"Diesels" when I shut down
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"Diesels" when I shut down
Anyone know what causes the car to continue to run after the ignition is shut off? I've adjusted the timing but that doesn't seem to make a difference. Have the idle pretty low (still does it). It's a "72" 454 engine that runs well otherwise but it just wants to keep running.
Thanks!
Mike
Thanks!
Mike
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From: Cape Cod, Mass.
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You shouldn't have to have your car in gear to get it to shut down. You are basically stalling it and not correcting the underlying problem. You said your idle is pretty low. What is it? High idle is the main reason for run on.
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
You mentioned that you have the idle set low. But, do you also have the throttle plates "set low"? If you are running ported vacuum advance your thermal efficiency at idle is crap. This requires more air and fuel for the same rpm. This then requires a larger throttle opening. This then leads to dieseling. (Note the term dieseling. There is no spark ignition required, hence adjusting your timing does nothing when the ignition is shut off.) If you have ported vacuum, change it to manifold vacuum, and then readjust your throttle stop (idle speed) adjustment.
If you already have manifold vacuum, then there are other issues. Let us know what you are running.
Race Director
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From: central FL, near the beach.
well i come back 15 minutes later it's STILL KICKING.
Funny with a co. car. Even so, that could blow the engine, so i put it in gear(stick). FF to C5's i read they rattle bad if left in neutral.
To park u must put it in gear, right? so shut it off, take foot off clutch. This is hard?
or switch to EFI, that works for sure every time.
Last edited by Matt Gruber; Jun 14, 2007 at 10:07 AM.
Instructor
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From: Lafayette Louisiana
Have you tried a higher octane fuel? Also; does it have the soleniod on the left side of the carb at the throttle? On my 71 it controls the idle and shuts the throttle plates closed when you turn off the key, but this may be on non a/c cars only.
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Reply
You guys are great! Thanks for the help..
I'm running a stock Rochester Quadrajet Carb, no solenoid on the side. I advancd the timing while installing a new distributor and it did increase the idle speed. I'll lower the idle to 800-1200 rpm and
see if that helps.
Thanks for all the input.
Mike
I'm running a stock Rochester Quadrajet Carb, no solenoid on the side. I advancd the timing while installing a new distributor and it did increase the idle speed. I'll lower the idle to 800-1200 rpm and
see if that helps.
Thanks for all the input.
Mike
Last edited by Mikeg72; Jun 14, 2007 at 11:09 AM.
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Re-read my earlier post. I already answered these questions.
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From: Cape Cod, Mass.
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2019 C1 of Year Winner (performance mods)
2017 Corvette of the Year Finalist
2016 C2 of Year
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You guys are great! Thanks for the help..
I'm running a stock Rochester Quadrajet Carb, no solenoid on the side. I advancd the timing while installing a new distributor and it did increase the idle speed. I'll lower the idle to 800-1200 rpm and
see if that helps.
Thanks for all the input.
Mike
I'm running a stock Rochester Quadrajet Carb, no solenoid on the side. I advancd the timing while installing a new distributor and it did increase the idle speed. I'll lower the idle to 800-1200 rpm and
see if that helps.
Thanks for all the input.
Mike
Burning Brakes
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From: Ventura California
Just a thought.... check your spark plugs and make sure they are not loaded with carbon. If they are, that carbon will glow like a cherry and provide another source for ignition aside from normal spark.
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Problem Solved
Thanks folks,
I drove to the local Sunoco gas station and put 1/2 tank of 260 in it (highest octane they have). And, lowered the idle way down and it shuts off fine now.
Thanks for all your thoughtful help!!
Mike
I drove to the local Sunoco gas station and put 1/2 tank of 260 in it (highest octane they have). And, lowered the idle way down and it shuts off fine now.
Thanks for all your thoughtful help!!
Mike
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Incorrect timing will cause diesling and here is how, if the timing is retarded then the idle speed will go down, now you turn the idle up to compensate and now the throttle blades are open to far when you shut off and you deisel 
