Turning over after ignition is "OFF"
Thread Starter
Burning Brakes
Joined: Sep 2001
Posts: 986
Likes: 0
From: Raleigh NC
Turning over after ignition is "OFF"
My engine sometimes turns over a couple of times, stutteringly AFTER i turn the ignition off. Someone told me it could be bad timing. How can i check and or fix this? Thanks!
Burning Brakes
Joined: Aug 2000
Posts: 984
Likes: 1
From: Cincinnati OH
Re: Turning over after ignition is "OFF" (scorciae)
With carbed cars like your '80, sometimes carbon build up in the chambers combined with low octane gas would cause this (called "dieseling"). Try switching to a higher octane gas like scorciea suggests, or at least a different brand of gas. I don't see how it would be the ignition timing, once the key's off, so is the spark.
Pro
Joined: Jun 2000
Posts: 698
Likes: 1
From: Park Ridge IL
Re: Turning over after ignition is "OFF" (Jenny)
Sometimes I have the same problem. When the car is all warmed up than it tends to do that. What I have started to do, is to shot it off when in gear (auto), it's in lower rpm's and it's shots right off w/out "turning over".
I do use only the 93 octane gas.
Ziggy
I do use only the 93 octane gas.
Ziggy
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
Re: Turning over after ignition is "OFF" (Vince Ivanc)
Vince - you don't need a spark to ignite the mixture. The plugs may be hot enough to glow & that will light the mixture.
Usually this happens when the timming is too far advanced & combustion chamber heat is high. You turn off the motor & the glowing plugs will lights the mixture. Usually the motor runs/kicks backwards when this happens. I had a truck this happened to - the motor actually ran backwards at an idle speed for a few moments. It destroyed the carb when it caught on fire.
A quick way to fix this for now is to shut off your car in gear. If it's an auto - put it in drive, if manual - put in 2nd & slowly let the clutch pedal out while your holding the brake. When the rpms begin to drop with the load, turn off the key.
[Modified by 71coupe, 10:03 AM 12/7/2001]
Usually this happens when the timming is too far advanced & combustion chamber heat is high. You turn off the motor & the glowing plugs will lights the mixture. Usually the motor runs/kicks backwards when this happens. I had a truck this happened to - the motor actually ran backwards at an idle speed for a few moments. It destroyed the carb when it caught on fire.
A quick way to fix this for now is to shut off your car in gear. If it's an auto - put it in drive, if manual - put in 2nd & slowly let the clutch pedal out while your holding the brake. When the rpms begin to drop with the load, turn off the key.
[Modified by 71coupe, 10:03 AM 12/7/2001]
Team Owner
Joined: Mar 2001
Posts: 30,858
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From: Boston, Dallas, Detroit, SoCal, back to Boston MA
Re: Turning over after ignition is "OFF" (71coupe)
You car is dieseling, since it's not a diesel that's not a good thing.
Either a higher octane fuel, or a lower compression!
Either a higher octane fuel, or a lower compression!
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Le Mans Master
Joined: Oct 2000
Posts: 8,897
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From: Santa Ana CA
Re: Turning over after ignition is "OFF" (Jenny)
Checking the timing may help with knock while the engine is turned on, but think about it, if the engine is off, the plugs aren't sparking so timing is not an issue at that point. If your compression ratio is less than 10.5:1 and your heads and plugs aren't full of carbon, the answer is "don't use cheap a-- gas." Besides, anyone who puts anything less than premium in a Corvette shouldn't be driving a Corvette.
Safety Car
Joined: Feb 1999
Posts: 3,631
Likes: 14
From: Fountain Hills AZ
Re: Turning over after ignition is "OFF" (Jenny)
In addition to the good advice already given, a high idle speed can also contribute to "run on". The combination of heat from sources already mentioned, low resistance to movement from low compression, and the increased momentum from higher rpm can allow the engine to continue running after the ignition is cut.
