Motor breaking up...also backfiring alot

[RacethisTSI]

A few days ago i was driving and downshifting. i was going to rev match and the car just started backfiring and then stalled out..got it running one last time and then it died for good...At the time i checked for spark and it was good. I also checked compression just in case timing jumped...160 across the head. i then took off the fuel return line to see if i was getting fuel...there was nothing coming out... so yesterday i putt in the walbro 255 i bought and now i have plenty of fuel...the car started and ideled very rough...so i took it out for a quick drive...ran a little rough but alright. After the car warmed up i went to get on it and again the same thing...it started backfiring and breaking up. i backed off and it was fine...went to tryed it again and same thing happened, but then it stalled out and wouldnt start again...im maybe thinking it could be a map issue or the ignition moduel... but ide like to get some input before i go buy anything...

 

[DSM90AWD]

Were any CELs thrown when it started acting up?

I'd first check for major intake/boost leaks, including ensuring your MAS/BOV are properly connected.

When you said no fuel was coming out the fuel return line was the car on and the pump running? If during initial key-on, it takes a couple secs for the pump to fully pressurize (prime) the line and the FPR should be holding most of the fuel up to that point and then release anything > 42psi at ambiant pressure. The 255 is much quicker to prime so the delay would be much less noticable.

FYI.. when strange fuel/ignition problems come up I always take a look at the ECU to make sure that there are no leaking caps or burn traces on the board

 

[RacethisTSI]

i didnt notice any CELs. and no i was turning the motor over when i was checking for fuel pressure. thanks for the input ...ill check my ecu and get back.

 

[RacethisTSI]

i checked my ecu and its fine...i dont thnk it would be a boost leak...im just not getting spark