Bad Cold Idle

[nickrahn]

The ol explorer seems to not wanna idle on cold start up. it will start and the idle will pulse and eventually die, I could restart it 10 time when cold and it will keep stalling. I thinking throttle position sensor, EGR or Idle Air Control Valve. can anyone confirm before I spend the money? It seems to run fine after warm up.

 

[MrShorty]

Unless Ford did something really weird with your '92, it won't have an EGR system so I wouldn't think the EGR is a possibility.

TPS or IAC could be a possibility. If it's the IAC, it's more than likely just dirty rather than in need of replacement. TPS is a simple potentiometer and can be tested easily enough.

In addition, a dirty MAF could cause those symptoms, or a fuel delivery issue, or a vacuum leak, or who knows what else. Before I started spending money on parts, I'd spend some effort in diagnosis. I'd probably start by pulling codes (see stickies in EEC-IV forum) and checking fuel pressure on initial startup.

 

[nickrahn]

I cleaned the MAF sensor and I did the CEL tests. Key on engine off, 111, 124, 157, 158. and Key on engine on, 412 was it. after the test I cleaned the MAF sensor. did not test again to see if it helped. the 124 code was for the TP sensor. so I was thinking that's why it was in need of a changing.

 

[nickrahn]

uh

So I was curious, I unplugged the idle air control valve and there was no difference. so I took it out and I find that it has wet black stuff in it. Carbon or oil I suspect. so I cleaned its insides and wire wheeled the outside to make it pretty again then reinstalled it. I also gave the idle adjustment screw a few turns to raise the idle and it seems to idle without stalling now at about 500. it seems to be rough still though.