Conversions & Hybrids - LS1 swap in Porsche backfire need help




rmj951
01-23-2010, 11:30 PM
I am wrapping up my LS1 swap into a Porsche 944 Turbo. On the dyno today we are having a backfire at 4500 rpm's.

The car idles & runs well but at 4500 we get the backfire. On the dyno o2 was 12 to 1 at WOT so it shouldn’t be a tuning issue. I was told to check for bad grounds. Any ideas?


remauto1187
01-24-2010, 12:34 AM
Ignition coil breaking down, spark plug wire.

I bet its not a bad distributor cap! :D

rao
01-24-2010, 08:03 AM
+1 on spark plug wires.


fast400
01-24-2010, 11:50 AM
Backfire through the exhaust or intake?

Bowtie70SS
01-24-2010, 12:30 PM
What about a bad valve spring? If it is broken near the bottom end it might not present itself until higher rpms.

rmj951
01-24-2010, 05:30 PM
We installed brand new wires & valve springs.

Bowtie70SS
01-24-2010, 05:38 PM
Maybe you have a bad fuel injector? What about your fuel and timing tables. Something could be goofed up there?