Hello, I have been trying to diagnose this problem with my swap for the past few days. Originally the car would start up and idle at around 2000 and then drop to 1500 and surge back and forth the 1800. I replaced the spark plugs with NGKs and replaced the wires with some bosch ones. I took off the FITV and cleaned it and tightened the screw back down and this seemed to help significantly. The car now starts at about 2000 rpm and will drop down to 1000 rpm and hold it. However when I give it a bit of gas it pulses for a couple seconds before dropping down to a steady 1000. If anyone has any insight on how to fix this that would be greatly appreciated.

Sry. 93 Civic VX with a 94 B18b motor

 

thank you for stating the Y,M,and M of the car

first double check to see if all your vacuum hoses are where they're supposed to be on the IM and if everything is kosher with those...
try cleaning out your IACV with some brakekleen

 

Check all ur vacuum lines, clean your IACV and lastly check ur TPS...

 

also check u intake manifold gasket. I was having problems with my idle too. I cleaned everything and still nothing. I changed the gasket and it runs nicely now. Easiest way to check for a leak there is take some carb cleaner and spray it on the gasket at each cylinder. If it just dies then theres your problem. Might not be your problem but it was my cars problem.

 

Ok, thanks for the replies. I just stumlbed on a good how-to for the IACV, so I will give that a try. I am not pulling any ecu codes and the motor is completely stock. It could possibly be a vacuum leak I couldn't find. I highly doubt it is the intake manifold gasket because this hasn't been removed and has only been touched by the honda manufacturing plant to my knowledge.

 

Ok everyone, I cleaned the IACV and the car is running like a gem for the most part. It starts up cold at 1500 steady and then slowly drops to 800 when it warms. There is one thing that I am not liking about it though and it could be due to a lightweight flywheel. The problem is when I rev it up and let the engine slow down to idle the revs drop below idle for a second down to say about 500 rpm and then up to a steady 800. Once again I feel that perhaps the flywheel could be the culprit. However, any insight on this problem would be greatly appreciated.