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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 454 Camper Special on May 23, 2015, 06:58:31 am
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78 Chevy Camper Special 4x4...
Having issues with finding the rite carb... Had a 600 Edelbrock on it...but learned that the 383 should have a 750 cfm carb... So I tried a Holley 770 Street Avenger... Ran sweet...nice and crisp..! Stepped away for a minute and she stalled...! Won't start back up...! Has the Edelbrock Performer RPM power package... MSD Pro Billet HEI... New plugs n wires... I'm open to suggestions... ???
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What I really want to do is build that 77 Big Block 454... And make a freakn stump pullin monster..!!!
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i wont need a 750 unless youre turning 7500 rpms. generally speaking a 600 is good enough for a 454 turning 5500. if youre looking at a carb set up for racing then yeah a 650 would be good for 5500 rpms. what are your max rpms you plan on turning?
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Determine whether it is getting fuel and spark. Using a flashlight, do you observe a strong shot of fuel into the carburetor throats as you open the throttle? Remove a plug wire from one of the spark plugs and connect it to a spark plug that is laying on the engine so the metal base is solidly grounded - do you observe a strong blue spark as an assistant cranks the engine?
Remove a few of the spark plugs. Are they wet?
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Before you start buying new parts, definitely consider the answers to Irish's questions. You can run as many CFM as you like...all depending on your application. Remember that your Performer Rpm (dual plane, I assume) has an rpm range....if I remember correctly, 0-4 or 5000 rpm. (Imo ditching the Brock was a good idea)
Then troubleshoot using Bd's instructions.
78 Chevy Camper Special 4x4...
Stepped away for a minute and she stalled...! Won't start back up...!
Meaning, it won't turn over? Or it turns over but stalls when you let off the pedal?
You have all of the right parts. The guys I'm building hot rod engines with hate the HEI distributors. Once you change displacement and cam lifts, vacuum changes, and complicates vacuum advances. We use the 85551 and an ignition box....then tune the distributor using the advance kit and rejetting the carb as needed.
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we all have made this mistake before. but you sure you have gas in the tank?
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Right now the ol'girl has a 383 stroker...pulled the 454 to build... The 383 that's in it now turns 5,500-6,000 rpm tops...geared low...TH-400
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Yeah I thought it ran out of gas too...as my gauge isn't working...so I went and put another 10 gallons in it.. so it has gas
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Just bought new NGK G-Power platinum plugs...gapped em .045... Gonna see what happens
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No I had it idling...went inside for a minute...came back out and it had stalled... Thought it was out of gas...but wasn't... Put another 10 gallons in for shits n giggles... Whirled her over...nothin... Just wouldn't start back up... I'm guessing the 770 is to much carb...
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I have a 600 & 750 Edelbrock...and a 770 Holley Street Avenger...vaccuum secondary's at my disposal
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did you pour a little gas into the carb to see if it will fire up?
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Hey... I appreciate you all giving me advice... Thank you very much... It's nice chattin with knowledgeable gearheads that have a passion for raw horsepower as myself...! :)
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Going out to try an get her fired up... I'll give yas a shout inna bit with my results k...
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Hey... I appreciate you all giving me advice... Thank you very much... It's nice chattin with knowledgeable gearheads that have a passion for raw horsepower as myself...! :)
(http://www.naioa.com/v2/modules/Forums/images/smiles/lol_hitting.gif) shhh this guy thinks we're knowledgeable
(http://www.animateit.net/data/media/august2009/typing_guy.gif)
and gear heads
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No I had it idling...went inside for a minute...came back out and it had stalled... Thought it was out of gas...but wasn't... Put another 10 gallons in for shits n giggles... Whirled her over...nothin... Just wouldn't start back up... I'm guessing the 770 is to much carb...
Definitely not too much. I just checked....the Performer RPM intake matches carbs rated from 600-800cfm....so even your smaller Edel was okay.
