Ask technical questions about your Ford Bronco II here. Technical write-ups on your axle swaps, engine swaps, chop tops, etc. are encouraged.
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Joined: Wed Dec 28, 2016 12:38 pm
Location: Loganville, GA


Postby 2ruble » Wed Dec 28, 2016 12:43 pm

I've seen some idle threads and some have helped. I'm new to the bronco ii scene. I've had my 89 b2 for a little over a month. I found the IAC unplugged (and not working) and have replaced that, the check engine light was on for intake air temperature sensor unplugged, found that and plugged that back in and now once warm it idles about 1,500. On start up it'll idle about 900, which I feel is normal, but once warm it now holds about 1,500 (was holding at 2,100 before above fixes).

It appears as though the valve covers are leaking and my PCV grommet is slightly warped and the blow by cap doesn't seat properly. I was wondering if there were any other ideas or if one of the latter mentioned could. E the culprit?

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Joined: Wed Dec 28, 2016 12:38 pm
Location: Loganville, GA

Re: Idle

Postby 2ruble » Wed Dec 28, 2016 3:22 pm

Update: it idles fine on initial start up, once warm it all of a sudden idles up to about 1,500. While coasting to a stop it holds idle around 1,900-2,100 until I come to a complete stop then it idles down to 1,500-1,600. I have to press and slip the clutch to let it idle down to about 1,100-1,200 to go from stop. Between shifts the idle drop is slow, real slow...

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Re: Idle

Postby tekatlarge » Sun Jan 01, 2017 11:46 am

My first thoughts are what codes do you still show in the computer? It sounds like possible bad exhaust oxygen sensor.

Things to look at are

1. EGR Valve,
2. oxygen sensor,
3. how much vacuum
4. Ignition timing (Checked with Spout disconnected),
5. Oh and 1 more thing, the computer temperature sensor. not inlet air temp! you want engine water temp.
also look for possible air leaks, around the IAC.

I can't remember off hand if the BII has 2 temp senders, 1 for the computer and 1 for the gauge. You might want to check the temp sensor as that will really play heck with idle.

Move 1 step at a time. Make notes of engine temperature and idle speed after every change. Keep focused and don't jump back and forth. Just do the basics and you will soon have that problem whooped! The Ford EECIV computer is fairly simple and with a few basic checks it is easy to trouble shoot.

Keep us informed and if you have more questions just ask away. We are still here although the Forum may be slow we hear your call.

Good Luck
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