Unplug Idle air control valve and engine dies (2.9L V6), Normal or bad valve?

[1986RangerXL]

What were your symptoms? Mine has an erratic idle (Normal, then drops off completely) until it's warm, at which point it idles like it should. And it misses under load.

Some days I want to leave this thing on the corner with a 'For Sale' sign.

 

[wildbill23c]

What were your symptoms? Mine has an erratic idle (Normal, then drops off completely) until it's warm, at which point it idles like it should. And it misses under load.

Some days I want to leave this thing on the corner with a 'For Sale' sign.

I was having some idle issues where it was surging up and down, the valve itself was stuck, even cleaning it didn't do anything, so I replaced it. Next issue then was while driving after the truck was warmed up it would start losing power, bucking, hesitation. I replaced the TPS thinking that may have caused it due to the erratic voltages I was getting from the TPS when testing it, still didn't correct the problem, although seemed to lessen it a little. Another forum member suggested a fuel pressure test, and at first I thought why, the fuel pump, fuel filter, fuel lines, fuel pressure regulator, etc. are all new...then I thought well heck I got the tester why not give it a go, at idle I was getting 28psi, slightly below the 30 or 32psi it should have, but upon revving the engine up a bit the pressure was dropping clear down to 10-15psi, which for fuel injection I figured was way too low even just revving the engine in the driveway not under load. So I unhooked the fuel pressure regulator vacuum line, fuel pressure immediately shot up to about 43psi which was good and stayed there even while revving the engine. I did take it out for a short drive without the regulator hooked up and it drove fine, which leads me to believe the new regulator isn't any good....I've gotta get a replacement ASAP then do more testing, but I am hoping it is just a fuel pressure issue.

 

[RonD]

Good testing

Yes, "new" used to mean "tested and working", it now means "YOU test it for us, and we will replace it under warranty if it doesn't work"

 

[cbxer55]

Just as a heads up, there have been quite a few issues with 3rd party IAC Valve, better to get Motorcraft even at a wrecking yard, the same model IAC Valves were used on many engines

Auto Zone has a premium part made by Hitachi in Japan. Much better than their made in Mejico part. My Ranger eats up the Mexican parts. but the Hitachi one has been on it since 2015, no problemo. I also installed one on my Lightning in 2017, to replace the made in Mejico part that was going south. The Mexican one costs like $39.99, the Hitachi 69.99. At least that's what the two I bought cost me.

You want to hear something freaky. I suppose it's due to the intake dynamics, the big plenum on top of the blower where the IAC is mounted on the Lightning. When the IAC goes bad, it really does sound like a moo cow. Idle surges up-and-down around 500 rpms, and the weird mooing cow sound. Loud too. Everyone is looking, like WTF is that? LOL!!

 

[RonD]

Yes, I have read Hitachi IAC Valves were OK to use with Ford systems

 

[cbxer55]

Not as far as I know.
Read RonDs post below my last post.

On mine, it does in fact raise the idle speed. But, there comes a point when you will get a default code for idle being too high. Been there done that.

 

[1986RangerXL]

Where'd you order your IAC? I see Motorcraft on Ebay, but not anywhere else

 

[wildbill23c]

Where'd you order your IAC? I see Motorcraft on Ebay, but not anywhere else

Rock Auto.

 

[1986RangerXL]

Rock Auto.

That's where I looked first, I see WVE, Standard Motor Products, and Hitachi

 

[wildbill23c]

That's where I looked first, I see WVE, Standard Motor Products, and Hitachi

I doubt you will find much in the way of OEM for it, mine seems to be working fine, and I got the cheapest one they had if I recall. Trouble with Rock Auto is their shipping can get a bit ridiculous. I've ordered a lot of stuff from Rock Auto and the Fuel Pressure Regulator I got from them a couple months ago is the first part I've got that wasn't any good. So I resorted to Ebay for another no-name brand which resulted in having an o-ring that wasn't any good, so I pulled the o-ring off the old one and put on the new one so far so good after thoroughly soaking 1/2 the engine bay in gas yesterday morning from the bad o-ring LOL. All these no-name parts that every parts house in the country is selling are pure junk, I may as well have taken a chance on a 30 year old used on from pick a part LOL...probably would have worked better....if I knew what size o-rings and where to get them I probably should order a few. I think it may have been sucking air through wherever it was leaking fuel at too which was probably part of the original issue.

I still get a bit of a power loss randomly, not nearly as bad as it was when I started chasing the problem though, and now I am seriously thinking and wondering if my ignition coil, alternator, or battery or all the above are on their way out. I swear its a random missfire, or lack of spark maybe? This morning I turned the heater on, and as soon as I did it started having an idle surging issue revved it up a couple times it started idling normal...then turned the head lights on, same issue...so I'm now thinking I've got an electrical power issue...but the battery is new, alternator sounds a bit noisy so I'm leaning towards an alternator that's failing, I get about 14V at the battery when its running, and 12.7V without the engine running....which I know means nothing for cranking amps, but if the alternator is starting to fail, I am guessing the sudden power draw from the blower motor and headlights would certainly cause the idle surging issue because of the sudden drop in voltage.....more testing needed, and back to work tomorrow so, it'll be next weekend before I get back to it. At least I'm starting to get things sorted out on it, slowly, probably replaced a couple parts that didn't need to be, but at least I know they're good now.

 

[1986RangerXL]

Yeah, all these no-name parts are terrible, and last I checked the junkyards around here don't keep trucks this old. Need a pick-n-pull here.. I will go with Standard Motor Products like PetroleumJunkie suggested.

