I have an 89 civic DX converted to OBD1 with an OBD2 b20b motor. Using OBD1 LS ECU. I just checked my idle/air control valve, replaced it with a good one, checked my timing and the darn thing idles up and down. Please help, it is getting on my nerves.

 

No one has any ideas? I just need some ideas to look for. I just checked all my sensors and they are good. Could it be in the ECU?

 

do you have enough anti freeze?

 

that was the first thing I checked. I even did a complete coolant change and made sure it was completely full with no air.

 

could be a vacuum leak.

when does it idle up and down? all the time? when the car is cold? when its warm?

 

what tb are you using?

 

check your TB gasket

 

Whatever came on the 1997 b20b motor. When I first start the car it idles really high and then when it begins to warm up it starts the up and down idle.