1989 Isuzu Trooper Idle Air Control Valve Replacement - High Mileage Repair

In this video, I diagnose my failing idle air control valve, show you a potential way to fix it, and then replace it. This is a common issue with the first gen Isuzu Troopers, but can also apply to other vehicles.
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[@urbanverificationist]

Just put a spanking new IAC valve in my 1990 Isuzu Trooper.. A few weeks ago, I replaced the ERG valve and solenoid and cleaned the EGR Port. Had to remove the intake manifold for that job.. So much fun. But hey, my Trooper idles fine and no longer stalls at stop signs.

[@HighMileageReviews]

Oh man, yeah that's a load of fun haha I've taken the intake manifold off a few times now and it never gets better. Everything is easy up until getting the egr pipe on and off

[@DanielSilva-uj3sj]

Cool! I think I’m looking at the same problem. Currently replacing vacuum lines. Of those still present, some don’t match the diagrams. Regardless of the problems finding parts, I want to keep this cool little project vehicle. Not many like it in the Tucson area.

[@HighMileageReviews]

Good luck! Those vacuum lines can be very confusing

[@tommeyer6875]

Hey out there in isuzu land, I have a 1988 trooper and am in need a an IACV, I've been scouring the internet with no luck. Any suggestions or does someone out there have a spare? (Tom in Colorado)

[@philgriswold2133]

I have that exact problem on my 1989 2.6 Trooper. I really excited now.

[@HighMileageReviews]

I hope you're able to maintain that excitement as you struggle to loosen the two small bolts! Best of luck

[@philgriswold2133]

@@HighMileageReviews I let you know how it goes. I tried the PB Blaster method tonight.

[@hahajoel]

I feel you. I replaced my IAC valve and went through the same frustration of removing the 2 bolts that secure it. When I reinstalled it, I picked up 2 longer bolts with locking washers and nuts and flipped them around so they would be easier to reinstall and uninstall if i ever needed to. Looking back on the issue of why I changed my IAC valve, I don’t think I actually needed to do it haha

[@HighMileageReviews]

I considered doing the same thing by getting longer bolts, but there's very few metric options at my local hardware stores, and I didn't feel like waiting to have some shipped to me. I just hope I don't have to do it again

[@hahajoel]

@@HighMileageReviews I wasn’t able to find anything that threaded correctly either so I just got bolts that were slightly smaller in diameter so it fit through then secured it with a locking washer and bolt. I also hope to never do it again 😂

[@RooflessVW]

@@HighMileageReviews I just relocated mine instead of putting it back

[@OttoTime]

I drilled through the threads, put bolts through the holes and nuts on the inside. Now it's not hard to get a socket wrench on the bolt heads, more room to ratchet while I hold the nuts steady.

[@meatsmell8639]

What wheels/tires do you run? I'm looking to fully re-do my 1990 Trooper and I love the look of your setup!

[@HighMileageReviews]

They're Mickey Thompson Baja MTZ P3 tires, size 31x10.5x15 on the factory optioned "snowflake" style wheels

[@mrpotato85]

If the valve is shut closed while cold and on the bench, loosen the sealed screw on the bottom. The screw is connected to the inner spring plate and can move a whisper. Move it all the way and tighten it back down in place. The plate and opening should be in the proper cold starting position at this point. Put 12v to the two terminals and the plate should close in 2-3 minutes (high starting idle-warm idle). Disconnect power and it should return to the open position as it cools back down. Test it a few times to be sure.

[@mrpotato85]

And nice trooper btw 👍 The “5tec” mod is really worth doing to clean up the itec if you can get away w it. I know in Cali those kind of alterations are a no no.

[@HighMileageReviews]

Good tip! I probably should have tried testing the valve in the bench like that before getting a new one...next time I guess. I've considered the 5tec mod, but it's running well these days, so I'll tackle that if I get desperate haha

[@sjanbob]

But still you need to remove the valve from the engine for to turn the screw right? My engine is idling fast when it's cold and when engine is warm he will shut off like the video or suddenly he will run fast again. Do I have another problem?

[@mrpotato85]

Yes you must remove the valve to get at the screw easily. Also you want to be able to watch what the internal plate is doing under 12v load. Not sure what your issue is exactly but w a properly working valve the idle will start high and then gradually settle down upon warmup. Idle should be around 1000rpm once warmed up. If you still have a stock thermal vacuum valve on top of the thermostat housing I've read that that could contribute to high/surging idle due to trapped air in the cooling system. Maybe you've found the issue by now? @@sjanbob

[@northvankiwi]

did you ever find the problem@@sjanbob? my 4ze1 has a similar problem. good idle cold, bumpy idle while warm

[@jamesamurdock93]

I really appreciate you man! Got a 1989 Isuzu trooper as well. Really been idling weird while stopped, is that a sign of mine going bad?

