I have a 90 hatchy with a B series swap. At first I put in a b18a and it ran fine. The motor was smoking so I swapped it out to a b18b. It would rev up and down all the time and I couldn't figure it out. I changed the iacv, the tps sensor, the map sensor and everything else I could think of. Finally I took the car to my boy and he unplugged the map sensor and it runs fine. Could this be a wiring problem or what?

 

you need to throw more info in here. Is it still obd0? are you getting a check engine light? if so what is the code? have you installed anything lately?

 

maybe a bad map or it is hooked up wrong

 

its a bad map sensor... or make sure you dont have the tps and the map sensor plugs crossed they are the same and can reach each other

 

plug your map back in and hook up the vaccum line on the back of the intake manifold i had that same problem with my gsr. unlplugging the map sensor works for a while but eventually it will start doing it again.

 

It is still 0bd0 and I changed the map sensor already. When I have the map sensor plugged in its throwing codes 3,4,5,7,9, when the map sensor is unplugged its throwing codes 3,9. I would like to get the car running smooth. Its a pretty alright looking car and it was kinda rough putting the car together. Its my first real project car and I want to get it rolling. Will be posting pics soon.