Backfiring????

[86ttopmustang]

im new to mustangs but when i get on my car hard (about 5500rpm) and shift the car backfires (once in a while)...im lost where should i start????timing?ignition?

thanks

 

[stangincoupe89]

theres an number of things that coupld make it backfire. such as the plugs, wires, distributor module, cap and rotor, or the timing. im sure its one of those thigs. good luck.


1989 coupe with everything u could imagine

 

[Shakerhood]

Usually its timing related, I am surprized the intake manifold survived after backfiring through it at that high of an RPM!

 

[HISSIN50]

Based upon what you said about it occuring during the shift, it sounds like a rich backfire. When you let off the gas for a shift [after being at high RPM/high load], the motor goes rich for a split second as you get off the gas real quick for the shift.
The EFI actually normally does a great job of dealing with this, but a glitch in tune or mods can allow it to happen (and it's more pronounced with an O/R pipe).

Good luck.

 

[Shakerhood]

Based upon what you said about it occuring during the shift, it sounds like a rich backfire. When you let off the gas for a shift [after being at high RPM/high load], the motor goes rich for a split second as you get off the gas real quick for the shift.
The EFI actually normally does a great job of dealing with this, but a glitch in tune or mods can allow it to happen (and it's more pronounced with an O/R pipe).

Good luck.

I agree with you that the modern EFIs do a great job in correcting. I still have a hard time thinking the Intake Manifold survived a 5 Grand plus Backfire! Last time I changed my air filter I cleaned out my airbox good with some Isopropyl Alcohol and I got a quick Afterfire as soon as I started the car.

 

[poneypower89]

I agree with you that the modern EFIs do a great job in correcting. I still have a hard time thinking the Intake Manifold survived a 5 Grand plus Backfire! Last time I changed my air filter I cleaned out my airbox good with some Isopropyl Alcohol and I got a quick Afterfire as soon as I started the car.

Umm.. why would the manifold be hurt?

If the car is running too rich then fuel is dropping through the exhaust valve and landing on the heated up headers... in turn the fuel is ignited in the headers and a fire shoots through the exhaust system.. backfireing ...

 

[Shakerhood]

Umm.. why would the manifold be hurt?

If the car is running too rich then fuel is dropping through the exhaust valve and landing on the heated up headers... in turn the fuel is ignited in the headers and a fire shoots through the exhaust system.. backfireing ...

Umm... Because the Definition of a "Backfire" is out of the Intake System, and the Definition of an "Afterfire" is out the Exhaust System!

 

[HISSIN50]

Sorry for the ambiguity - PP89 hit what I was getting at on the head. The unburnt fuel (From the throttle blade closing all of a sudden and causing the rich condition) hits the exhaust and pops. Cats kinda help quell the noise (hence being more pronounced with an O/R).

I see where Shaker is comin from though - it sounds like he has worked on composite-intake cars and those scare me as well.

 

[86ttopmustang]

im sorry i thought backfiring was out the exhaust...my fault the car will afterfire sometimes(sorry for the confusion)

 

[Zero_chance]

Almost everyone uses the term backfire for burning out the exhaust. And for the intake. Its just one of those things.

 

[86ttopmustang]

alright now that the name is solved what should i try to fix it?????