4.0 wont idle..

[will2045]

I recently bought a 94 ext cab 4x4 4.0 5spd that had front end damage for 800. i put a front clip on it, dropped in a batt. bolted down some grounds that were undone bolted down the starter syln., hooked up the vaccum lines to the black box near the drivers side frame rail, dropped in a rad and hooked it up, put on the tube from the air box to the throttle body, and mounted a thing i dont knwo what it is. looks like a canister mounts on drivers side firewall has a cable running to the throttle body with a nipple on the front bottom that looks like its for a hose that i cant find prolly vaccum.

so the problem is it cranks a couple times then starts up but itll rev up to about 2000 after firing up then falls out and dies. i can feather it to keep it running but it doesnt run very good when i do that and i cant rev it above 2000. any ideas? it seems like im still missing something as far as putting it back together. any ideas would be awesome just throw stuff at me and ill try it all till i find it.

 

[BlackBII]

If it will stay running with your foot on the accelerator, but it dies when you let off, I would blame the IAC. Its the Idle Air Control valve, it's what controls the idle. Most likely it is dirty and not opening, so it wont idle. I would pull it and clean it out, making sure the plunger inside moves freely back and forth.

http://fordfuelinjection.com/?p=39

 

[will2045]

If it will stay running with your foot on the accelerator, but it dies when you let off, I would blame the IAC. Its the Idle Air Control valve, it's what controls the idle. Most likely it is dirty and not opening, so it wont idle. I would pull it and clean it out, making sure the plunger inside moves freely back and forth.

http://fordfuelinjection.com/?p=39

where is it located and whats it look like?

 

[BlackBII]

On the drivers side of the intake plenum. Two 10mm bolts holding it on, and one electrical connector

 

[grh777]

I'm having the exact same problem with my 92 Ranger. I recently installed an engine from a 94 explorer and it ran smooth as silk but had a small oil leak so I took it back apart and repaired the leak this week and now, reassembled, it revs up to 2000 rpm and dies. I've triple checked all connectors and vacuum lines and still can't figure it out. I've disassembled and reassembled this this engine so many times I thought I could do it with my eyes closed. I must be missing something.

Can an IAC go bad or get dirty just sitting there for two days?

 

[grh777]

Well I just found my idle problem. There's a wire bracket that fits on top of the first intake manifold bolt. I had this bracket underneath the manifold causing a vacuum leak. Runs good now after I put it where it goes. My goofy mistake.

I'm sure your leak is something simple to fix like mine. Good luck.

 

[will2045]

On the drivers side of the intake plenum. Two 10mm bolts holding it on, and one electrical connector

whats the best way to clean it?

 

[BlackBII]

Carb cleaner.

Spray some in there and let it soak a minute. Then try to move the plunger back and forth. Usually the plunger gets clogged up with carbon buildup and it doesn't slide like it should.

Here is a great page on the process

http://www.explorer4x4.com/iac.htm