momentary misses, it sound like it's coughing back through the carb (I heard a pop from the dash area). Each time it's been after the truck was fully warmed up, let sit for a short while (30 minutes or so) and then driven normally. It doesn't last, but for a few seconds and once it's done, it's done it runs fine. I drove it for 20 - 30 miles at all sorts of speeds and loads and it runs fine. It seem to happen fairly soon after starting and under initial acceleration (ie pulling out onto a road and getting up to speed).
Kind of sounds like a lean issue but A) I haven't changed anything and B) why would it fix it's self and do it so quickly.
Maybe a faulty new ignition module? It doesn't seem like the cap, rotor, coil or wires would do stuff like that...
K
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So my truck is still having periods of missing badly.
It seems to be as it's warming up. At high idle/choke set it runs fine. When I first take off but don't push it/put the engine under load it's OK too. As soon as I load the engine it breaks up, sometime coughing back through the carb.
After things get warmed up it seems to run just fine. Today was the coldest (low 30s) that I've run it since this problem poped up so it took a while to "fix" it's self. It never did this until the ignition module died on me. I guess it could be a lean issue but I didn't touch the carb, it seems like it has to be in the ignition.
Any ideas where to start? It's intermittent, which is frustrating as all get out.
K
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make sure you don't have weak springs or sticky weights in dist
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make sure you don't have weak springs or sticky weights in dist
Now that you say that...I fooled around with the weights because they were a mess. I wiped them off and stuck them back in but they didn't seem any better. The bushing were kind of sloppy but I stuck it all back figuring I would work on them later. I wonder if they're sticking now.
I'm sort of thinking I should have just bought a new distributor. I've already got almost as much into my old one as a new Summit aftermarket job...
K
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been there best out .....is replacememt my oil gear had sloop to......that will cause hesitation in carb also
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Yeah, I'm thinking I might just get a new one at this point, it's not worth the head aches. Seems like it has to be ignition but then again anything is possible with an old truck.
The truck was all over the place today, sometimes real crap and others as good as can be expected from a well loved 350.
Most any time you came to a hill and eased into the throttle a bit to maintain speed I could feel it miss a little, if I gave it a bit more throttle to try and gain some speed it would get worse to the point where it almost feel like there would be a split second stall followed by it coughing.
Then I took off down a main road and it ran with out a miss @ 55 - 60 MPH. Let it cool off and it was back to missing on my way home.
K
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I'm dredging up a topic from last year but it's the same problem so this seem easiest.
The truck still had it's weird miss/cough issues when I put it away late last fall. Since this all started with ignition and the distributor is the only thing I've touched (other then adding new plug wires) I'm going to assume the problem is still in the distributor.
In stead of piece-mealing my way through my old unit I was thinking I would just get one of these:
https://www.summitracing.com/parts/sum-850001r/overview/year/1979/make/chevrolet/model/c10 (https://www.summitracing.com/parts/sum-850001r/overview/year/1979/make/chevrolet/model/c10)
JEGs has a similar unit, I'm sure they're pretty much the same as the $50 dollar eBay units. At least the Summit unit comes with a 1 year warranty and it isn't likely that Summit's going anywhere. That and the reviews are good.
Seem like a logical next step? I usually like fixing the underlying components but a new pickup and bushings are going to cost me nearly as much as the whole unit...
K
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Before you replace the distributor, use your ohmmeter to measure the resistance of every spark plug wire; original type carbon core wires should measure roughly 1,500 ohms per foot of wire length - any wire measuring over 5,000 ohms should be replaced. Aftermarket spiral core wires can measure as low as 30 ohms per foot. Inspect for black soot or any greenish discoloration inside the spark plug wire boots at both ends - traces of soot or discoloration calls for replacement. Start the engine in a dark environment and have an assistant load the motor while you watch for arcing from the spark plug wires, especially between the spark plug boots and surrounding heat shields or exhaust manifold. Remove the spark plugs using a rubber insert spark plug socket and inspect for a cracked ceramic insulator and general spark plug condition. Afterwards, if you think the distributor is still the cause, the linked Summit distributor should be a suitable replacement.
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That's all pretty easy stuff to check, I'll give it a look before I throw more money at the problem.
It would surprise me if I needs new plugs...while it hasn't been a ton of miles it's been 15 years.
K
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Or maybe this is the reason why I was having issues...
That's brand new cap and rotor. What would cause that? The only thing I can think of is the rubber seal/dust cover that the button sits in was really stiff unlike the OE one that wasn't at all. Maybe it caused to much friction?
K
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That's a common result of protracted arcing between the carbon button and rotor contact due to button wear. I've seen 1 1/4" diameter windows burned through the cap center and still produce a "perfect" scope pattern and run fine. Couldn't believe it. Replace the coil (AC Delco or MSD) along with the cap and rotor so you don't experience a ghost misfire.
