bad gas?

[kuruption109]

ok guys so i changed my thermostat and flushed radiator thinking that was the reason my car was doin that weired thing when you cut it off and its wants to stay on... dont really know how to explain it but i was told it coul be ba gas and car not running hot so can anyone help!!!

 

[Blake442]

You mean it stays running when you shut the key off?

I'd look at the ignition system for gremlins.

 

[kuruption109]

You mean it stays running when you shut the key off?

I'd look at the ignition system for gremlins.[/ ill record a video tomorrow an post it.. i cant reall explain it...

 

[patmckinneyracing]

I think you're referring to detonation. Basically the motor sounds like it's still igniting gas in the piston chamber a second or two after you turn the ignition off.

I had this problem with my motor when I first built it. It was a matter of timing adjustment for me. I don't know what the cooling system would have to do with detonation unless you have a cooling issue, but if the engine stays below 200* degrees then it won't cause detonation.

Bad gas is a possible cause. What octane gas are you putting in the car? Now that most gas stations are adding up to 10% ethanol, some of us may start to see gremlins coming out of the wood work if our engines don't like the additives.

 

[kuruption109]

regular unleaded lol think that 87... shoul i upgrade to better gas?

 

[patmckinneyracing]

Yes you should. I started using premium 93 octane in my 350 and that definately helped cure the detonation. That along with timing cause I think detonation can occur if your timing is too advanced.

 

[bjohn07]

usually dieseling or engine runon. is caused by timing being off, or it could be caused by incorrect idle or your carb leaking fuel into the intake. but usually its timing. i would check that first.

 

[MR442]

I read that the new gas is only at its best for 12 days and goes down hill . Thats way they are coming out with all the aftermarket additives for it .

 

[bigjoenvegas]

usually dieseling or engine runon. is caused by timing being off, or it could be caused by incorrect idle or your carb leaking fuel into the intake. but usually its timing. i would check that first.

Timing is off or the idle might be off just a little. You just re-did your tank and re-built your carb so I don't think it's bad gas unless you got that cheap Arco am/pm gas. I try to stay away from 87 and go with the mid grade gas in all my cars. Check your timing and maybe your vacuum lines. My old 6 banger Cutlass used to do the same thing but it was a beater, so it didn't bother me too much.