Idle Air Control? Or Something Else? | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Idle Air Control? Or Something Else?

rankins66

Member
Joined
November 6, 2011
Messages
15
Reaction score
0
City, State
Bucyrus, Ohio
Year, Model & Trim Level
2003 Ford Explorer 4X4
I have a 2003 4.6 V8 Explorer and a couple of months ago it started idling to slow and stalling. I bought a Borg Warner Idle Air Control from O Reilly's. After swapping it out it caused the engine to idle way up (around 2,800 rpm) at start up and it would slowly idle down to around 800 rpm. It would also idle up (around 1,200 rpm) when coming to a stop. Then it would drop to 800 rpm. It would even idle around 1,400 rpm while driving thru town causing me to ride the brake. I swapped out the Borg Warner IAC for a Standard Motor Products IAC with no change. I have checked for vacuum leaks. Replaced 1 cracked hose. No change. Throttle plate, Mass Air Sensor, etc. have been thoroughly cleaned. There are no codes coming up. The check engine light is off. I had the battery unhooked for at least 30 minutes when swapping out both IAC's. I also changed the Throttle Position Sensor for a Motorcraft sensor. No change. A local reputable mechanic hooked up his Snap On scanner to it and found nothing out of the ordinary. I have 12.5 volts at the IAC connector on the power side and the white/blue wire going to the PCM connector on the firewall shows almost no resistance. .1 Ohms. Last night I did another resistance check on the white/blue wire. With the key on and the engine off I had .8 Ohms of resistance. When I started the engine it idled up to 2,800 rpm and the resistance went to .380K Ohms. Then when the idle dropped down to normal the resistance went to .256K Ohms. Should I try a Motorcraft IAC from Ford or am I chasing the wrong thing? I'm at a loss. Thanks in advance for your help.
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





I would check/clean the MAF sensor and throttle body. Also, a can of Techron or Seafoam can sometimes go a long way.
 






It sounds like it could be the MAF. The IACV wouldn't cause that many problems I don't think. It also could be the ECU. You reset it, I know but this sounds like a perfect example of the ECU searching for the right fuel to air ratio. Keep looking for vacuum leaks as it would cause this.
 






I have cleaned the MAF sensor and the throttle body. Everything is clean. One other thing I did was remove the IAC and cover the hole with duct tape then cut a small hole in the duct tape to get the engine to idle at around 800 rpm. After I did this, I could turn offf the engine and reatart it and the rpm's would go up to about 1,500 rpm then immediately drop back down to 800 rpm. Before, with the IAC in place on a restart, the rpm's would jump up to about 2,800 rpm and hang there then slowly drop to 800 rpm.
 






IACs have a thin gasket - do you have one installed?
 












Did you reset the ECU? Look for vacuum leaks.:eek:
 












verify that the wires from the PCU to the IAC are intact, that deffinately sounds like an electrical fault if the problem was solved by removing the IAC entirely. Otherwise get it reflashed at the dealership, the PCU could be dieing.. but i think a frayed wire is far more likely.
 






If I have time tonight I'll run a wire from the PCU connection on the firewall directly to the IAC and see what happens. Bypassing the white/blue wire in the harness. I already did a resistance check on the white/blue wire and it showed no resistance but who knows. Thanks for everyone's help so far.
 






I bypassed the white wire with the blue stripe tonight. No change.
 






I had a lot of issues like you with fluctuating rpm's. I bought a standard iac, worked for about a week then started acting up again. I changed it out with another Standard IAC thinking it was a faulty unit with no change. I finally broke down and bought a Motorcraft IAC and have had no problems since. A buddy of mine is a Manager at a Ford Dealership and has told me that some aftermarket stuff is really good but when it comes to anything electrical gotta go OEM, said the PCM can't always recognise aftermarket products. Hope this helps. Good Luck
 






I installed a Motorcraft IAC last night and during a short test drive the Explorer seems to be doing just fine. I'll know more after today.
 






After driving several miles yesterday the Explorer seems to be running just fine with the Motorcraft IAC.
 






Good deal.
 






Back
Top