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Yeah, I was just reading that after doing some googleing.
The coil is brand new (CarQuest in house brand), the Cap, Rotor and button/busing/brush were all new (Accel brand I think, or maybe Summit).
I wondering if the tab wasn't bent up enough on the rotor? It looks like there was contact being made, or was at some point.
They also talk about plug gap causing this. As far as I know the plugs were gapped to spec (.045). The old cap wasn't like this at all, it was age worn but not burned in any way so it survived these plugs. I did change the wires, not sure if that could be a factor.
K
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A couple of more picks and observations...
First off, the cap & rotor was made in Canada...darn imports. :)
Second, there was some arcing around the terminals on the cap, kind of looks like the batt terminal. Not sure if that add any clues to he mystery?
Third a picture of a messy rotor for fun.
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Those are either Accel or Echlin cap and rotor. Post pics of the coil side of the cap and the brush contact pad of the coil. Are you saying the cap burned away after you installed new cap, rotor and coil? How many miles does that represent? Did you reinstall the ground strap between the coil frame and terminal bulkhead on the side of the cap?
HEI produces upwards of 35kV across an open circuit. That much voltage will break down dielectric components and create its own current path eventually. Once a new current path is established, discharge becomes progressively easier, because of the resultant carbon path.
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That's exactly what I'm saying. That cap, rotor, button and coil combo has around 500 miles on it.
When the truck died originally I had the cap/rotor/button & a set of wires on the shelf. The cap and rotor very well could have be original (all Delco parts). I had been meaning to freshen everything up (the wires in the truck were crap) for a while but it just kept on running so the parts sat on the shelf. The first thing I tired when the truck died was a coil so I just swapped out the other new parts at that point. The old coil did test right on the edge of one of the specs though. The ignition module was the root of the problem though.
For the record the button was installed correctly (cap - button - rubber seal - coil) and the ground strap was installed on the coil.
I'm kind of worried that if I throw a new cap/rotor/button at it I might have the same problem all over again.
In my mind something's creating resistance. Maybe there was an air gap between the tab and the button but it doesn't look like it. I'm going to test plug wires tonight when I get home from work. The old cap wasn't burned so something changed. I don't see anything else in the cap or on the rotor that would indicate they were faulty.
Here's the top of the cap:
K
Edited to add photos of the coil. Is it normal for the windings part of the coil to be loose on the metal frame?
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Based on the images, the issue was with the carbon button. All of the damage is limited to the small area surrounding the button and rotor contact. There may have been a problem with composition or manufacture of the button that caused premature wear or failure of the base material. Once a gap developed between the rotor contact and the button, arcing rapidly eroded the remaining button away. Gradually, arcing migrated to the larger area of the coil pad around the edges of the button flange, taking the lowest energy path to the rotor. Again, use either an original AC Delco cap and rotor or aftermarket MSD. Consider smearing a small amount of dielectric grease on the tip of the new button, on the rotor tip and on each of the eight terminals inside the cap. The coating will turn to a conductive ash and decrease erosion of the terminals.
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Sounds good.
The local auto parts place has a MSD cap and rotor kit in stock. I'll get it and see how she goes. I wish the caps were not red. ;-)
Thanks!
K
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If you prefer black, purchase the AC Delco. :P
What you never want to do is mix cap & rotor brands. Although this rule pertains more to conventional ignition systems than high energy ignition, always match the cap and rotor using the same brand. Otherwise, the air gap between the rotor tip and wire terminal maybe excessive, resulting in a ghost (intermittent and random) misfire.
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Well...
They didn't have a MSD but they did have a Accel kit. I know it's at least a known brand.
It seems better built then the other one, a tad heavier. It's of course a brown/gold color. Better then the tan one I had right? *cough*
I hope to slap it back together tomorrow.
K
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Put it all together and it started right up and idled fine. Gave it a little throttle and it ran rough. I took it out on the road and every time you gave it even a little gas it would break up pretty bad.
Nursed it home, pulled the cap and got out my multi-meter. From what I see I should .5 and .6 between BAT and TACH. I'm getting .6 OHMS.
The next test is between BAT and the carbon button, I should be seeing between 6k and 30k, I'm getting an infinite reading.
I also see a test between ground and the button, I guess I should see between 5k and 11k I'm getting 7k.
Just double checking my self here but I have a bad coil don't I?
K
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After a bit more reading it looks like an infinite reading between the button and BAT is normal. Maybe the other reading was for older OE coils?
I've seen multiple people post see the same thing. They do the test, find the reading between BAT and the button to be infinite, order a new coil only to find the new one test the same way.
