91 se-r w/ a u13 swap. My car runs rich and is currently running the stock se-r ecu/maf. Today my buddy and me switched out the stock ecu/ maf for the u13 ecu/maf, but the car doesnt idle well and runs so rich you can see black smoke out of the exhaust. What could be the cause of the car running so rich? It just doesnt make sense to me that the motor doesnt run properly on the ecu and maf that is supposed to be used. How is it possible an n/a ecu/maf runs the boosted motor better than the u13 combo?

What injectors are you running?

C

stock u13 370's....everything is stock except for a frontmount and walbro 255....i was thinking maybe the stock fpr cant regulate the flow of the walbro well enough so its running rich?