Right now the ol'girl has a 383 stroker...pulled the 454 to build... The 383 that's in it now turns 5,500-6,000 rpm tops...geared low...TH-400
And the Performer RPM operates between 1500-6000RPM. So you're good there too.
Did you check to see if you have spark before changing the plugs? Have you checked the fuel lines and filters for obstructions? Is the fuel pump operating? Is the throttle opening? Is the manual choke stuck? Have you adjusted the idle screw in the Holley?....try opening it.
I'm with Irish on this one....sounds like you're not getting fuel as opposed to having too much carb. If you have spark, then it's likely a lack of fuel. If you have spark and fuel, then your problem is compression (and we pray that's not the case).
(http://www.naioa.com/v2/modules/Forums/images/smiles/lol_hitting.gif) shhh this guy thinks we're knowledgeable
(http://www.animateit.net/data/media/august2009/typing_guy.gif)
and gear heads
LMAO ::)
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the formula for finding the cfm of a carb is (max RPM x CID x volumetric efficiency / 3456=CFM)
a stock motor is prob around 70%VE a tuned is about 85%VE a professional is 95%+
so with that said
6500rpms X 383 X 90%VE (and thats prob a little much)/3456=648.
i dont want to get into whats his best carb when a carb isnt his problem right now after we fix the non running issue we can dip into "best" carb
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the formula for finding the cfm of a carb is (max RPM x CID x volumetric efficiency / 3456=CFM)
a stock motor is prob around 70%VE a tuned is about 85%VE a professional is 95%+
so with that said
6500rpms X 383 X 90%VE (and thats prob a little much)/3456=648.
i dont want to get into whats his best carb when a carb isnt his problem right now after we fix the non running issue we can dip into "best" carb
agreed, but good to know. Thank you.
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Yeah....well... Brought her up on tdc #1.. Gonna check the coil... It just ain't firing..
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Put the 600 back on...cause that's the last time she ran... Plugs are wet.. Turned the regulator all the way out... Thinking it might be gettin too much fuel pressure.. Bought ready to check the coil...can't see it being that though...roughly a year old MSD Pro Billett HEI... Got the ignition wire right side...tach going to the tach wire they provided... Got the 6-AL box on firewall...just waiting to be wired...thinkin on lockin it out for mechanical advance instead on vaccuum on that 6-AL...
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If there isn't any spark, check for switched B+ to the ignition system. Since the symptoms occurred shortly after you installed the Holley, look for any wiring you may have nudged or knocked loose or grounded inadvertently.
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Sorry.. haven't been checkin my messages.. Making haist with what daylight is available...
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i'm just going to assume you havent checked the float level ? ive installed a few carbs over the years where somebody at the factory either didnt set right or set it at all
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Firing issue's... No fire... Getting gas... Thought maybe it was over carbed...as my plugs are soaked... New NGK Platinum G-Force... 8mm Accel wires... Ran 2 weekends ago then just quit... I've narrowed it down to no fire... Why would it run...then quit and not fire again... Tested the coil and ignition wires with a multi meter yesterday... 11.5 V.. ??
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And also I brought it up on the compression stroke dtc #1... rotor button pointing to #1... and on the cap #1 plug wire is right lined with rotor button... checked and recheck firing order... It's rite on... You suppose the module in the HEI would fail it would cause it to quit.. ?? Maybe I should be checking that too..??
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i'm just going to assume you havent checked the float level ? ive installed a few carbs over the years where somebody at the factory either didnt set right or set it at all
Yeah I checked em... All good
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Narrowed it down to no fire... It ran 2 weekends ago then just quit... Haven't been able to fire it back up since...
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I'll check switched B+ to the ignition... It's gotta be electrical...
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Well I checked B+ wire.. Heavy pink wire from firewall wire block... Brown tach wire to tach side... Firing order on MSD Pro Billett HEI starting from ignition and tach block.: 21843657... On compression stroke rotor button line up with #1 wire... I don't get it..!!
