I just got done swapping my buddy's y8 from his 99 civic ex into my 97 Dx hatchback currently running a stock p28 ecu obd1 converted also used the wiring harness from the original y7

Got it running and it's running great but vtec isn't engaging I'm throwing the code 21 for the selonoid which I know was good because it worked perfect in my friends car...

Anywho it has an odd idling problem cold or warm it almost never wants to stay idling if it does it's barely above 500rpm I know it's not good that I have my iac blocked off and that's not helping matters but I've never had any no staying running problems blocking it off

Any clues?

 

why would you block your iacv?

 

My thoughts exactly! Your Idle Air Control Valve may be the issue........hum. Is the idle just going up and down or what exactly is it doing? As for the wiring harness you said that you swapped the engine harness correct? If not that DX harness will not have a wire for the VTEC so you will need to manually install a wire and hook it to the ecu and the other side to ground I believe. It's been a while since messing with that plug. As for the IACV do you at least have it plugged in? The DX would run a 3 wire plug where as that EX is going to use the 2 wire. Just trying to think of anything.

 

Sometimes the solution is staring you in the face.

 

I understand what the iac does it is just the fact that it idles so low I've blocked them off before and never had this problem

I am using the Dx harness still and ran my vtec wires and the one ground...

I was just asking if anyone else had similar problems

 

The IACV's sole function is to maintain proper idle speed. You have blocked it off and prevented it from doing its job. It's as simple as that.

 

just put a iacv on. i don't see why you'd even block it. what was your reasoning behind that? i'm kind of curious.

 

It was bad and I didn't have the 2 wire iacv plug just the stock 3 wire plug