FJ 62 ISC problems

[PurpleFJ62]

Hi all, still working on this idle problem. Currently have a new pcv valve and fuel filter. This helped a little bit. I am running a can of sea foam thru the system right now.

I think there is some condensation on the tank from it sitting so long and never being used.

Anyways so on a cold start it runs fine, after warm up it idles around the 600-700 mark and is very rough.

So this morning I got desperate and disconnected the ISC and started her up. The engine was cold. It idles fast, as do all my other toyotas when you start them cold. About 2000 rpm, I think that is a little on the high sdie, but if it will do no damage I am fine with it. After playing with the idle adj screw I got it down a little and I took it for a nice long drive, subjecting it to some freeway and stop and go and its amazing that it does not ever go into its finiky idle thing. Keep in mind that the isc is just disconnected. I hooked it back up and started it and it ran like s***.

I think I have narrowed down the problem here, do these isc things ever cause problems for you guys?

I have been looking far and wide for mechanical problems, is it possible that its just this elec sensor?

It never made any sense, toyotas arnt supposted to have mechanical problems at 132,500 miles.

After my engine is warm, I idel in neutral at 1200 and while stopped in drive at 800.

any suggestions?

thanks -nate-

 

[ellington12]

ISC motors can go bad; they get carboned up and start sticking or they just simply wear out.

couple of things to check before condemning the ISC:

check your valve adjustment!

make sure than once you're warmed up, your oxygen sensors are functioning properly.

check for any vacuum leaks.

check for any codes if you haven't already.

you can also try this; with the ISC plugged in, tap on it a few times and see if the idle changes. if it does, your ISC is bad

you can also try to clean the throttle body, if there's a lot of gummy carbon residue in there, clean that out.

 

[pappy]

The ISC is not a sensor, it's a valve controled by the ECU. The ECU receives RPM signals from the ignitor and uses the ISC valve to by-pass the throttle body giving the motor more air at an adjusted rate. To quote from the 1988 New Car Features:

By means of engine speed signals, the ECU sends control signals to the ISC valve so that the actual idling speed becomes the same as the target idling speed stored in the ECU. Also, while the engine is warming up, the ECU, based on coolant temperature signals, sends control signals to the ISC valve based on coolant temperature to increase engine speed to fast idle.

Jon

 

[PurpleFJ62]

thanks guys. Its apparent to me that my vehicle has been modified. There was a grey wire spliced into the ecu harness. This was right behind the glove box. I think figuring out where it goes will be vcery hard. Its disconnected right now. I was getting code #11, but after disconnecting that wire the code is gone and I get the fast blinking light. All clear? Took for a test drive, seems to be ok. Have not checked the O2 sensors yeat. Will do so before lunch.

Also found a blue wire strung across engine bay. It goes from a small stud on the ign coil. I believe thats what you call it. Has big wire that connects to the center of distrubutor. Anyways it looks like it was added because its just out in the open and tied up with zip ties. In no way would toyota ever do this. It goes to the 4,5,6 cyl exhaust manifold, looks like a gound to me. There is a connector so you can split the wire w/o any tools. Like a quick disconnect, it however looks like the other factory toyota stuff. Disconnected it and no noticeable difference.

thanks and keep the info coming.

-nate-

 

[pappy]

Good luck with code 11.

Item: ECU (B+)
Diagnosis: Momentary interruption in power supply to ECU.
Trouble Areas: IG switch sircuit, IG switch, main relay circuit, Main relay, ECU.

The only wires coming off the coil should go to the ignitor. Aftermarket tach?

The grey wire was tapped into what wire on the ECU?

Pull the EFI fuse to clear the codes, take her for a putt, then check again for codes.

 

[PurpleFJ62]

never got around to checking the o2 sensors. Its amazing they are still there, the rest of my exhaust is rotted. Does anyone know where to get replacments.

I would like to put on headers and run a 3 inch pipe all they way back. OEM replacments would be fine, but I am not paying 85$/hr for some person at muffler man to fix it for me.

I never cleared the codes and still got the fast flasher, meaning all clear? I think thats what the manual said.

there is currently no aftermarket tach, no evidence of one prior.

For the last 3 months this problem has been like a ghost, I am never really able to pin point it. So ill keep this thread informed as to how it runs over the next few days.

thanks. -nate-

 

[pappy]

You might do a search. The 3FE exhaust has been discussed to death. In a nut shell the 3FE exhaust manifold is rather efficient and a header is not worth the effort. A 3" exhaust is probably overkill, and a 2.5" is probably a better choice.

The OEM exhaust, as best as I can tell, is discontinued so a muffler shop is probably your only option. The only part I could find was the cats, and they were $573 each. You have two.

http://www.oxygensensors.com sells Denso units for $88 each. You have two. Toyota list is $152.80ea, CDan price is $114.60ea.

 

[PurpleFJ62]

thanks for that info. Drove the cruiser about 25 miles today. Started to act up when I got home. I am thinking its the ISC, because the engine only acts up under load, like when slush box is in some drive gear. From my understanding the isc tries to keep the engine rpm at, or close to a constant idel speed, even with loads placed on it, like trans and ac.

Is it worth trying to take isc off and clean it, or should I just figure on getting a new one?

