I have a 94 hatch with b20b swap that I bought already completed. It's never ran right. Basically it falls on it's face under a load, backfires under hard acceleration won't get past 4000 rpm, backfires and jerks during deceleration and smells like fuel. I've tried different ecu cuz I was told It could be that, tried new fuel pump new injectors new maf sensor ica distributor nothing changes. Then I was talking to a friend at work who had a similar situation in his 240 after 2 years of trying to figure it out it ended up being the knock sensor. So I did some research and found out that the jdm b20 doesn't have one but my car is still running the factory p28 with what I assume is a shity base map. Basically my question is could my ecu be looking for the knock sensor that is non existent and causing my issue and what is the easiest solution for fixing it. Please help me I've been trying to figure this out for almost 2 years and I'm guessing the person who owned it before couldn't figure it out either and is why they sold the car.

 

The OBD-1 P28 does not have a knock circuit, so this is not your problem. You said you have a chipped P28, but you are unsure of the quality of the map. I suggest you find a P74/P75 OBD-1 ECU and try it. No knock sensor and has the closest mapping to a B20B engine in stock form.

Next, you need to make SURE that your mechanical timing (timing belt, cam gears and crank gear) is dead on, your distributor ignition timing is properly set to 16' advance, and set your TPS to .500v while the key is on but the engine is not running. You didn't mention any CEL's or codes... so I am assuming that you don't have any. If you do, diagnose and fix those before you do what I have suggested above.

 

I've had the timing checked by 3 different people all telling me it's good and there is no check engine light. Do you have any suggestions on what could cause the symptoms I'm having. It runs fine until you give it a lot of gas then it starts missfiring and rpms won't climb. Or should I just try getting the ecu you mentioned, and thank you for the help.