[@HighMileageReviews]

Possibly. Typically though, if the iacv is bad, the idle issues are only apparent when the vehicle is cold. Once it warms up, the car should idle well. These troopers are notoriously difficult to get a perfect idle, so your issue could be any number of things. mainly, check all your vacuum lines. Cracked or loose vacuum lines are probably the biggest culprit for a weird idle. Then check your timing, get that in spec. Then adjust your idle speed once you know those first two areas are perfect. Your idle should be much improved if you check all that. For safe measure though, you can spray pb blaster down the tube leading to the iacv and let it soak overnight like I did, and see if anything improves. That's the easiest thing to do and can only help keep the iacv in good condition of anything.

[@jamesamurdock93]

@@HighMileageReviews I thank you so much man! Speedy reply + very helpful. You gained yourself a follower in me. What website do you use to find yourself these Isuzu 89 trooper parts??

[@HighMileageReviews]

@@jamesamurdock93planetisuzoo.com forum members Shawn Anthony and Jerry Lemond are good resources of hard to find trooper parts. Though more common items can still readily be found on rockauto or at your local parts store

[@SarahSaintLaurent-y3g]

Having the same problem with the idle raving up and down. I sprayed pb down the line like you did and now the truck won’t start at all. Did I clog something doing that?

[@HighMileageReviews]

Unlikely. Unless you dumped a whole bottle down there

[@MrBowNaxe]

Where did you find the IAC valve? I'm looking for one to see if that's the issue on my '91. My Trooper "surges" at idle and won't idle below 1200 rpm. Thanks for sharing.

[@HighMileageReviews]

There's a user by the name of Shawn Anthony on planet isuzoo. He has an inventory of trooper parts. That's where I got mine

[@MrBowNaxe]

@@HighMileageReviews was it used? Trying to decide if I get one or to pull mine and overhaul it.

[@HighMileageReviews]

@@MrBowNaxe it was a used part, in verified working condition

[@getsducks727]

I see he is now banned on the Planet?? What did you pay for yours? Thanks@@HighMileageReviews

[@jorgedanielmartirena9514]

genial amigo! donde puedo conseguir el repuesto? isuzu genuines parts?

[@HighMileageReviews]

Rockauto.com

[@ethangrover5382]

Hey man I love the trooper, I really need an aftermarket rear bumper, do you know of any? Otherwise I will have to resort to building one myself.

[@HighMileageReviews]

I'm not aware of any. The bumper on mine was fabricated by one of its previous owners

[@charlesm7677]

I love these troopers

[@HighMileageReviews]

Me too!

[@cjscars]

Where did you get your lift kit? Also what wheels and tires are you running?

[@HighMileageReviews]

No idea about the lift kit. It was on the truck when I bought it. For tire information, see my video review that I made

[@SeraphinaBurningOne]

Is that iac you replaced in the video for a 2.6L? I’m having some weird idle issues with high rpm levels. Was told it’s the iac. Yet I cannot find it anywhere!

[@HighMileageReviews]

Yes, 2.6

[@DeafWhatYouHerd]

There is a metal clip on the plug similar to the one on the mass air flow sensor

[@HighMileageReviews]

Yes there is

[@joshuathompson2131]

Did you have any other idling issues? I have one that keeps reving so I think vacuum leak but would the idle air control valve be part of that issue?

[@HighMileageReviews]

That was my only idle issue, but yours does not seem related to the idle air control valve. Vacuum leak seems likely, however

[@joshuathompson2131]

@@HighMileageReviews you should drive down to Benson AZ and help me out 😉

[@zacheryashworth7255]

Does it idle high and after about a mi ute or so just Rev up and down in 1-2 second intervals? I'm having this issue and can't find a fix

[@adurpa4843]

It's about time

[@HighMileageReviews]

It's about time for what?

[@sterlingarcher813]

@@HighMileageReviews deez nuts

[@HighMileageReviews]

@@sterlingarcher813 uh huh

[@cjscars]

Also, where did you get your front end replacement?

