Only about 20% of the time when I turn my car off the engine sounds like it is coming to a stop, and then it sounds like it is turning back on again. After about a second it turns off. Any idea what would make it do that? Mind you the key is in the off position during this time?

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1984 Z28 Camaro
Mods: 350 ci built by Ultimate Performance Inc, 4 bbl Quadrajet rebuilt by Holley, 700R4 Rebuilt by Level 10, Hyptertech chip Stage 2, K+N air filter, Edelbrock TES exhaust manifold, Flowmaster Muffler, 3.73 Richmond gears, Auburn Posi Limited Slip Differential, KYB Shocks and Struts, Edelbrock Panhard Bar, Trailing Arms, and Strut Tower Brace, TRW Springs, 245/50/R16 Embassy Tires(Yeah, I have no more money.)
Future Mods: Paint!



[This message has been edited by watchmesuck (edited August 02, 2001).]

 

Sounds to me like she's dieseling. Two things cause this . . . High idle and a dirty combustion chamber. The heat of the engine keeps it running without spark. A dirty combustion chamber stays hotter (all that carbon) while a high idle lets enough gas in to combust. Hope this helps.
Oh yeah, this only happens with carb's

[This message has been edited by Truckman (edited August 02, 2001).]

 

Thanks, I'll try to take a look at that.

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1984 Z28 Camaro
Mods: 350 ci built by Ultimate Performance Inc, 4 bbl Quadrajet rebuilt by Holley, 700R4 Rebuilt by Level 10, Hyptertech chip Stage 2, K+N air filter, Edelbrock TES exhaust manifold, Flowmaster Muffler, 3.73 Richmond gears, Auburn Posi Limited Slip Differential, KYB Shocks and Struts, Edelbrock Panhard Bar, Trailing Arms, and Strut Tower Brace, TRW Springs, 245/50/R16 Embassy Tires(Yeah, I have no more money.)
Future Mods: Paint!



[This message has been edited by watchmesuck (edited August 02, 2001).]

 

How about timing??

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(Gran Turismo Americano) "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber) & AC Delco Rapid Fire Plugs

 

Also, check to make sure you arent running too rich. My old lg4 would do this when the mix control solenoids went out. They would make the car run full rich (wot setting) and just dump gas into the engine at idle and it would diesel for up to 15 seconds sometimes.

 

Check the timing first.



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1992 Camaro Z-28 5.7L auto t-tops arctic white

1967 Pontiac Catalina 2 door fastback 400 v-8 auto cameo white dark red interior

 

cheap gas can cause it too, when I was using 85 octane my car would always diesel, the lower octane rating has a lower flash (combustion) point and can keep igniting for awhile even with the key off. This is especially true of high compression cars. In fact, if you look at diesel fuel it is very low octane and diesel engines ignite by compression alone, no spark.

Anyway, I started going to a place that has 10% ethanol by volume in their gas so for the same price as 85(sometimes less) I could get 88 octane and I've never had it diesel with that stuff.

 

How does the timing cause this problem? I'm not asking to challenge your answer, I would like to know in case I encounter this in the future. Does the timing cause more carbon buildup or something? Thanx

 

Since I am just now getting really into cars, what does WOT mean?



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1984 Z28 Camaro
Mods: 350 ci built by Ultimate Performance Inc, 4 bbl Quadrajet rebuilt by Holley, 700R4 Rebuilt by Level 10, Hyptertech chip Stage 2, K+N air filter, Edelbrock TES exhaust manifold, Flowmaster Muffler, 3.73 Richmond gears, Auburn Posi Limited Slip Differential, KYB Shocks and Struts, Edelbrock Panhard Bar, Trailing Arms, and Strut Tower Brace, TRW Springs, 245/50/R16 Embassy Tires(Yeah, I have no more money.)
Future Mods: Paint!

 

WOT = Wide Open Throttle




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1985 Camaro SC - 2.8L, auto.

http://www.xenodrgn.f2s.com/Frontright.jpg

 

check for vacuum leaks too. My friends 85 TA was having this problem, turned out to be a vacuum line i "thought" i had plugged, but didn't.

Eric

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My 1986 Z28
GM350, T-5, 3.23's, lots of go fast goodies, 4th gen Firebird interior etc...
85 IROC w/ 1364 miles!

You'll always find what you've lost in the last place you look

R.I.P Dale Earnhardt