I have a 94 Land Cruiser that will run good but as soon as it is at running temp the rpm will surge real low and jump back and forth. It just recently started getting low enough to where it just stalls/dies. I first thought it was the mass air meter so I put a reman in and tuned it a tad(it was a 93 camry reman, fits perfectly, was just to lean etc) but it is doing the same thing it was with the old meter,(with the addition of it stalling occasionally). I pulled the plug on the IAC and started it and the idle shot to 2k rpm and began surging from 1k rpm to 2k rpm. I plugged the IAC back in and it continued to surge for another minute and then went to a normal rpm(which allowed me to drive the rest of the way up my drive and to my parking spot.) I feel like I need to add that the reason I though the issue was the mass air meter was upon cold start up I had to press the gas multiple times before it started, and after puttong the reman on and adjusting it, it starts every time, the other issue just shows its face at operating temp.
94 LC Possible IAC issue(Idle air control valve)
- Thread starter JDennison
- Start date
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voodu3
SILVER Star
This might help with tracking down the issue.
Also Check the condition of the air intake tube they can get small cracks in them especially on the underside from years of heat That can cause the surging from unmetered air getting in. I would check the timing if you’ve had the distributor Cap off to replace the o-ring. Lastly check the accelerator cable. Adjusting it to get your idle set and that it moves freely.
Also Check the condition of the air intake tube they can get small cracks in them especially on the underside from years of heat That can cause the surging from unmetered air getting in. I would check the timing if you’ve had the distributor Cap off to replace the o-ring. Lastly check the accelerator cable. Adjusting it to get your idle set and that it moves freely.
With ISC disconnected it will go to 2000. After you have it running and you shut it off you should hear the IAC cycling, clicking like sound, this is normal. The IAC, after shut down, goes to full open. This causes leanness on start, wanted to increase start-up rpm. But it should not go to 2000, it should go to about 1200 rpm at first start, as the IAC starts closing when you start motoring to start. If there is a carbon build-up on throttle plate or IAC seat rpm will be higher at start.
There are checks in the FSM for it.
There are checks in the FSM for it.
Hey sorry to dredge this thread up but did you ever figure out what the cause was for your idle surge at running temp my 94 is doing the same thing and it's driving me nuts figuring it out?
I’ll throw in here as well. My truck starts right up, but idles at 1200-1400 rpm in park, and when I shift into gear, it’s at 1000. We are replacing vacuum hoses today. I can’t get the bolts to the IAC out without stripping. Have hit it half dozen times with blaster - using Japanese bits, etc. so frustrating!
I know it could be many things, but will new hoses and a cleaned up IAC likely return me to proper idle?
I am having a thorough inspection done next week at a specialty shop and am asking them to see if they can get bolts out and clean IAC while there.
I know it could be many things, but will new hoses and a cleaned up IAC likely return me to proper idle?
I am having a thorough inspection done next week at a specialty shop and am asking them to see if they can get bolts out and clean IAC while there.
Old Nick
GOLD Star
Good up advice up there ^
I went through idle problems on my wife's rig. It's sorted now. In our rig's case it was the IAC. The TPS had failed also.
This rig was extremely neglected when we bought it, so it needed all of the vacuum hoses replaced, and the intake (which was cracked underneath and not visible). The ports in the throttle body were clogged with carbon too. That got pulled and cleaned properly.
It's easy to pull the IAC and to test it. Just use the FSM. All of the how-to's are there.
As others noted, it's a good idea to check timing and throttle cable tension too.
Start at the air filter and work your way through the intake system up to and including the throttle body. Clean and replace things as necessary.
I went through idle problems on my wife's rig. It's sorted now. In our rig's case it was the IAC. The TPS had failed also.
This rig was extremely neglected when we bought it, so it needed all of the vacuum hoses replaced, and the intake (which was cracked underneath and not visible). The ports in the throttle body were clogged with carbon too. That got pulled and cleaned properly.
It's easy to pull the IAC and to test it. Just use the FSM. All of the how-to's are there.
As others noted, it's a good idea to check timing and throttle cable tension too.
Start at the air filter and work your way through the intake system up to and including the throttle body. Clean and replace things as necessary.
Old Nick
GOLD Star
Here is a good thread regarding IAC problems and solutions:
Do yourself a favour and remove anything that prohibits a straight on engagement with the IAC screws.
A extra long screwdriver works best
Yup did that. They are just really seized in there. I don’t have the means to get them out if I strip them so think I’ll let the shop do it, and they can get them out if stripped.
They are quite soft imop, and I think they are only m3 I believe, so ya, they suck!
Did you clean your TB yet?
I super cleaned mine and after that, and IAC cleaning and TPS rigging as per FSM she works beautifully.
Use to start and go to 16-1800 and like you settle off to 1000.
After cleaning it’s like 11-1200 on start and after a few drops to 800 and idles exactly at 650 when warm.
All vacuum hoses replaced with OEM and EGR and pair delete.
Fj80oregon
GOLD Star
With the right tools the only thing that needs removed is the spark plug front cover.
Plan to clean that as well. Thx. All my hoses are OEM as well.