88 Supra Idle Speed Motor - Toyota Nation Forum : Toyota Car and Truck Forums

ratnin57 · 09-21-2004, 12:38 PM

I have a 88 Supra non Turbo 7MGE. After washing engine it will not Idle below 3000 rpm. I ran tests on Idle Speed Control and it checked out according to book. I ended up taking to Toyota Dealer and after replacing some hoses and adjustments for $400 they say it also needs a Idle Air Control Motor for another $500.
I looked up parts on a Toyota dealer website. They list an ISC valve for $200 and a Idle Speed motor (Idle Air Control Motor ???) for $450. I am thinking about going used parts and would like to know where the Idle Speed Motor is located and is it a different part or just another name for the Idle Speed Control.

Kenny

Jeeves · 09-21-2004, 01:06 PM

DO NOT BUY MORE PARTS.

In 95% of Supras the ISC (Idle Speed Control) [It is also called the IAC Motor (Idle Air Control), they are the same part] does VERY little. I.e. in mine and my buddies you can flat out unplug it and it will not phase motor function at all.

In all likelyhood you got water where it's not supposed to be, in fact, it's a common belief that it's BADDDDDD to wash the Supra motors. There are several places where water can pool, and has been known to cause fires. It has also been known to foul up other sensors, and make the car run like absolute ass, which is what yours is doing.

1) How long has it been?
2) Did you cover any parts of the motor before you hosed it down?

In most cases it usually takes a good amount of "dry out time" then the vehicle runs fine.

ratnin57 · 09-21-2004, 02:26 PM

The car belongs to my friends son and he washed his engine Saturday a week ago. This is his first car and he sprayed the degreaser on the engine and then washed it down with high pressure sprayer at carwash without covering anything. Toyota replaced the large air intake hose between thottle body and air cleaner becaused it was repaired with duct tape and they said they could not properly diagnose without air leaks repaired. I noticed the ISC valve has a crack where you plug harness into it. I checked valve with ohmn meter and it was within specs. Valve clicks when key is turned off as it is supposed to. Im just trying to keep them from getting soaked by a mechanic that is guessing. I told her to pick up the car and have them show her what they did and what it needs.

Kenny

turbomic · 09-21-2004, 10:15 PM

in most cars, if you have access to a scan tool, not one of the cheap ones and you can see if the iac or ias is open or closed it is expessed in counts from 0 to 30 or 100 0 being closed 30 or 100 being open or the outher way around. don know if that will help

Jeeves · 09-22-2004, 02:03 AM

Turbomic, you are referencing OBDII, the mk3 supra is not equipped with OBDII and hence a scanner type device is not available to read said values.

turbomic · 09-22-2004, 07:55 PM

your right sorry
But if it is idleing a 3000 it is most likely stuck open. Most iacs get jammed with carbon build up from the pcv system going into the intake. If you have not tried this allready do it before you replace it trie wiggling the conector if this does not work take the intake hose off and look you will see a hole just before the throttle plate. Get a can of carb / choke cleaner and spray it down the hole it is best to spray a little at a time so you do not flood the motor I normally do this when it is running If you do it when it is of the car normally is a bitch to start. Its normal for the car to run shity and smoke while you are spraying. If this does not work it is probly not stuck but the motor is bad but 90% of the cars i have delt with it just takes a $2 can or carb cleaner and not a $500 iac motor

ratnin57 · 09-22-2004, 08:18 PM

We found a salvage yard close by with greasy unwashed large human beings that had a wrecked 88 Supra and it had a IAC motor on the engine. After a ride in a condemmed vehicle with no doors and only a drivers seat we finally reached the back 40 acres after bottoming out on every rut in the road. This was like a trip to a different world but they sold it to us for $35 with a money back garauantee. I will let you know if it works. Im now going to soak my ass in a bucket of ice.

Kenny back in the real world

turbomic · 09-22-2004, 08:31 PM

hey as a large greasy (most of the time) human beings I take offense.

Jeeves · 09-23-2004, 01:19 PM

turbomic,
If a PCV system is pouring out Carbon you've got bigger issues. The PCV should let out oil, and this commonly appears in the intake piping on 7M's... I've never ever seen carbon from the PCV...

ratnin57 · 09-23-2004, 05:29 PM

My friends son installed the used IAC and it worked great. Engine Idled perfect and he drove the car around last night and said it ran great. This morning I got a call and he was on his way to work and it lost power and would not accelerate. He was able to nurse it back to the house but I have not had a chance to look at it. I guess I will check trouble codes and fuel pressure.

Jeeves · 09-24-2004, 03:45 PM

There are soooo many things he could have messed up....
Oi.

ratnin57 · 09-25-2004, 06:10 AM

My friend took the car back to Toyota and the same mechanic looked at it. He said the used IAC motor was working properly but told them the Air Flow Sensor was bad. The air flow sensor changes readings when you tap on it. He refused to charge them any more labor and told the kid how to fix it. The service writer was not too happy but Im glad to see someone not take advantage of a situation.
I guess its back to the rut filled salvage yard with the unwashed greasy big guys.

Jeeves · 09-25-2004, 03:43 PM

Good Luck. Air flow meters are expensive.

ratnin57 · 09-26-2004, 04:22 PM

We were able to find a air flow sensor off a 87 Supra locally for $100. Car was still running a bit unpowered and I came by and found a miss in the engine. We removed and checked all the plugs and they looked great. The kid that owns the car said the rubber boots were missing from some of the new plug wires he put on a month ago. One of the two shops that worked on it left most of them off. (Except for the two under the throttle body that takes a lot of work to get to.) We went and bought another set of wires and boots and coated with dieletic compound stuff and the car was running light a new one last night. I hope it lasts.
Thanks for all your great help. Im working on a 86 Toyota 4WD 22RE that I bought for $350 for my daughter and I was told it needed a fuel pump and head gasket and of course as I started this project the rusty fuel lines broke off and I had to buy a fuel pump bracket and I installed new pump and it didn't run so after testing relays and ripping right side of truck apart I found the relay above the ECM that I had to remove and behind the glovebox and speaker and the dash bolts only to find it was bolted in a place tighter than a Nuns you know what. At least the relay tested bad. Im waiting on a relay I ordered. I may be back soon if this beast won't fire. My Chevys are looking good right now.