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I can't see it being the distrutor... farely new..! Unless I'm advanced to far on initial...?? That shouldn't matter though...
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454 Camper Special, stop creating new threads regarding this problem! Keep all of your posts regarding this issue contained to this thread!!
Now, is the coil married to the cap or divorced? Do you have a test light?
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10-4! Married..! Sorry I'm new to site...
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Have a multi meter...no test light
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Multi-meter will work, but a test light would work best and there is less issue with interpretation. Digital meters may not have the necessary response rate - the voltage may fluctuate too rapidly for the meter to display anything useful. In this scenario, an analog meter will outperform a DVM. You should pick up a 12v test light for future use.
Connect your meter across the coil primary connections and crank the engine. Does the display/needle fluctuate?
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I bet it is the Ignition Module. It is located inside the distributor under the rotor cap. It is bolted down to the top of the metal plate with two screws. They are pretty cheap as far as cost too. They can develop a crack and you won't know it until it kills the engine. I always start with this first if I am not getting spark. They are cheaply made now of days so you want to carry an extra one. All you need is a screwdriver to fix this.
I had my truck quit on me going down the road one time. It was a very weird feeling to go from 1500 rpm to nothing. It would not start either. I had to have it towed home. I learned after that to always have a spare in the glovebox. They are cheap insurance. It will happen to you once and you will know instantly what it is when or if it occurs again.
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And also I brought it up on the compression stroke dtc #1... rotor button pointing to #1... and on the cap #1 plug wire is right lined with rotor button... checked and recheck firing order... It's rite on... You suppose the module in the HEI would fail it would cause it to quit.. ?? Maybe I should be checking that too..??
I went back and reread this thread. I honestly think you answered your own question. I will be very surprised if it is anything else.
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Yeah... I hear ya.. It's the dang module..! What would cause the digital module to fail..?? I noticed I have voltage coming off ignition wire and also tach wire..?? This normal..?? Wiring is a nightmare in that truck..!! Was just sitting and idling when it quit.. $105.00 for a new MSD module... Or I could bypass it and wire up the digital MSD 6-AL box..
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I've been just steering away from using the box due to the wiring disaster of the truck.. (78 K20)
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What the truck really needs is a Painless Wiring kit..!
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Just want to say thank you for the help fella's...and at the same time...apologize for the inconsistencies...venturing off the thread...like I said before...this is the first time on a forum... But like I've heard is true... Pretty dang knowledgeable people... Much appreciated..!! :)
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I looked up at the top of the screen at the followers... 456 followers..!! It's pretty coincidental...! Cause that is the gear ratio I wanna run.. 456's front n back...that is after I can save up enough scratch for the Dana 60 front to work with the 14 bolt corporate rear... Want a NV 4500 tranny... but for now the Turbo 400 mated with the NP 205 will do... Only trouble is..She just beggs for another gear!!! :) Lol
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Yeah... I hear ya.. It's the dang module..! What would cause the digital module to fail..?? I noticed I have voltage coming off ignition wire and also tach wire..?? This normal..?? Wiring is a nightmare in that truck..!! Was just sitting and idling when it quit.. $105.00 for a new MSD module... Or I could bypass it and wire up the digital MSD 6-AL box..
How did you actually determine the module is the culprit?
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Put the AC Delco Remy back in to cross reference it
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I have a goldmine of Ol'Skool GM parts...motors etc...etc.. to fall back on...
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Well.. for some reason the brown tachometer wire is live.. 11.5 V when the key is turned on... ??? I was under the understanding that the tach wire shouldn't be live until it's plugged into coil... Mine is live before connected to the coil... ??? I think that ruinned the module... The day it quit I had it connected to the designated tach wire that the MSD Pro Billett HEI distributor has on their distributors...??? Not certain...but I believe that's what happened to the module... That distributor sat on the workbench all winter...It might have 2000 miles on it... Discouraging....!!! :/