ok i just bought a 97 honda civic ex. The body is in great shape. beautiful car. the civic does not have the factory motor(b16)? ok its has a d15. huge downgrade i know. my goal is to get the d15 running good to drive back and forth to work and stuff. The wiring harness is out of a 92 civic. i check about that at a race shop they said it was common for people to take older civic wiring harness and use in a newer model. True? The d15 has a gas reg pressure valve on it ( on a stock motor?) the major issues that is botherin me is when i rev to 1500rpm to 2000rpm it sticks and sounds like a rev limter?? it will rev up and down between 1500 rpm to 2000rpm. and my timing is outta wack the distbor was turned all the way down. ( spraying?) so i tuned the dist. back to normal and the idol is sitting at 1500 rpm when motor is warm. maybe a few teeth off on the timing belt? my goals are to fix the d15 so it can run normal for a daily driver then save money to put a b18 in it ( Outta the del sol)? b18 is a strong motor and can with stand the punishment with high perfromace parts correct? any one help me with my issue? thanks.

 

The original engine was likely a D16Y8. What ECU are you running? Is the CEL ON? Have you tried to retrieve CEL codes from the ECU (see CEL link in my signature).

Regarding the high idle, check whether the throttle cable or plate is sticking. Also try cleaning the fast idle valve on the throttle body. It may not be closing after the engine is hot. Also clean the IACV, and check for intake air/vacuum leaks.

 

You're on the right track, confirm that you have the proper ECU. The harness and ECU should all be matched to the engine type. Note that swapping to an engine that is older than the car is generally not allowed under smog laws and the car will probably not pass a smog test.

The CEL should come on for 2 seconds then go out when you turn the key on but don't start. If it doesn't do that someone has disconnected it so it won't come on when a problem is detected. You will need to get it working because trouble codes are read out via the CEL.

Check cam and spark timing, and check for stuck throttle or vacuum leaks. Any excess air entering the intake manifold will cause idle to speed up.