hello i recently rebuilt my 92 civic vx with the 5 wire o2 sensor. the car had a full rebuild with new valves and seals. new head gasket, piston rings bearings ect. only thing not new is the iacv, vtec solenoid,map, egr, fuel pressure regulator and distributor. i replaced the cap and rotor and wires. and new plugs (ngk zfr5f-11) due to me being in central california a warmer climate and i will be commuting about 80miles for work a day. new cat, new ngk o2 sensor. timing is set to 16 degrees btdc. there is no check engine lights, and i have checked the egr system, which functions properly. fuel system and map sensor. all check out good. i have not checked the vtec solenoid. or the iacv but i dont think that would cause the issue. this is my first vx and i know they are temperamental. im wondering if this is just normal behavior like i have heard, or if i am missing something.

i also tried a spare 94 p07 ecu (4 wire) which threw the o2 sensor code. but it still ran the same.

im out of ideas. wondering if anyone has any ideas...

 

Try cleaning the EGR valve.

 

the egr opens fully when i apply 8 inches of vacuum. and when i apply the vacuum to the egr on the car it idles real rough. so using the fsm i have it would seem that its good right? i even checked the egr control box on the firewall and it also checks out...

 

when i unplug the vtec solenoid there is no change in idle is this normal?

 

I know when the vtec solenoid is unplugged it should throw a code. I once did some work to my d16z6 and forgot to plug the vtec solenoid and it threw the vtec solenoid code. Car ran normal though.

 

damn lol so not proof that this is my problem. mine does throw a code as well just no change in how it runs.

 

On a VX, VTEC doesn't engage until 2500rpm so I don't why you think unplugging it should affect the idle.





eH.

 

Try pulling each one of the plug wires while it's running (of course, with something that will keep you from getting zapped!) and see when/if the idle changes. If this works, it should at least give you a starting point if there is a misfire in one cyl that the ECU isn't picking up.

Just my 2 cents, if you didn't already try it...

 

i did try that. and they all effect it. so the mis isnt specific to a particular plug. the car was just painted and so the engine bay did get sprayed. im gonna check and see if maybe a ground isnt making a good enough connection maybe...

 

Can you give more details, and perhaps you can post a video. Does the idle problem occur when engine is hot, cold, or both?

Have you cleaned the IACV and FITV?

 

it occurs at both. and yes i have cleaned the iacv, but i do not believe the vx has the other sensor on the tb... i will post a video of the idle issue. i think it would help others in helping me. lol thanks for the brain storming so far guys.

 

Look again.

 

The again, you may not want to look again:

 

Describe the engine rpm behavior at idle. The video may help later.