Jvs10

Hey all. We did a d15b head swap on my 92 Dx and the idle is pretty erratic. When I fire it up, it idles up to about 2500rpm and then drops to 1000 and just does that over and over. When it warms up, it does the same thing just between about 900 and 1500rpm. We switched the IACV from my d15b7 head onto the d15b head because it had an extra vacuum connection on it. Could that be the problem? Maybe the vacuum lines on it are backwards? I ran it with a p06 for a few days, it didnt have the idle problem with that. It did run like crap though. I have a p28 in it now. The temp gauge also stays bottomed out. When we first did the head swap, I was throwing a cel for the temp sensor, turned out it wasn't plugged in. I have no cel now, but I have no gauge. The fan kicks on when it warms up. There is an extra plug on the head, next to the temp sensor plug. Its circular. I dont have this plug on my harness. Should I swap over the z6 harness off the other car? Thanks in advance

pdiggitydogg

Lets start with: Did you bleed the coolant?
Where are you pulling vacuum? Are you sure its not leaking?
We will tackle the ecu bit afterward basics are addressed

Evs-One

the one pin sensor on the head, next to ECT is for the temp gauge.

Jvs10

I the IACV is the culprit. My friend blocked it with his finger and the idle stopped fluctuating. I'll swap the old one on and see if that helps. I cant find the plug on the harness for the gauge. I'll dig around for it tomorrow when I have light