Idle air control HELP

[Dexterb]

Hello all, yesterday I attempted to clean my idle air control valve and replaced the throttle position sensor on my 1997 explorer 4.0 ohv, I also sprayed out several electrical connections(got the idea from the “even the smallest gremlins post”)with compressed air.

Before the cleaning I was idling around 1100 rpms, afterwards the engine will barely run at all I have to give it gas to even crank. It now idles at around 300 rpms and sounds like it will cut off at any time, I’m lost on what to do next.

could cleaning the iac have made it worse? Is there a way to adjust the idle? if I rev the engine and let off the pedal quickly the engine dies completely.Thanks for the help guys!!!!

 

[410Fortune]

did you mount it upside down?
Not kidding

Did you clean the IAC valve or the valve and motor, because the motor side should not get "wet"
How were the O rings underneath the IAC?

 

[Dexterb]

did you mount it upside down?
Not kidding

Did you clean the IAC valve or the valve and motor, because the motor side should not get "wet"
How were the O rings underneath the IAC?

I certainly did wet the motor with carb cleaner, I honestly jumped straight into cleaning before researching. Would carb cleaner burn up the motor? The o rings look fine I definitely mounted it correctly, the wiring harness wouldn’t reach to the other side if mounted upside down. I know it was foolish of me to start cleaning without knowing what the hell im doing. OH BOY ocd strikes again

 

[Dexterb]

I certainly did wet the motor with carb cleaner, I honestly jumped straight into cleaning before researching. Would carb cleaner burn up the motor? The o rings look fine I definitely mounted it correctly, the wiring harness wouldn’t reach to the other side if mounted upside down. I know it was foolish of me to start cleaning without knowing what the hell im doing. OH BOY ocd strikes again

Is that a sensor with the red plastic on it? I had that come completely apart on me yesterday, I’m hoping I reassembled it correctly

 

[EB4X]

Hello all, y

Maybe you inadvertently cracked / loosened a vacuum line there while doing all that... do you hear any hissing while it's still running ?
And give your IAC a light tap with a hammer....maybe some crud got lodged down inside cleaning it......irony ...yes.....

 

[J_C]

Definitely check for loose or cracked vac lines, but I would also hook up a scan tool and see if any codes are set.

Yes that's a sensor connector and should be keyed to only plug in one way. Spraying the outside of the IAC motor (solenoid) with carb cleaner should not harm the motor but the cleaning in general might pull what little oil is left out of the bushing. That factor, along with this happening after removing it, would make me remove the IAC again, turn the IAC upside down (propped up on end) and put a drop of light oil on the shaft where it goes into the bushing and let that sit for an hour to soak down into it from gravity, and reinstall. This is more about just taking it off and putting back on than adding the oil, in case it somehow didn't seat right, but might as well lube the bushing while it's off.

Despite there being a silicone gasket on the IAC, they do make paper gaskets. If all else fails then I would throw a paper gasket on. If you don't have gasket material and just want to do a test, you could cut one yourself out of thin walled cardboard, like from a cereal box as a test, then if that works get a ready made gasket or proper gasket material to cut out a permanent one.

If you could get it running more consistently then with it installed you could try spraying carb cleaner around the IAC gasket area to see if it makes an RPM difference, suggesting there is a leak, or running you can look at scan tool live data for long term fuel trims to find a vac leak.

If your IAC has a vent on the side with a plastic cap on it, and you haven't yet, take that cap off, spray carb cleaner through that vent hole and also pull and rinse soot off the felt filter pads in the cap.

 

[Dexterb]

@Dexterb
Your profile is not specific; pic above seems to show a V6~4.0L~OHV engine, not the later SOHC?
A pic of the IACValve would also be helpful; it should have a Ford\MotorCraft part number stamp; there are several variations.
These are known failure items, so a new IACV may be needed, even after cleaning+lube & new Gasket\Seal\ORing.

You can adjust the IACV to minimize ColdStart RPM Flare, but I don't recommend it until you've got other gremlins resolved.
Details of the IACV adjustment process on my 2001 V6~4.0L~SOHC.

Engine AirIntake IdleAutoControlValve

2001~2005 ModelYear ExST V6~4.0L~SOHC engines were equipped with the IdleAutoControlValve\IACV shown below; it's in easy view+reach behind the ThrottleBody on the ManifoldThroat. The PCM computer controls StartingRPM\Flare using this Valve, depending on SetScrew position, & targets specific...

