torose

I have stock crate 2006 LS2 in my 67 Corvette and experiencing backfire through exhaust and some forum members indicated to check for vacuum leak.

I check my MAP sensor reading and it showing 10.2 in at idle. Is this low as I seen some info that it should be around 20 in?

Thanks

DJJONESIVS

I might be a little bit of fuel exploding in the exhaust/ header.

torose

Thanks for the response and that seems to be the issue. I was told to check for vacuum leaks or exhaust leaks.

On vacuum side, I'm using the vacuum port on the rear of the engine for my PB and the only other place I know(still learning about LS) was checking MAP. Wasn't sure of operating range of MAP is or what should vacuum reading be for LS2?

The exhaust is stock manifolds using dual exhast and I don't have leaks there. I understand on C6 that using H or X pipe has helped backfire issues but I'm running straight exhaust.

edcmat-l1

When does it backfire? On decel? If so, this can be tuned out. Either greatly reduced or completely eliminated. I can do that for you through mail order for a small fee. Send me an email if you're interested. Email addy in sig.

torose

Sent you an email, that is exactly what it is doing. Let off accelerator, it gets down to around 1800 rpm and starts popping.

Thanks for the help

h8bumps

The solution is to change your DFCO entry and exit spark settings -- they cut the spark advance aggressively right around 1500 RPM during deceleration, and that's what causes the popping.