so my friends got a 89 hatchie with a b2 mpfi swap. a6 intake and tb and engine harness. All wiring is legit, its in time, and its actually cranking and running. bogs down under WOT and ever so often backfires through the intake and actually shoots a small flame lol, lean mich? so come to find out hes running a pm8 ecu (hf). So from what ive read the pm8's are pretty much worthless to this set up, what with the different air/fuel ratio, the egr pins....and no egr on the a6 lol. Is this what is causing this dudes issue? Id really like to help him get his car running for IFO this sunday.

 

so this car was a dx but swapped to mpfi? for one that ecu is not gonna run that motor very well so getting at least a pm6 is a good start. and did you swap the 2 wires around at the tps plug? red and green

 

backfiring thru the intake is usually a timing issue - firing order incorrect or ignition timing or camshaft timing waaay off

 

Bogging sounds like it could be TPS wires not changed like HH says above.Backfiring sounds like timing issue somewhere.
You do want to get a better ECU than the PM8 though but I don't think it will solve all your issues.

 

ran the pm6 its doing the same thing. Ive checked the timing from cam to crank its dead on. Reset the dizzy timing, nothing changed, and yes the tps wiring was switched. IDk what are the chances that the engine harness is garbage? cause ill reclear the ecu and it will start to throw random codes sometimes.