Backfire when you let off the gas!

[kjbtsi6686]

I have a loud backfire when I let off the gas, am I looking at a exhaust leak? Or something more sinister, the exhaust isn't the best looking creation by a shade tree mech, I will post some pics of what I'm dealing with when I get a chance to not be at work.

[undysworld]

A backfire is a classic symptom of an exhaust leak. If you have leaks, fix that before you go looking further.

[pcolette]

Here's a photo of the original exhaust slip joint between the header pipes and the heat exchanger. This is a common spot for exhaust leaks.

IMG_2181.jpg (286.35 KiB) Viewed 3990 times

Many owners have replaced the slip joint with the flex kit from EI or SAV, like this:

IMG_2186.jpg (301.46 KiB) Viewed 3990 times

A good exhaust shop could also probably weld in some SS flex pipe for you if that's where the leak is occurring.

[kjbtsi6686]

Is this something I should be worried about as far as driving it?

[kjbtsi6686]

Looking at this exhaust it was done very poorly, I'll have to post some pics, the welds are horrible. I can see spots where there is holes in the welds.

[rmel]

Back fire in the exhaust could also be caused by improper timing,
insufficient tappet gap, or running too high an octane versus the
compression you have.

You can also get exhaust back-fire when you shift up/down as
in that case the manifold pressure increases (Negative Bar's)
resulting in a fuel rich condition with some unburned gases going
out the exhaust. If you have an EFI you can dial that problem
out with appropriate fuel vs MAP.

Might want to look at your timing and a compression check on
occasion is a well worth test -- trust me on that one from my
own experience

[kjbtsi6686]

Adjusted the timing (it was quite off) and she seems to run much better now. Looking at probably doing the SS muffler from EI soon.