Backfire!!
 

why does my camaro backfire so much now that its cold? does it need to be tuned, or is it just cold and i shouldnt worry about it?[:o]

RE: Backfire!!
 

Which kind of back fire? Real backfire, such as flames out of the intake, or popping out of the exhaust?

RE: Backfire!!
 

popping out of the exhaust.

RE: Backfire!!
 

It's characteristic of LT1's to pop out the exhaust (note, this is very different from actual backfiring). It has to do with the ECU not being able to update the fuel mixture fast enough as the rpm's drop and thus you get a little bit of unburnt fuel in the exhaust that then ignites. Why does it do it more when it's colder *shrugs* maybe the colder exhaust pipes help the fuel condense, that I'm not entirely sure about. My car's exhaust is much sharper sounding when it's cold...it's fun enjoy it :D

RE: Backfire!!
 

thanks man, that makes a lot of sense cuz it does it less and less as the car heats up.

RE: Backfire!!
 

Another thing I thought of after I posted that, is when you first start the car it isn't running in closed loop mode, meaning it's utilizing the MAP sensor and the preset fuel trims in the PCM. Typically these settings are extremely rich, and thus you'll have more unburnt fuel in the exhaust to ignite. After the car heats up and goes into closed loop mode the computer can calculate the mixture on a dynamic basis.