2001fordexplorersporttrac.fandom.com

Sounds like you've got more than one problem; start with pulling the OBD2 trouble codes.

Yes it is the ohv engine, it was running fine until I cleaned the iac, I have removed, cleaned, oiled, and reinstalled a good 10 times. I’ve cleaned the throttle body also and checked for vacuum leaks all over and can not locate any.

 

[Dexterb]

Maybe you inadvertently cracked / loosened a vacuum line there while doing all that... do you hear any hissing while it's still running ?
And give your IAC a light tap with a hammer....maybe some crud got lodged down inside cleaning it......irony ...yes.....

Yes I Hear some sort of hissing while I’m reving the engine but I can’t locate any vacuum leaks I’ve sprayed the lines with carb cleaner and it doesn’t rev up any at all. I’ve cleaned the iac a good 10 times and cleaned the throttle body. It was running pretty decent before I attempted to be a mechanic

 

[Dexterb]

Definitely check for loose or cracked vac lines, but I would also hook up a scan tool and see if any codes are set.

Yes that's a sensor connector and should be keyed to only plug in one way. Spraying the outside of the IAC motor (solenoid) with carb cleaner should not harm the motor but the cleaning in general might pull what little oil is left out of the bushing. That factor, along with this happening after removing it, would make me remove the IAC again, turn the IAC upside down (propped up on end) and put a drop of light oil on the shaft where it goes into the bushing and let that sit for an hour to soak down into it from gravity, and reinstall. This is more about just taking it off and putting back on than adding the oil, in case it somehow didn't seat right, but might as well lube the bushing while it's off.

Despite there being a silicone gasket on the IAC, they do make paper gaskets. If all else fails then I would throw a paper gasket on. If you don't have gasket material and just want to do a test, you could cut one yourself out of thin walled cardboard, like from a cereal box as a test, then if that works get a ready made gasket or proper gasket material to cut out a permanent one.

If you could get it running more consistently then with it installed you could try spraying carb cleaner around the IAC gasket area to see if it makes an RPM difference, suggesting there is a leak, or running you can look at scan tool live data for long term fuel trims to find a vac leak.

If your IAC has a vent on the side with a plastic cap on it, and you haven't yet, take that cap off, spray carb cleaner through that vent hole and also pull and rinse soot off the felt filter pads in the cap.

Thanks for the help, I’ve cleaned the iac multiple times and also lubricated it and it still hasn’t made a difference, it’s really strange because it was running decent before I cleaned anything. That sensor connector was actually in pieces also, I had to put it back together. Is that anything that could affect idle?

 

[J_C]

Most sensor values don't matter from a cold start in open loop mode.

Another way to look for vac leak problems is to systematically look at the furthest vac line on the intake, and then each closer and closer to the manifold and on it, pulling each (or pinching them if it were a newer vehicle where that didn't risk damage) and plugging the port hole so there can be no leak there, to see if that helps.

If you can keep it running long enough to do so, I'd still try to hook up a scan tool and look for the long term fuel trims to indicate a lean running condition from a vac leak.

Regardless, you stated the IAC gasket looks good, but I would want to make sure that it isn't leaking, hence the prior suggestion about throwing a makeshift cardboard gasket on to see if that makes any difference. It's FREE to try.

 

[Dexterb]

Most sensor values don't matter from a cold start in open loop mode.

Another way to look for vac leak problems is to systematically look at the furthest vac line on the intake, and then each closer and closer to the manifold and on it, pulling each (or pinching them if it were a newer vehicle where that didn't risk damage) and plugging the port hole so there can be no leak there, to see if that helps.

If you can keep it running long enough to do so, I'd still try to hook up a scan tool and look for the long term fuel trims to indicate a lean running condition from a vac leak.

Regardless, you stated the IAC gasket looks good, but I would want to make sure that it isn't leaking, hence the prior suggestion about throwing a makeshift cardboard gasket on to see if that makes any difference. It's FREE to try.

