engine swap probs.

ok so a frind and i bought an 89 rx. gtu. has 13bengine. it backfired alot when we bought it started driving home and he cant give it gas. has to let it idle home. =\. ok so we get it home and im think seals are bad, the engine ends up locking up wont do anything for a long time. we break it loose and its got a big miss now, wont idle cant do anything.
We buy a new motor, same motor 13b out of a 89 with tranny and harness. get it in and runs great. we drive home and it starts backfiring and spitting. we let it sit for a while started it and its fine for a while then shitty again. Ok now i have 2 big questions. 1. is there some kinda sensor that if not hooked up right sends the car into a safe mode that runs like shit?. or did we get screwed and buy a motor that needs rebuilt? any info would be great thanks =)

you might want to check the harness

and check if you put back the crank angle sensor, cause you can forget that easily

the harness was never removed from engine. we bought it as a whole set. was never cut but i will double check everything.

regardless of if it was cut or if it was intact, you need to check grounds and/or if everything's connected

Start by checking the coil igniters. It sounds like they are heating up and cutting out. Most likely the original engine was fine. The other thing would be a loose ground wire connected to the engine. Take a jumper cable and hook it from the negative to the engine. If it seems to run better, check the harness wires. Last, check the fuel filter. It could be plugged up and restricting full fuel flow.

Tim

well the car would just run like shit and go to i guess its called limp mode in mazda terms?. we hooked it up to a comp. and puilled ou a #27 code any ideas for that? the main relay seems to be working someone said check the oil meter pump wireing? and after that they said o2 was getting no reading.

27 is the oil meter pump. it connects to the front face place on the lower left side its got like 3 or 4 hoses comming out of it

ok so how would one go about testing this oil meter pump? as the o2 sensor had no reading also we replaced it. so now we kinda stuck on this oil meter pump.

take if off, put on a blockoff plate and run premix