Car doesnt' shut off
Thread Starter
Instructor
Joined: Nov 2005
Posts: 238
Likes: 1
From: Oklahoma City Oklahoma
Car doesnt' shut off
I have a 1980 L48 Coupe and when I turn off the car, the engine doesn't cut off immediately. It usually takes a couple of seconds like the carburetor wants to stay running, but will eventually shut off.
It doesn't do this all the time, but what causes it to do this at anytime?
Does anyone have a fix for me?
It doesn't do this all the time, but what causes it to do this at anytime?
Does anyone have a fix for me?
Drifting
Joined: Nov 2005
Posts: 1,795
Likes: 1
sorry i dont know what the secret is for a 4 spd.
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
It run-on. Usually caused by bad gas....watered down. Specifically low octane. Try switching gas stations.
Another cause is slightly over advanced timing or bad knock sensor(not sure if you have one).
Jim
Another cause is slightly over advanced timing or bad knock sensor(not sure if you have one).
Jim
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Lower your idle speed. If you have an anti-dieseling solenoid on your carb, set it up correctly and drop the idle speed screw on the carb so that the solenoid is holding the idle speed and cutting the throttle upon engine shut-off.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Whatever rpm is comfortable and that keeps the engine idling reliably. The rpm depends on the cam you're using. Run the lowest idle that keeps the engine idling consistent and reliably. For a near-stock application, you should be around 650 in drive. If it diesels, drop it to 600.
Last edited by lars; Mar 6, 2007 at 04:11 PM.
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Racer
Joined: Jan 2007
Posts: 253
Likes: 0
From: Winter Haven Florida
I can't exactly remember what my problem was when my car was dieseling, but it was either a vacuum leak or bad timing. Probably both in my case. Hope you find out what it is.
Josh
Veteran
Joined: Oct 2005
Posts: 1,284
Likes: 81
From: Nashville, TN
Mine used to do it and it was because the alternator and my coil wire were in the same circuit. They engine would diesel while the alternator was winding down. I ran a new coil power wire to the fuse box, put it on a 12v+ source turned on with the ignition key. Never did it again.
Racer
Joined: Oct 2006
Posts: 388
Likes: 3
From: Guyton, (Savannah) Georgia
I once had a car I put electric fans on the radiator. When the fans were running and I turned off the key, the engine would still run until the fans slowed down. The fans were sending voltage over the electrical system while they were slowing down and the HEI had enough voltage to keep going for a few more seconds.
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
Based upon the responses, I assume that you are experiencing run-on, where the car wants to turn off, but it stumbles around for a couple of seconds. If so, the above responses should be great.
However, you just stated that it keeps running. Is the engine stumbling after you try to turn it off, or does it run fine for a couple of seconds after you turn the key off? IF it runs fine, and just takes a couple of seconds to shut off, you may be looking at something else, such as the ignition switch.
However, you just stated that it keeps running. Is the engine stumbling after you try to turn it off, or does it run fine for a couple of seconds after you turn the key off? IF it runs fine, and just takes a couple of seconds to shut off, you may be looking at something else, such as the ignition switch.