The strange thing is it ran better with that burned up cap and button then it does now. The only thing I changed was the cap. The tab on the rotor is making contact with the button.
K
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- Verify the spark plug wire firing order, 1-8-4-3-6-5-7-2.
- Remove the distributor cap and flip it upside-down. Post images showing the bare primary terminals on the side of the cap and the pickup coil wire pair and connector plugged into the ICM.
When you replaced the ICM, did you clean and then liberally apply dielectric grease to the underside of the new module and its mounting surface?
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I hope to get out with a clear head and look at everything really close today. Working after 9:00pm isn't ideal for me....
I did double check the firing order, triple checked even. It idled just fine but as the RPMs increased it started running rough. It's almost like the advance wasn't working.
I did clean everything up and I did apply the thermal paste to the underside of the module.
I have new plugs. I a moment of weakness I picked up a rebuilt (NAPA) distributor. I had instant buyers remorse though. It was kind of expensive and when I got home and looked it over it really looked like they just put the parts though the washer, threw some new weights in and called it a day. All the electrical stuff looked "vintage".
I'm going to work with what I have and if I really need a new unit I'm going to go with something that's really new.
I'm also planning on testing the wires. Summit says they should be 270 ohms per foot.
K
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Checked the wires, they're OK, the longest one read 627 ohms. Installed new plugs. Even installed the old coil, same deal. Starts fine, idles fine. You can run the RPMs with no load and it seems OK. Drive it and normal acceleration causes it to break up bad. You can be really easy on it and coax it up to 35 or so but after that i just wants to run like crap.
Are these what you wanted for pictures?
K
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Replace the distributor.
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It's that time eh? Thanks for being patient with me, I really appreciate the help.
One thing I did today (didn't have a ton of time being it's Easter) is I stuck the timing light on it. It had an initial timing of between 5 and 6 degrees. I bumped it up to the 8 that's on the sticker, I had 20 degrees total timing after that.
I kind of doubt 2 degrees is going to do much. I know I've read a lot of folks like to have 12+ degrees initial and 30+ total. To get to that total I would have to be running like 18 initial, that seems kind of high. Maybe my distributor just doesn't have that much advance in it...
K
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Time for an update! Got the new distributor in and it runs! Not really sure what was wrong but the engine runs pretty well. It's still a tired, leaky 350 but at least it goes. I am going to have to go and play with the carb a bit as it's picked idle RPM. Just didn't have time plus I ran into something new...
I noticed is it almost sounded like there was some spark knock going on, at least that's what I thought it was. It seemed to come on under slight to medium load. I ran it like that all day thinking it might just be old gas and wanted to get the tank down so I could get some fresh stuff. It got louder and louder and it's become clear it's not spark knock at all. It sounds like something hitting a heat shield and by the time I got home there was an occasional squeal as well. It was intermittent though. I spent an hour crawling around under truck wiggling stuff and couldn't find anything. The only thing I did notice is that with one rear wheel jacked off the ground and the truck in neutral there was a low whine that came from the transmission when I rotated the drive shaft. Not sure if that's normal or not.
I tired to pull the dust cover to take a peek at the flex plate the the exhaust wont let me pull it out.
With the windows closed it sound like it's coming from below the cab, with the windows open and my head hanging out it sounds more like it's coming from under the bed.
If it's not one things it's another...
K
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Pick up a 3' long, 1.25" ID Vulco coolant hose. Use that as a flexible listening tube to isolate the source of the noise. The hose will dampen ambient noises coming in from the sides while it channels sound from the open end of the tube. It functions somewhat like a stethoscope, but is better suited to high-noise environments.
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Thanks for the tip, I've done that with big screw driver before but it only seems to make noise going about 35 - 45MPH. Not sure I want to be under the truck then. ;)
I think I might have the local shop give it a look. He's a recently "retired" dealership mechanic who worked on wide bodies when they were new. I'm all about DIY but I think this might be easier to chase with it on the lift.
Truth be told I think time is just catching up with the old girl The engine needs a rebuild, the transmission probably does too.
K
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I'm 99% sure the front U-Joint is toast. Still seems tight but the noise is most defiantly coming from that area.
I hate it when the Distributor takes out a U-Joint...
K
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Just to add a little closure, the front U-Joint was on it's way out. More dry then anything, replaced the rear while I was at it.
No more funning noises, the truck seems to be running pretty well for what it is. I think it's time to start making a plan for "reconditioning" though...That's for another thread. Right now I'll drive. :)
Thanks for the help,
K
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Glad to hear you got it all sorted out. Well done!
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Just an FYI, don't use "performance" components in a stock application like Accel. They typically use low resistance carbon buttons and you will end up with a burned through cap. Always use high quality ignition components and don't mismatch parts/brands.