RylerTust

During warm start/ idle, runs rough and low idle. Just started it and when I was doing it I pulled the tps plug and idle restored to normal. BUT if I short the connector to check timing, it's fine, idle drops like its supposed to. This issue is only idle, no running problems. I also have a fuel ratio gauge, and when this is happening its leaning out really bad. What's wrong if pulling the plug on the tps helps but the timing check works too? Need some help guys this problem is really annoying and kinda scares me haha. Any help is greatly appreciated. Thanks.

1990 toyota 4runner
22re
5speed
A/c
P/s

Rerunn

That truck should have a fuel pressure up vsv. It'll be on top of the valve cover at the back with a vacuum hose running to the fuel pressure regulator. Start there...I have the same problem and have no confirmed fix.However that is where I would start.

RylerTust

I checked that doing all tests but the one with the volt meter, and all tests the vsv checked out fine. I unplugged the tps and drove it two miles to my brothers house and it ran like a dream. Only differance was it didn't go to rich mode when i went to WOT and it didnt go to lean mode when I let off the throttle while in gear. Any other ideas??
Thank you!

Rerunn

Hmmm have you adjusted the tps?

RylerTust

Plans were to ohm out the tps today but some things came up and now I won't have the time this weekend. Any more ideas keep em coming and ill give them a try when I get the spare time. Thanks again rerunn, and whoever else may chime in

Rerunn

I have the same problem with mine. But only got bad til top end was rebuilt including a cam. Im currently doing some Guinea pigging of my own and so far its better but not cured

SPARKS89

iTrader: (1)

There's another thread here that's discussing this exact problem. I'm also having the same issue with my truck. Cold start and running is fine, but if I restart the engine after sitting for 10-15 minutes it will idle around 400-500. Once I tap the throttle it will hold right around 750 RPM.

According to the other thread it's the temperature switch that's the problem. It's Toyota part # 89428-26020. The BIGGER problem is that this part is discontinued and nobody can seem to find the replacement part number. I'm going to take my temperature switch out tomorrow and clean it and see if that will fix the problem. It's supposed to be on the front of the engine just below the throttle body and to the right (center of the engine) a little. It should be next to the temperature sensor for the gauge. I'm not sure exactly which one is which, but I'm going to clean them both just to make sure I got it. It won't hurt to clean both of them anyway. I'll report back after I find out if that fixed the problem or not. Hopefully it will help me and you!

Rerunn

That tsb stopped in 88. There are 2 part numbers for this tsb one is that temperature switch which is still available. The other is a reflash for the ecu to make the cold start injector kick on at a different temp. That reflash is no longer available its just labeled as a part number.

SPARKS89

iTrader: (1)

So what is the part number for the switch? Will that solve the problem or would we need to get the ECU reflash as well?

Side Note: I didn't get to work on mine today...ended up having to go out of town. Results to follow when I do get to it.

Rerunn

I'll try to pull the tsb up at work and confirm that part number. However....this fixes 22re and 22ret to 87 or 88!!!! After that they SHOULD have fixed the problem so I'm not sure if this would be a confirmed fix for models after this year. I may try to Guinea pig the part and see what happens. As far as the ECU reflash you can forget that being available

SPARKS89

iTrader: (1)

If it was fixed after 88 maybe the switch is bad or just needs to be cleaned. I'll work on mine too and see what I can find about procedures to test it. Thanks for the additional info!

Rerunn

Switch being bad could very well be a possibility

RylerTust

Here's my update. Haven't checked anything. Becoming very intermittent. Sometimes it's lean and low, some times it's just lean, sometimes it's just low. Drove it all the way to Lucerne on Sunday, didnt do it once. Stared it up and went to work today, every time I wast on the gas (after it warmed up) it was leaned all the way out and idling at 500. If I gently touch the throttle, it goes to normal. SOMETIMES. I think the tps has a dead spot at the idle position or it may be out of adjustment.

RylerTust

Update. Adjusted tps. Checked out fine I think. Couldn't get it to read anything when I used feeler gauges? I don't know what I was doing wrong. The idle and WOT readings were in spec kinda. Idle was .82 I think. What I read on here says that's in spec. Took it for a test drive, ran FANTASTIC! For about 10 minutes. Had crazy power and I barey had to touch the throttle! Then I came to a stop light and the idle dropped again. Didnt lean out this time. But it dropped real low. Then back to how it used to be. I'm lost. Maybe the tps is bad? Anyone in the yucaipa area good with these?

Rerunn

Hmm didn't idle drop when you hit the brakes? Could be vacuum related

RylerTust

It happens when I hit the brakes or not. Idle Does seem to know when I'm about to come to a stop, though. It gets worse and lower the closer I get to being completely stopped.

Rerunn

Hmmm man this is getting tricky...gonna have to dig in the files in the back of my brain on this one!! The leaning out I'm not sure on yet. As for the low idle could be iacv, gummed up tb, something intake related in my mind. Have you tried doing an induction clean?

RylerTust

I pulled the tb to clean it today while I adjusted my tps. Pulled the iacv inspection cover to clean it that way, didnt wanna pull the whole iac cause I didn't have a gasket. Did seafoam and all that. Can't find an air leak anywhere. I should just get my hands on an iacv gasket and pull it and check it. My coolant is just too clean to see that being dirty.

RylerTust

NEW DEVELOPMENT! Just did the second seafoam treatment. During, my fuel started being cut while I'd race the engine. The "engine lope" problem so many people have with this engine. Would only do it while in neutral. Drove it up the street and it did NOT cut fuel. Came home, disconnected the battery for 30 seconds. Plugged it back in, same problem. So I disconnected my tps, idle smoothed out, and engine lope would NOT happen with the tps unplugged. Da hell is dis all 'bout? Should I just break down and buy a tps? All signs are pointing to it for me. Any input anyone?

thefishguy77

iTrader: (1)

I believe the FSM has a detailed way of testing to see if yours is bad and I am sure a google search of how to test it will turn up many links on yotatech. Also make sure your follow the FSM install instructions on the install procedure.