 

[COSkier1]

Oooh, be very careful about the ISC. Talked to Cdan last week, and it's around $450.

As for the code 11, reset it by pulling the EFI fuse, or if that doesn't work, disconnect the battery for 20 minutes (probably less, but that's what I do). I also had code 11, and it went away and hasn't come back after resetting it. I think it was related to some time when I let the battery drain down.

I'm also dealing with a funny high idle and haven't figures it out. my next step is to pull the throttle body off, the ISC, and the TPS, and test them all with a multi-meter. Do you have the FSM? There are instructions in there for testing.

If you don't have the FSM for the 3FE, you should get it. You can download it for $10 from toyotatechinfo (I think that's right) if you're willing to sit at the computer and download all the different sections.

Be sure to post up if you find a fix. I sure will.

 

[PurpleFJ62]

well I have the body/chassie heavy duty repair manual. Cool cruisers has the huge book back ordered. I am going to take a crack at it right now, ill report back with in an hour or two.


-nate-

 

[ellington12]

here's an interesting article regarding idle control valves. not Cruiser specific but a Toyota technical article.

http://www.autoshop101.com/forms/h26.pdf

 

[mkaustin]

I do believe you are mistaken about OEM exhausts being discontinued. I just order a muffler and tail pipe from John Hocker @ Sierra Toyota and the cost was 33% cheaper than getting the same work from a local muffler shop. And I'm just comparing materials. One of the few time that OEM parts from the Dealer are cheaper than aftermarket. The price for muffler, doughnut, replacement bolts (x2) and 4 exhaust bumpers was just over a C-note. Shipping from AZ to TX should be 20-30. The total from the local muffler shop was 150 for muffler and pipe + $90/hr to hang it all together.

200K from the first exhaust. I suspect that the second will out last my driving and one of my son's will have to worry about discontinued parts when it's time.

Michael R_

You might do a search. The 3FE exhaust has been discussed to death. In a nut shell the 3FE exhaust manifold is rather efficient and a header is not worth the effort. A 3" exhaust is probably overkill, and a 2.5" is probably a better choice.

The OEM exhaust, as best as I can tell, is discontinued so a muffler shop is probably your only option. The only part I could find was the cats, and they were $573 each. You have two.

http://www.oxygensensors.com sells Denso units for $88 each. You have two. Toyota list is $152.80ea, CDan price is $114.60ea.

 

[PurpleFJ62]

this is intresting stuff. Just took off my isc and did the electrical tests on it. It pulses, but barly if at all moves. Ran it thru the sequences a few times, hardly noticalbe to the eye.

The resistance checks were ok. Isint the isc supposted to move a noticable amount to change the airflow directed around the TB?

thanks for any help.

 

[Aseif007]

If I remember correctly, a "test" for the ISC is to have somebody insert the key in the ignition and another person goes and puts their ear near the ISC and when they turn the key the ISC should click. If it clicks that is good.

 

[PurpleFJ62]

ill try that tomorrow when there is some daylight. If this thing clicks then the plunger moves a good distance?

Is it possible for the TPS to cause a idle problem?

thanks for the help. -nate-

 

[ellington12]

purple,

the TPS could cause an idle problem if it's misadjusted, (if adjustable,) or just worn out. the ECU uses the input from the TPS to know whether you're at closed throttle, i.e. idle.

if you're at a stop with your foot off the gas but the TPS isn't telling the ECU that you're at idle, the ECU won't send a signal to the ISC motor.

since it sounds like your symptoms only occur when in gear, you may want to check your neutral safety switch to make sure it's sending a signal to the ECU letting it know you are no longer in park and/or neutral. the ECU should bump the idle up a little when you shift into a drive gear to compensate for the added load of the transmission.

wish i could tell you how far the pintle should actually move but i honestly have no idea.

 

[billmc]

Also, like the rest of the throttle body, the TPS gets exposed to crud from the EGR and PCV systems and tends to get so gummed up that the return spring isn't strong enough to return the spindle to the idle postion, which means the ECU thinks you still have the throttle open. Likewise the inside of the throttle body can get so crudded up that the throttle really won't close all the way.

Bill

 

[PurpleFJ62]

thanks for that info. It looks like the tps has slotted where the screws go in. So it looks like a distributor, where there is some room to twist it. I wish I could say it only acts up when the trans it in gear, but its also dose it after it warms up and is in park and neutral. I took the tps off, it was clean. Would someone be willing to show some pictures of thier set up so I could compare to mine.

I am going up the auto parts here in a minute and get some carb cleaner and clean the TB out. The return spring is very stiff. I was going thru the manual doing some resistance checks and it said open it all the way, I could barley do it, and I would not want to get my fingers in the way when it snaps back. Its got a bite to it.

I have put in a new pcv valve. The old one was a little gummy.

i have not checked the neutral saftey switch, where is it located?
thanks again, -nate-

 

[billmc]

Be careful not to use carb cleaner to clean the TPS, it can damage it. If you're testing it according to the FSM and it says open at every position then it's likely bad and needs to be replaced. That's what happened to mine.

Bill

 

[COSkier1]

Bill-
did you test your tps with it still on the truck?
And what were your symptoms?
Thanks.