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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: DanMcG on August 21, 2020, 04:32:59 pm
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My 78 has a 86 305 with hei ignition. It has fuel coming out the exhaust, wet plugs and a yellow spark. The plugs and wires have less then an hour on them. I tossed them in when I bought it a couple years ago to get it running.
It will fire up and idle right off the bat, idle is rough.
So today I tossed on a new coil only to find no difference in the spark color. Could the cheap wires I have on it be a issue, I got no problem spending on good wires if it means it will stop the fuel in the exhaust system. but I really dont like throwing money at it till it's fixed
Any thoughts?
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Fuel coming out of your exhaust sounds like your carb need some attention. Also, the idle could be a timing issue. Cheap wires on a non performance 305 shouldn’t make that much difference.
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Fuel coming out of your exhaust sounds like your carb need some attention. Also, the idle could be a timing issue. Cheap wires on a non performance 305 shouldn’t make that much difference.
I agree on the carb being an issue and have a carb kit on it's way. But the yellow spark has me wondering if it should be white/blue or not? For what it's worth the arc will jump 3/8"
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Sounds like you have a fuel/carb problem before anything else.
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My 78 has a 86 305 with hei ignition. It has fuel coming out the exhaust, wet plugs and a yellow spark.
I agree on the carb being an issue and have a carb kit on it's way. But the yellow spark has me wondering if it should be white/blue or not? For what it's worth the arc will jump 3/8"
HEI should arc a minimum gap of 5/8" and produce a blue-white spark. Make sure the distributor is receiving full I+ while running then look to the ICM since the coil is new. Is the coil ground strap in the cap intact? Inspect the terminal block between the cap and ICM to verify sound connections.
What do you mean by, "fuel coming out the exhaust?" Is the tailpipe black with soot, is the exhaust puffing black smoke, or are you referring to condensate dripping from the tailpipe?
Check thoroughly for vacuum leaks using some carburetor aerosol cleaner and validate the ignition timing.
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By fuel coming out of the exhaust, I mean liquid gas it spraying out of the worn out donut gasket is at the end of the exhaust manifold, you can see it on the frame rail
(http://pic20.picturetrail.com/VOL1312/13773522/24860247/414462812.jpg)
My plan it to change out the ICM or just buy one of the cheap complete distributors they sell everywhere. and rebuild the carb. and see what happens.
All I need to do is move it around the yard a few times a year, but I don't need a flame thrower under the hood while I'm doing it.
Thanks for the information bd, I'll be back later in the week with some updates I hope, Dan
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I agree with Bd...make sure your carb is tuned properly, and then pull you manifold and replace the gasket. What yo7 have there is a safety issue as well, as you don’t want raw gas dumping on hot surfaces...
I would venture to guess, thought, to answer you orig. post, that cheap plug wires are not your answer.
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I wouldn't buy one of those skip white or other cheap distributors. The proform one isn't bad. But that can probably wait.
Some parts stores have the ability to test the module. Is yours a five pin module for the ESC? If you don't have the ESC hooked up, that can be a problem. May have to search if you can swap in a 4 pin, I don't quite remember.
What coil did you buy? A lot of the internal ones are junk, especially the "high output" ones. The epoxy holds heat in and they fail weirdly and without a run tester, it's hard to find that they failed. I would recommend a stock coil or close to it. That's probably your cheapest option to get that squared away.
Borg Warner makes some decent wires at a cheap price, but the ones you have are probably okay for now.
I'd get the carb rebuilt and then check the module out.
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Just a quick follow up, I changed out the ICM and rebuilt the carb and it's running incredibly well. To bad I only need it to run so I can move it around the yard....
Thank for the suggestions and advise, I sure do appreciate it!