I’ll definitely give the gasket a try. What makes me nervous it that I did so many things at once that it might take awhile to figure out what’s wrong. I did all of the recommended cleaning of the pcm and the other connector that controls the o2 and transmission in the 2nd gen issues post, I swapped out the tps, cleaned the throttle body and cleaned the iac, and put in some fuel injector cleaner. Then it would not start anymore unless I give it a little gas, the idle is really low unless I press the pedal slightly. I purchased the explorer A few days ago and it had sit for a year at least prior to me buying it

 

[EB4X]

cleaned the throttle body and

Rule the following out: Take off your air-intake hose/tube at throttle body and carefully check the end of it....make sure the end is not brittle and crumbling.....I had this scenario on Ranger where due to age it was deteriorating underneath hose clamp (couldn't see) thus causing issue due to unmetered air sneaking in there after MAF and other tube sensor -- causing struggling idle-- with hissing sound too!
This could have happened when you took off / put back on after cleaning throttle body - long shot but rule it out.

 

[EB4X]

 

[Jim Eshelman]

Hello all, yesterday I attempted to clean my idle air control valve and replaced the throttle position sensor on my 1997 explorer 4.0 ohv, I also sprayed out several electrical connections(got the idea from the “even the smallest gremlins post”)with compressed air.

Before the cleaning I was idling around 1100 rpms, afterwards the engine will barely run at all I have to give it gas to even crank. It now idles at around 300 rpms and sounds like it will cut off at any time, I’m lost on what to do next.

could cleaning the iac have made it worse? Is there a way to adjust the idle? if I rev the engine and let off the pedal quickly the engine dies completely.Thanks for the help guys!!!!

 

[239]

Thanks for the help, I’ve cleaned the iac multiple times and also lubricated it and it still hasn’t made a difference, it’s really strange because it was running decent before I cleaned anything. That sensor connector was actually in pieces also, I had to put it back together. Is that anything that could affect idle?

I’ve never added any sort of lubricant to the IAC valve on my 2000 OHV after cleaning. I just spray it with electrical cleaner and let it dry before reinstalling.

Does your IAC valve have the tube on it with the sponge filter material at the end? It could be that’s blocked and needs to be cleared out.

 

[Jim Eshelman]

Replace the iac valve

 

[Hank102938]

Replace the iac valve

I second that and I’d recommend finding a Motorcraft one vs parts store brand. Replaced the iac on my 3rd gen with a non-motorcraft and ended up having issues with the idle surging as the trans downshifts causing lurching while coming to a stop. A improperly operating iac can cause sketchy behavior like that.

If you’re able you might want to verify the operation of the TPS first via scan tool or directly reading its resistance (not sure on the acceptable values).

 

[J_C]

I’ve never added any sort of lubricant to the IAC valve on my 2000 OHV after cleaning. I just spray it with electrical cleaner and let it dry before reinstalling.

Does your IAC valve have the tube on it with the sponge filter material at the end? It could be that’s blocked and needs to be cleared out.

Yes many people don't lube it, but it looks like a sintered bronze bushing which through time, heat, and especially after flushing the IAC out with cleaner, should benefit from adding back the light oil that it had when new.

When I first had IAC problems, maybe 14 years ago, I bought a new Motorcraft IAC because I wanted it fixed ASAP, was my daily driver at the time. Then I cleaned the old one and lubed it, swapped it back on just to see if that worked and it did, but put the new one back on anyway since I'd already bought it. A few years ago that replacement was gummed up so I swapped the original back on and cleaned the replacement so it's sitting in a box ready to swap in again.

Definitely get the Motorcraft, generic Chinese electromechanical mechanisms tend to be a crapshoot.

 

[McFudden]

Hello all, yesterday I attempted to clean my idle air control valve and replaced the throttle position sensor on my 1997 explorer 4.0 ohv, I also sprayed out several electrical connections(got the idea from the “even the smallest gremlins post”)with compressed air.

Before the cleaning I was idling around 1100 rpms, afterwards the engine will barely run at all I have to give it gas to even crank. It now idles at around 300 rpms and sounds like it will cut off at any time, I’m lost on what to do next.

could cleaning the iac have made it worse? Is there a way to adjust the idle? if I rev the engine and let off the pedal quickly the engine dies completely.Thanks for the help guys!!!!

Replace your IAC. They aren’t that expensive and cleaning them seldom works.

 

[drakon543]

skimming down through this post you mentioned you cleaned the electronics with carb cleaner. carb cleaner isnt a good cleaner to use on electronics as its very aggressive. its possible to damage electronics using it. its not a guarantee you will damage electronics with it but its definitely a potential concern. maf cleaner or electronics safe cleaner should be used only for sensors and electronic valves.