Sounds like we're dealing with a lot of the same issues, hopefully it works out soon. If you do decide to replace the alternator, try to find a local shop that rebuilds them. It was a lot cheaper

 

[wildbill23c]

Yeah, all these no-name parts are terrible, and last I checked the junkyards around here don't keep trucks this old. Need a pick-n-pull here.. I will go with Standard Motor Products like PetroleumJunkie suggested.

Sounds like we're dealing with a lot of the same issues, hopefully it works out soon. If you do decide to replace the alternator, try to find a local shop that rebuilds them. It was a lot cheaper

Nothing around where I live that rebuilds alternators, or motors of any type anymore sadly. I ordered a 90amp alternator for my Bronco 2 on Ebay a couple years ago for a pretty reasonable price, so I'll probably just hit up Ebay, far better luck with Ebay and Rock Auto parts than anything from Autozone, Oreilly, NAPA, etc. I've actually had a higher success rate with parts like that from pick a part than remanufactured stuff from a part store LOL.

Drove the Ranger to work this morning, let it idle a couple minutes and drove away, while it was bucking, and didn't have any power....after work I started it and let it run for about 5 minutes before leaving and it was fine, so I'm wondering if I got a bad alternator not putting out enough juice to keep it running right once its got a load on it like headlights, blower motor, etc....gotta do some more checking.

 

[franklin2]

Stop guessing. If you think the alternator is bad, get a voltmeter and wire it in so you can glance at it in the cab while it throws a fit. Of course if the engine is not running well, the voltage will drop a little bit, so expect that.

No where in this thread did I see reading codes mentioned. I know these EECIV systems can be cantankerous sometimes and reading codes does not always lead to a solution, but sometimes they do help. I had a battle like you with random bucking and after reading the codes over several weeks a TPS code finally reared it's head, I replaced it, and all was mostly well. I still had a little buck in it once in awhile, especially when pulling the engine hard. That ended up being the pickup in the distributor, I got a code 18 in the memory codes.

Be warned if you want to change the module in the distributor, you have to pull the dist apart. But I would recommend doing that instead of getting a rebuilt dist. I bought the module and went to pull the gear off, and was not careful enough and broke some teeth. No one had a replacement gear. So I ended up buying a rebuilt dist from local parts store from Cardone. Installed it and it was worse than the one I took out. That gave me a clue I was on the right track. I took the Cardone dist back out, and was more careful this time and tore it down, they had not even taken it apart. It was full of old sticky carbon and black grease, the module was not even replaced. I cleaned it up, put my new module in that I had bought before, installed it and it ran great after that.

 

[wildbill23c]

Stop guessing. If you think the alternator is bad, get a voltmeter and wire it in so you can glance at it in the cab while it throws a fit. Of course if the engine is not running well, the voltage will drop a little bit, so expect that.

No where in this thread did I see reading codes mentioned. I know these EECIV systems can be cantankerous sometimes and reading codes does not always lead to a solution, but sometimes they do help. I had a battle like you with random bucking and after reading the codes over several weeks a TPS code finally reared it's head, I replaced it, and all was mostly well. I still had a little buck in it once in awhile, especially when pulling the engine hard. That ended up being the pickup in the distributor, I got a code 18 in the memory codes.

Be warned if you want to change the module in the distributor, you have to pull the dist apart. But I would recommend doing that instead of getting a rebuilt dist. I bought the module and went to pull the gear off, and was not careful enough and broke some teeth. No one had a replacement gear. So I ended up buying a rebuilt dist from local parts store from Cardone. Installed it and it was worse than the one I took out. That gave me a clue I was on the right track. I took the Cardone dist back out, and was more careful this time and tore it down, they had not even taken it apart. It was full of old sticky carbon and black grease, the module was not even replaced. I cleaned it up, put my new module in that I had bought before, installed it and it ran great after that.

Why do you think I haven't replaced anything yet. I'm not guessing I'm checking things over first.

The distributor is new, and the module on the distributor is held on with 2 bolts, you don't have to tear it apart to change it. The TFI is a separate part just so happens that Ford put it in the worst place possible. Too bad the EECIV system doesn't really lead you into any definite possibilities LOL, would be much more helpful. That's the first place I went was to pull codes and nothing. I haven't ruled out the distributor & TFI module both being bad even though they're both new though.

There are no codes, its a huge guessing game of what part to check and fiddle with first.

First thing is to stop the stupid fuel pressure regulator from leaking fuel out of the fuel rail/regulator area, apparently the brand new o-ring isn't any good or something that's where its leaking, and its fully seated.

Luckily this isn't a vehicle I need so I can just as easily send it to the scrap yard if I get fed up enough with it.

 

[wildbill23c]

A code check again this afternoon turned up just the standard 11 code. I figured there would be some codes in there for something since the dang thing was lacking power this afternoon on a test drive when I found the fuel pressure regulator was leaking once again. I swear this is the 2nd regulator and the same fuel leaking issue from around the o-ring, can't get the screws on it any tighter, so there's gotta be something not right with the o-rings, the new o-ring that was on the 2nd regulator was so bad it was spraying fuel all over the engine bay, the o-ring off the old regulator the leak is just a small seep, but enough to know its leaking and you can smell it.

I'll have to get my longer multimeter test leads so I can more accurately see what's going on with the charging system and battery. If either aren't up to snuff I'd think that could be causing the power loss issue and bucking since the voltage dropping low enough wouldn't allow the ignition coil enough voltage to properly fire the plugs I'd assume. Definitely more testing needed. May pull the battery out of my Bronco 2 which is known to be good which would allow me to rule out the battery as the cause. Why are weekends so far away when there's much better stuff to do like work on a 33 year old truck that the PO I assume didn't do too much in the way of maintenance LOL...at least they kept the oil/filter changed and the truck relatively clean.