1993 5.0

My car for the last 3 years has always had a little bit of back pressure noise(like a little backfire type noise) when the exhaust is cold, usually by the time I shift to 3rd or 4th it is gone, so once the exhaust warms up it goes away, Question is now it doesn't make that noise anymore, I know this may sound silly but I was just curious what would cause it not to do it anymore??

ttoppedaerocoupe

i wouldnt drive another mile if i was you, sounds like youre out of muffler fluid.

lookinforastang

LOL

just posting from my own experience when i got my new exhaust it had a mellow tone to it and withen 3 months it got louder and sounds "broken in".

i know u said u had it for 3 years i dont know man. u know ur car better than us. what have u done to it. u didnt really give any details.

1993 5.0

Where do I get that done at, the same place that refills your headlight fluid and puts winter and summer air in
your tires?

88BlueGT

Winter air and summer air... thats a good one I never heard that one before [sm=icon_rofl.gif]

PX429

What's your timing at? That can usually cause that popping noise in the morning?

1993 5.0

I haven't messed with my timing yet, so I'm not sure

1993 5.0

I see you got the car, I haven't been on to much lately, How is she running?

Twisted

So let me tell you what I've noticed. When I first get in my car (engine cold), I get the same sound on decel--like a faint backfire or puffing sound. Then when the car warms up, it's gone. This is what I think: When you first start the car, the thermactor system (smog pump) is pumping air into the heads. Then as the car warms up a bit, thermactor air is diverted to the exhaust. I believe (and some will probably call me silly) that I can hear the difference between when the thermactor is breathing into the heads, and when it's breathing into the exhaust. It takes a keen ear though. Whatever it is causing the backfiring (which is more like a "pft" sound) ceases at about the time the thermactor air is diverted downstream. It could just be a coincidence, but it sure seems to be the case.

Also, maybe your car is actually running leaner when cold, and causing the backfiring. I know that this happens with carbed motorcycles. Not sure about fuel injected cars though.

1993 5.0

Thanks I figured it was nothing but was just curious