Finally got my prelude running after doing a jdm h22 swap. It is running wierd now and i think it has something to do with the vacuum lines. It is bogging out at idle and jumping. when i play around with the vacuum lines it seems to fix itself. I was wondering where the intake control diaphragm is located(i see it in helms but not on car). Also can the black box under the intake manifold be eliminated?

 

hey what up man!!! i just did the same swap on my 4th gen and it had the same symptoms like yours. I found out the problem on mine though. its the EGR valve that was defective. Currently it has a block off plate there and it runs at 100% I'll be getting the valve today so I can slap it on and pass smog. Thats my .02 cents there so good luck man...

 

How do u have your vacuum lines hooked up? Because one of the nipples on the black box is broke on my car....was gonna try and avoid hookin it back up if i can......i dunno man just got car on road and this is kinda disappointing. Hope its an easy fix

 

Well i took ur advice ......i changed my egr valve. That worked for a little bit til i got around the corner...then right back to square one again. maybe i should try a blockoff plate. Also i got cel code 21 and 23....23 is knock sensor. Anyone know what code 21 is?

 

code 21 is vtec solenoid. are you sure its plugged in and wired properly all the way to the ecu?

the black box under the manifold is the vacuum canister and solenoid for the iab's.
the intake control diaphragm, aka the iab diaphragm, is powered by the iab vacuum canister and solenoid. the diaphragm is on the drivers side of the intake manifold, its the big round thing near the edge of the plenum that has a vacuum line connected to it, which should run down to the solenoid below the intake mani on the side of the black vacuum canister.

what ecu are you using?

 

im running the ecu for the h22...not sure if its p14 or p13(dont remember the number thing its been a while). but yea i didnt run the wiring yet for vtec yet. I was planning on running them after the weather breaks and when i got the engine going good. Would this have an effect on how the motor runs if i don't have vtec wired in yet and drive it how it is?

 

well man the right ecu that you should have on is the p13. what i've notice man is that with honda's its always an easy fix. it has to be a sensor. Take it to someone that knows honda's. Tell him to go over the job and to make sure everything is plugged in correctly. that is what i did and he charged me 2 bills to check everything, wire vtec the legit way, fix my rpm tack (it wasn't working) and fix my idle issue by putting the block off plate. although its 2bills it was a good investment cuz in a day he had it up and running at 100%

 

Sounds as simple as a vacuum leak. Check for cuts in vacuum lines or leaks along your intake. Maybe even intake manifold gasket around the block.

So by jumping you mean the idle correct? Any other symptoms you can tell us? How does it accelerate when you push the gas?

 

Well i made a custom egr blockoff plate. Seems to run a little better with it. Its idling a little higher with it on tho. What am i supposed to do with the egr sensor when i remove the egr valve, and the vacuum line that goes to it?

Yes and it is the throttle that is bouncing around. When i hit the throttle the car sounds like a motorcycle.but if i hit it lightly sometimes it sounds like it should. Has to be a vacuum problem.