4rnr

What could be causing this. At idle my rpms surge between 900-1400rpm. Also the truck idles at 1100rpm (which seems high) The truck is a 88 4runner, v6, 5spd. Any Ideas would be great.

rngrchad

TPS=
Throttle Positioning Sensor.

Wait?? Do 88's have TPS? Hmmm maybe someone else could chime in

colsoncj

Mines doin about the same... haven't had a chance to look at it, but im thinkin its related to the EGR.... does yours make any funny noises when the idel changes?

Mine will idle at 900 then jump tp 1300 for a while, then back down to 700 so on and so forth... everytime it changes i can hear something from the EGR direction makin noise.

4rnr

No noises other than the engine rpms. one second its at 1000 next at 1400, than back. Sometimes it goes away after the motor warms up, but today it was doing it warm.

4Crawler

iTrader: (3)

Make sure the TPS idle setting is correct:
- http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

Then turn the idle down a little (bypass air screw on the throttle body sets the idle speed), as you may be hitting the ECU's fuel cut RPM. The ECU will cut fuel to the engine in certain cases, most commonly when the idle is too high, then when the RPMs drop, fuel is restored and you get the up-down variation in idle speed.

And the other thing to check is that the coolant level is topped off. At least on the 22REs, the ECU's coolant temp sender can get hit with air bubbles in the cooling system and cause the ECU to think that the engine is alternately cold and warm and switch between the fast warmup idle and normal idle.

4rnr

good info I was wondering about that sensor but couldnt imagine how it could produce these symptoms, thanks Ill check those tomarrow

colsoncj

Ok on the idle adjustment, if its the large flat head (bypass screw) that sets the idle, why is there a nutted allen set screw on the bottom that acts as a stop for the throttle linkage, almost as if it is the idle adjustment? if that is the adjustment, where should it be, and where should the bypass screw be in its range of motion when setting it?

4Crawler

iTrader: (3)

Because the nutted allen screw is the throttle stop. You set it to position the throttle plate at it's fully closed position. Generally you let the plate close, turn the screw in to contact the linkage then in 1/4 turn more and lock it in place. Then you use the idle air bypass screw to adjust the amount of air getting past the throttle plate to set the idle speed. You would set it wherever needed to achive the desired idle speed. If you find it is way out or way in, something else may be misadjusted. For example if the screw is turned all the way in and the idle speed is still too fast, there may be too much air leaking in past the throttle plate (it is not adjusted right) or there is a vacuum (air) leak somewhere in the intake letting extra air in, etc.

colsoncj

Thanks Roger, that was the info I was lookin for!

BeaterToyota

4rnr & colsoncj-

Did you guys ever get this figured out on your rigs? My '94 22R-E started doing something similar the other day, but I haven't had a chance to check it out.

It will idle just fine when I start it up, but after it gets driven a bit and I come to a stop it will jump back and forth from about 1500 to 1800 RPM. It surges every second; up and back down.

I'm thinking mine has to be a vacuum hose problem somewhere. When I step on the brake the idle drops to about 1000 and surges up to 1200 and back down again. There is some sort of vacuum line on the brake booster, right?

Anybody have any suggestions?
Thanks.

superjoe83

turn the idle down, your hitting fuel cut when the brakes are applied

phorunninduke

Chances are you have a vacume leak or something causing the high idle, dont just turn the idel down without looking.

BeaterToyota

Yeah, that's what I was thinking. It had been running perfectly, and then this started. I hadn't messed with the idle, or anythng else, at all before the problem started, so I don't think adjusting it is the answer.

superjoe83

when you press the brake pedal it sends a signal to the ecm to cut fuel if above a certain rpm so, if it only does this when the brakes are applied, thats probably your problem, you can try plugging the booster line and see if it still does it, but dont drive it with the line plugged, you wont have any power assist for your brakes, what does your truck idle at now?

chuckwhut

i'm just starting to have a similar issue...before i do anything at all, (apologies in advance for getting ready to ask such a basic question), what is the ideal idle for the 22re?

4Crawler

iTrader: (3)

Yes, turn the idle speed down, see the Toyota Trails Truck Tech column from Sep. 2004 for a full description of the problem:
- http://www.4crawler.com/4x4/TLCA_Tru...ech.04.09.html

colsoncj

I havent looked into mine yet, but mine started after i screwed with the idle, so im pretty sure mines just an adjustment problem.... lately have had bigger fish to fry like tranny fluid and a fan clutch... but its now next on the list.... will post how it goes!

Frost

Hi,
I have a similar situation my truck (87 22re) idles fine when I start it but as I drive it seems to stay at about 1500 – 2000 rpms. But if I rev it some it’ll drop back down to spec. idle. When I am stopped and it idles fine if I push the gas just a hair it’ll jump up to 1500rpm. So I was thinking it was just sticky but it only seems to “stick” open when the car is on. So my question would it most likely be a vacuum leak? Or is it possible to be a problem with my dash pot. P.s. sorry to sound like a nub but I don’t have much auto repair knowledge.

phorunninduke

TPS, the spring inside is probably gummed up and sticking.

BeaterToyota

I read the post in that link and it makes sense. I'll mess with it in the morning and see what happens. Thanks.