Tarantula
15+ Year Contributor
- 209
- 5
- Feb 22, 2004
-
San Diego,
California
I'm sick of this. I searched and a few had this problem but never explained it it was resolved.
Heres the thing. When my car has oil temperature under 200F and I accelerate, around 5K I get a big backfire. After it hits 200F It does not happen. I checked for boost leaks, changed plug wires, changed from projected to unprojected 7ES spark plugs (NGK for both wires and plugs) replaced hoses, zipped tie hoses changed BOV and even changed boost and to no avail it always happen when the car is below 200F in oil temps. Also when the backfire happens my A/F does not go lean. Pretty much stays where it was as if nothing happened. I could keep accelerating and it will accelerate but in between it will backfire sometimes only once and other times twice but in every gear after 2nd.
My car has an external oil cooler. and so oil temps stay cool when I drive normal. The water temps stay around 200F all the time (i have a project I made on controlling this) To get the oil temps to increase I have to race the car. Any temps over 200F and its all good.
My car is far from stock so its not fuel cut. The back fire I'm referring to is usually called Afterfire. It comes out the exhaust and its violent. Its a big pop. It would even doit on part throttle and some boost.
I'm thinking that the fuel does not fully burn when my car is cool (combustion chambers since block temps are under 200F)and the gas come out into my SS exhaust (which retains heat really well) and boom, it ignites. I do run E85 in the mix as well.
Heres the thing. When my car has oil temperature under 200F and I accelerate, around 5K I get a big backfire. After it hits 200F It does not happen. I checked for boost leaks, changed plug wires, changed from projected to unprojected 7ES spark plugs (NGK for both wires and plugs) replaced hoses, zipped tie hoses changed BOV and even changed boost and to no avail it always happen when the car is below 200F in oil temps. Also when the backfire happens my A/F does not go lean. Pretty much stays where it was as if nothing happened. I could keep accelerating and it will accelerate but in between it will backfire sometimes only once and other times twice but in every gear after 2nd.
My car has an external oil cooler. and so oil temps stay cool when I drive normal. The water temps stay around 200F all the time (i have a project I made on controlling this) To get the oil temps to increase I have to race the car. Any temps over 200F and its all good.
My car is far from stock so its not fuel cut. The back fire I'm referring to is usually called Afterfire. It comes out the exhaust and its violent. Its a big pop. It would even doit on part throttle and some boost.
I'm thinking that the fuel does not fully burn when my car is cool (combustion chambers since block temps are under 200F)and the gas come out into my SS exhaust (which retains heat really well) and boom, it ignites. I do run E85 in the mix as well.
