Carbed LS1 diesels when shut off
05-19-2011, 02:32 AM
#21
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I know this is a dumb question, but both *speedtigger* and myself had a lapse on this just recently. The Performer RPM has a 10/32 threaded hole on one of the front runners to bolt MSD box on. You would think this would be a blind threaded hole, but it goes through into the runner. If you don't use it to bolt the box on, it needs a 10/32 screw in it. Just a thought, Ron
05-19-2011, 01:16 PM
#22
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Ive seen this first hand. One wire alternator also. It was backfeeding 12v to the ign side of the MSD
05-19-2011, 08:03 PM
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05-20-2011, 03:12 PM
#29
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i had this same proble in an old s10 i built with a v8 in it years ago. i found that when i shut key off it would still half *** run. i actually ran a toggle switch under dash to act as a key and ran a push button start. took care of problem. i still used key for all other things though. hope i was some help and good luck fixing the problem. i hate small annoying things like this
05-23-2011, 11:59 AM
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If the problem were related to a one wire alternator the car would simply not shut off until the one wire feed to the alt were disconnected but im guessing it would depend on how the 12v ign feed to the MSD was wired.
Hope this helps diag.....
05-23-2011, 07:25 PM
#31
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Whe i put my Caddy together the electric fans would actually produce voltage until they stopped spinning. The engine would continue to run crappy for a few moments even though the ign was turned off, then it would shut off once the fans slowed enough. I moved the power source for the fans to a different battery voltage circuit and problem solved. You can easily check this condition using a test light the ign source circuit to the msd box(red wire) and should instantly go out not dim out slowly.
If the problem were related to a one wire alternator the car would simply not shut off until the one wire feed to the alt were disconnected but im guessing it would depend on how the 12v ign feed to the MSD was wired.
Hope this helps diag.....
If the problem were related to a one wire alternator the car would simply not shut off until the one wire feed to the alt were disconnected but im guessing it would depend on how the 12v ign feed to the MSD was wired.
Hope this helps diag.....
05-28-2011, 08:23 PM
#32
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Ok anybody want to buy an ls1?? Ive tried it all and it still diesels when I shut it off. I got it to stop dieseling but then it wont idle in gear... Is it cause I have 91 fuel?? Should I have an higher octane??
05-28-2011, 08:30 PM
#33
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Whe i put my Caddy together the electric fans would actually produce voltage until they stopped spinning. The engine would continue to run crappy for a few moments even though the ign was turned off, then it would shut off once the fans slowed enough. I moved the power source for the fans to a different battery voltage circuit and problem solved. You can easily check this condition using a test light the ign source circuit to the msd box(red wire) and should instantly go out not dim out slowly.
If the problem were related to a one wire alternator the car would simply not shut off until the one wire feed to the alt were disconnected but im guessing it would depend on how the 12v ign feed to the MSD was wired.
Hope this helps diag.....
If the problem were related to a one wire alternator the car would simply not shut off until the one wire feed to the alt were disconnected but im guessing it would depend on how the 12v ign feed to the MSD was wired.
Hope this helps diag.....
05-29-2011, 08:55 AM
#38
^^ what he said
You might have gunked it up trying to make it run with the vac leak. Low octane gas probably isn't helping.
I would top off the tank with high octane gas then get it out on the road and "burn out the carbon". See if you can get a can of race gas or aviation gas. Run it at high speeed to clean out the chambers.
You also need to make absolutely certain there are no leaking gaskets or poorly seating surfaces in the carb. Even new carbs can have internal leaks if a gasket isn't seating right.
Did you check for other vac leaks? There were a couple of times I left my PCV hose disconnected and the car did pretty much what you are saying. If you can get it to idle again start spraying propane near all the carb parts, hose connections and intake gaskets. I normally use starter fluid instead of propane, but if you are backfiring through the carb I would stick to the propane for now.
You might have gunked it up trying to make it run with the vac leak. Low octane gas probably isn't helping.
I would top off the tank with high octane gas then get it out on the road and "burn out the carbon". See if you can get a can of race gas or aviation gas. Run it at high speeed to clean out the chambers.
You also need to make absolutely certain there are no leaking gaskets or poorly seating surfaces in the carb. Even new carbs can have internal leaks if a gasket isn't seating right.
Did you check for other vac leaks? There were a couple of times I left my PCV hose disconnected and the car did pretty much what you are saying. If you can get it to idle again start spraying propane near all the carb parts, hose connections and intake gaskets. I normally use starter fluid instead of propane, but if you are backfiring through the carb I would stick to the propane for now.
