Idle Air Control (IAC) testing

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

well here is the good news and the bad news. The good news is my local toyota dealer worked hard at locating the two plug ends and the wires. The good news is also that i ordered both plugs so i can replace them with new waterproof ones. The bad news is that Toyota wants $28/wire! That's right, per wire! So to replace the four wire ends of the above shown TPS (Throttle Position Sensor) would cost $112 just for the four wire ends with the little rubber grommet and tips. That's just crazy!! So i'm going to see if i can rig up these olds ends on a new piece of wire before i spend almost $200 just for the wire.
 
Go with a patch job. Worst that could happen is you end up having to buy those #*&%@! expensive wires.

I'd be looking for a good used example of that thing in the meantime, even if the patch is 100%.

Does look like you've found the problem. Those wires were just waiting for you to jiggle 'em before FAIL.
 
I recently replaced my entire wiring harness. My rig has 250K and the wiring was like dried spaghetti. Anytime I got water in the engine compartment I had issues. The new plugs appear to be much more water resistant.
 
Hard to believe this little wire is $28!


I can't seem to get the ends to unfasten from the wire. I have some wire I can use but damn. :)

image-1356441414.webp
 
CJ, I think you're into something as mine has done the same for ages as well. The tuners suspect it might be the aftermarket fuel pump needing a non return valve installed, but I disagree as it seems to be temperature related - meaning that on warm days when I first start it, it's easy to catch and keep running by blipping the throttle slightly for 30sec or just holding it about 1200rpm or so at start up. Like yours, it idles perfect after that. But on really cold mornings, it can take several goes before I can catch it and keep it running. Once it has been started, it will start without issue all day. It's just when left over night that it becomes an issue when first started for the day.

My plug has also seen better days, as has the plug on top of the dizzy. I've purchased a 2nd hand plug for each from the wreckers (in perfect condition) for $35ea but am yet to install them. They just cut them off a spare harness. I note the ISCV has a small amount of adjustment but there's nothing in the FSM to indicate how to adjust it. I'll be following this to see how you fair. Good luck.
 
That's interesting! I will say that in hind-sight i should have got a new wiring loom when i did the rebuild. The wires are just baked to a crisp and that's something that is going to happen over time.

The odd thing to me is that i did not make any adjustments or changes on the throttle body. All i did was move it over a foot or so, so i am not wanting to open it up and mess with it at all. I want to assume it's just fine. Hopefully it's just a wiring issue.

Another note is that i started the truck yesterday with the TPS plug off. It started just like it had all the other times (needing to put my foot on the gas) but it threw a CEL code.
 
concretejungle said:
looks like tyco sales these things. Here is an online catalog.

http://www.connectorpeople.com/library/sealed_connectors/Tyco_AMP_Sealed_Connectors_65481.pdf
Click to expand...

Negative. Toyota does not use Tyco AMP connectors.

But in another thread, I think it was about seat heater switches, someone posted a link to Yazaki type 2.3II connectors and said that's what Toyota uses. I bookmarked the vendor...

http://www.newunitedracetech.com/shop/

...but haven't bought any of their connectors yet and so cannot verify they are an exact match for Toyota OEM.
 
I have the plug end with one of the wires pulled out in my hand and it says AMP stamped on the connector.
 
Did you inquire if CDan may have had a solution rather that buying each individual wire? I know I had an instance where I ruined the plug portion on my #1 Knock sensor and Dan had a pigtail from a different application that I CEL free. I realize this is a different situation than a one-wire plug, but it may be worth a shot.
 
94SRUNNER said:
Did you inquire if CDan may have had a solution rather that buying each individual wire? I know I had an instance where I ruined the plug portion on my #1 Knock sensor and Dan had a pigtail from a different application that I CEL free. I realize this is a different situation than a one-wire plug, but it may be worth a shot.
Click to expand...

I havent checked with him yet since i found out on Saturday afternoon about the wires and figured he didn't work on Sunday. So i'll give him a ring sometime today and ask. I kind of have a hunch that the $28/wire is really $28 for the four wire set. I know this same dealer once tried to sell me the entire rear lower control arm when i asked to buy the bushings. They said you had to buy the arm to get the bushings.... :rolleyes:

The link provided above has a wire end that appears to be the same as what is currently on the wire. I am going to measure again this evening and find out.
 
I got the plugs in today. Now i'm just waiting on the wire ends and i should be good to go.

This time i have purchased some more wire of the same gauge and plan on making just one connection, soldered.

IMG_2516.webp


IMG_2517.webp
 
Finally got the ends in. I decided to put new wire in place of the old wire, as much as I could. The original wire is cooked and brittle.

So, put the new ends on, which wasn't really a big deal at all. Then, clipped them into the new plug ends. I found out that even the smallest amount of solder on the metal wire terminal would keep it from fitting into the plug. I also tugged a little on the end to see if i could pull it loose and couldn't. I am figuring that the crimping mechanism is pretty darn tight and solder really isn't needed. The stock one's didn't have solder.

Plugged all the wires in and then clipped the yellow locking mechanism in place. So far so good..

I did not order the little rubber waterproof plugs that go into the wire holes where they enter the rear of the plug. So, i used some liquid electrical tape to plug the holes.

Then, i removed the tape and sleeve protection stuff that i had around my last wire job. As i was removing the casing, one of the wires was pulled apart at the faulty butt crimp from the last wiring (unfortunately like an idiot i do not remember if it was the IAC plug wire or the TPS plug wire). I am ASSuming that was the issue since now it works perfect.

Buttoned all the new wires up, plugged it in and it works fine now. :cheers:

IMG_2542.webp


IMG_2543.webp


IMG_2544.webp
 
You must log in or register to reply here.

Share this page

Back
Top Bottom