IAC valve + EEC relay ?

[lost86broncoii]

Hey guys, I just changed the IAC valve in my 86 ranger cause, the other day I unplugged it and there was no change in idle. I cleaned it out real good and still got no change, but when I put the new one on it, it ran better at first and when I pulled the pigtail it would idle down to around 650, hard to be exact cause the tachs been acting up too. But today when I was checking timing on the truck I unplugged the IAC again for shits and giggles and it didn't change the rpms. And when I went to shut the truck off the battery light was on in the dash, but the after market gauge was reading fine. So I was looking over the wiring diagram in my haynes(not the best I know) and it looks like the IAC gets power from the EEC relay and its also connected to the inertia switch(which some how got fried on this truck and is currently jumped with a wire). My question is could a faulty EEC relay or the wiring to or from it cause the IAC to mess up? I think I might change the relay or start looking for wiring gremlins.

 

[Earl43P]

If the EEC relay were bad, you'd have no spark, no start, no run.

You can check for 12v at the IAC connector and I expect you will find it present (key in Run, engine off). The PCM (EEC) provides a GROUND to operate the IAC.

What exactly are you trying to fix? If it's the Battery light, read the Tech library section on alternator.

http://www.therangerstation.com/tech_library/chargetroubleshooting.htm
http://www.therangerstation.com/tech_library/chargingsystem.htm

If your Battery Light goes out when you rev the engine, you don't have a "charging" problem, you have a low idle problem.

 

[lost86broncoii]

No I'm not terribly concerned about the battery light right now. I think your right on, its probably low idle, what I'm trying to fix is the truck has a bad miss under acceleration and I have been chasing it down for a while now, and this was just one of the things thats came up when checking timing to see if that was buggered... I got to go out and get a multimeter and check voltage and look for a ground. Thanks for the help.