Running L15A with L12A2 ECU
 

I have swapped a old L12A2 engine (had low compression in two cylinders) with a junkyard L15A (compression 180+ in all cylinders) . Tranny is CVT.


Both engines have same bore but L15 has a longer stroke. Could this cause an issue for the old ECU???


As per my understanding ECU would decide when to inject /ignite fuel based on CKP sensor output so longer stroke should not make any difference


All wiring connections from old wiring are grip to grip fit on the new L15A. Only the EGR valve is left unconnected because the old wiring did not have EGR support.


There is no check engine light. Only problem I am facing is
- slight misfire heard from exhaust at idle.
- slight jerking when accelerating between 80 to 100 Km/h
- slight delay in movement when gas pedal is pressed at car stopped

can you get a cheap obd2 connector to data log? Can you check the % throttle body open reading at engine off with 0 pedal and then fully pressed? Does it change immediately? Have you verified the items that would cause these issues on a stock motor are good to go (good coils, spark plugs, valve adjustment). Have you blocked off the EGR port? I'm trying to picture it in my head but that could cause minor issues depending on what state it sits in on your car. A block off is incredibly cheap - get a piece of sheet metal, cut with tin snips and bolt on using stock bolts.