[@HighMileageReviews]

Came on the truck when I bought it

[@GwynAndJulius]

Where did you get your iac from? I can’t find any online at all thanks

[@HighMileageReviews]

A man by the name of shawn Anthony in the planet isuzoo forum

[@GwynAndJulius]

@@HighMileageReviews do you mind messaging him for me? It seems as I am not able to message on the site

[@HighMileageReviews]

@@GwynAndJulius sorry, I can't do that for you. If you have an account on the forum and for whatever reason you can't message someone directly, you can comment on his post in the classifieds/for sale section and he will likely respond to you

[@GwynAndJulius]

@@HighMileageReviews thank you

[@jaysmith6255]

my 88 trooper quit while hot and now starts but only runs a few seconds. could it still be valve?

[@HighMileageReviews]

That might be something different. From my understanding, a stuck valve usually only affects cold idle

[@keiths2027]

Did you get this fixed? Jonny5 has a video about the fuel relay/pump bypass. Works great in a pinch and for years if you forget to get a new relay...

[@frederickroland8278]

Hola buenas tardes, tengo una rodeo 2.6 que huele a gasolina en el exosto, y algunas veces falla como si faltará chispa en un cilindro

[@HighMileageReviews]

Interesting. I have not had that issue. Good luck!

[@dwightvaldez311]

How do you take it out of four wheel drive

[@HighMileageReviews]

With the stick coming out of the floor

[@skcdav410]

I have this exact same problem in my 88 Trooper, it has the 2.6 engine, so I believe I found where I'm going to kill about 4 hours of my life next weekend lol

[@HighMileageReviews]

Good luck!

[@elijahdanner4056]

Where can I find an IAC? They seem to be discontinued. I know I can find one though. Please help. Lol

[@HighMileageReviews]

I got mine on the forums. A couple people might have them. I got mine from a user named Shawn Anthony. He has a business and will sell you new or refurbished parts for your trooper. Also Jerry Lemond can get new parts from Japan I believe

[@elijahdanner4056]

Thank You! I’m looking into it now. Appreciate you and your videos

[@joshuatheagene3409]

@@HighMileageReviews could you possibly leave a link Unable to locate one. Also suspension options have you been able to locate anything?

[@HighMileageReviews]

@@joshuatheagene3409 planetisuzoo.com is the place to be. I haven't had to shop for suspension parts yet, but the forum should offer some options, and I'm not sure what RockAuto has, but I usually check there first

[@MrBowNaxe]

You described that procedure exactly! I'm trying to get my Dad's '91 running. Fuel pump was the main issue but the idle is killing me... I'm fearing the dreaded IAC replacement (if I can find one). Thanks for sharing.

[@KABOBkabob]

This looks like a ratcheting wrench type of situation

[@HighMileageReviews]

Yes that would definitely have helped

[@johnnyarnett4904]

I got a 1994 isuzu 2.6 spacecab doing same thing

[@HighMileageReviews]

Good luck! Have patience!

[@johnnyarnett4904]

@@HighMileageReviews u mean sell it lol

[@johnnyarnett4904]

I would love to keep it I have had the truck 6 years and I love it. But hate working on it ..I got a guy comming this weekend to get it fir 2500.00 and I bet a 50 buck part will fix it and a case of beer lol

[@johnnyarnett4904]

@@HighMileageReviews well I got it off and it looks good ..I guess the blaster mite have freed it up..I'll put it back on monday and replace the rubber line going to it

[@Isuzu-Specialties]

This part does not function anything like an Idle air control valve. It is in-fact this part is not even called an IAC. There are 5 devices to control the idle on this engine this is only part of the system. The spraying oil down into the valve is a dumb idea. If the fault is not this part you have just destroyed it by doing so. First check for voltage at the valve is the proper way to troubleshoot. A 1/4:" drive swivel head long handle ratchet will get to the bolts with ease. The replacement of this part takes about 25 mints total. Most importantly this part is rebuildable. You don't need to buy used 30+ year old valve.

[@HighMileageReviews]

Ok, tell that to everyone on the forums

[@Isuzu-Specialties]

​@@HighMileageReviews@HighMileageReviews I have... You must have missed it You sound intelligent enough not to think for yourself and not think what you have been told. Perhaps I was wrong. PlanetIsuzu & other forums are sheep that can only follow the herd.

[@VictorIxchel]

Where are all of the idle mechanisms in this system, and how can they be tested?

[@Isuzu-Specialties]

​@@VictorIxchel thermal temp switch,AAV, FPR-SVS, AAV, A/C & Power steering load. There is no simple way to bypass.