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Discussion Starter · #1 ·
So I fought and fought with the idle problems on my 89 22re. Its been a year and a half with no trouble but its back and its new.

When the motor is cold, it starts right up and idles fine. When the motor is warm/hot it runs and drives just fine.

As the motor begins to warm up (just off C on the gauge) it starts hunting for its idle, nearly dying then back up to idle (there is a very symmetrical rhythm to this). Once the gauge reads about 3/8 of the way from C to H it stops and runs fine.

Somedays i get straight onto the highway and never notice it (no idle during this crucial warm up) but somedays I have to go through town to to burger king or something and it does it every time.

When I have the window down, and it is doing it, I smell unburnt fuel.

Last year I replaced both temp sending units with factory toyota parts.

Any ideas?
 

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89 YODA
89 toyota pickup sr5
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3 Posts
i had the same problem....it was my THROTTLE POSITION SENSOR get ya one of those and see if that helps. if not check for vacum leaks
 

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Cressida nut
91 Pickup (Hilux)2wd
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4,586 Posts
Do you have a tach? if so, what RPM is it cutting out at? if it's idling high it can hit decel fuel cut off (when you're over 1600 (+/- a few. I forget the exact number for the 22re) and the TPS reads that the throttle is closed, like engine braking, it'll cut fuel entirely till you get below 1300 (again, +/-)) cold it doesn't DFCO and hot it isn't idling high enough. course it won't sound like it's nearly dieing when it's doing that since it usually stays over 1k rpm.

could also be the idle control motor under the throttle body: wide open (cold) is fine and mostly closed and stable (hot) is fine but when it has to move around (lukewarm going from high idle to warm idle) it sticks. take it off and clean it out.
 

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Discussion Starter · #4 ·
thanks

Ill look at the TPS this weekend, I've already got one new in the box, from the last time it started acting up. Got my vacuum leak solved before i put the tps on, so I just left it in the shop.
 

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Soylent Green sales
rock crawler
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Do you have a tach? if so, what RPM is it cutting out at? if it's idling high it can hit decel fuel cut off (when you're over 1600 (+/- a few. I forget the exact number for the 22re) and the TPS reads that the throttle is closed, like engine braking, it'll cut fuel entirely till you get below 1300 (again, +/-)) cold it doesn't DFCO and hot it isn't idling high enough. course it won't sound like it's nearly dieing when it's doing that since it usually stays over 1k rpm..
Idle surge caused by the idle rpm set too high and the fuel cutoff kicking in (what he's sort of describing above) only occurs when the brake pedal is depressed.

A simple thing like low coolant level can cause it, or a gunked up Aux Air Valve.
 

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rock crawler
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To answer the next question, AAV :

 

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Discussion Starter · #7 ·
I will check the coolant and the AAV. I know it is old. When I had the motor built a year or two ago, I had a mess of problems, and went through 3 different throttle bodies. The air valve on it now came with one of the used TBs. In fact if i remember that was part of the problem. My throttle body has a different configuration for attaching the AAV, maybe three bolts instead of two, or maybe the other way. I'll try to get some pics tomorrow.
 

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Cressida nut
91 Pickup (Hilux)2wd
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4,586 Posts
Idle surge caused by the idle rpm set too high and the fuel cutoff kicking in (what he's sort of describing above) only occurs when the brake pedal is depressed.

A simple thing like low coolant level can cause it, or a gunked up Aux Air Valve.
I just double checked the TSRM and it says nothing about having the brake pedal pressed. 1993 tsrm page EG1-219. it just says open the throttle to bring the revs to 2500 then let go and listen to the injectors that they aren't opening. the TSRM for cressidas and supras says unplug the TPS and open the throttle and watch RPMs. Some systems do require the brake pedal to be pressed to engage DFCO...just not OBDI Toyotas.

22RE 2wd auto
fuel cut: 1300
fuel return: 1000

22RE others
fuel cut: 1900
fuel return: 1600
 

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I just double checked the TSRM and it says nothing about having the brake pedal pressed. 1993 tsrm page EG1-219. it just says open the throttle to bring the revs to 2500 then let go and listen to the injectors that they aren't opening. the TSRM for cressidas and supras says unplug the TPS and open the throttle and watch RPMs. Some systems do require the brake pedal to be pressed to engage DFCO...just not OBDI Toyotas.

22RE 2wd auto
fuel cut: 1300
fuel return: 1000

22RE others
fuel cut: 1900
fuel return: 1600
^^^^
Wrong.
In order for that fuel cut off system to kick in, the brake pedal does have to be pressed.
go drive your truck, get it in fourth going roughly 40-45, let off the gas pedal, then press the brake and tell me that the engine doesnt bog down.
 

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Discussion Starter · #10 ·
Well, I added 3 8 ounce bottles of water to the radiator. I've only driven it once since then, but one this one trip home, it didn't have the problem.

I thought coolant was about the only thing it didn't leak.
 

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Cressida nut
91 Pickup (Hilux)2wd
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4,586 Posts
^^^^
Wrong.
In order for that fuel cut off system to kick in, the brake pedal does have to be pressed.
go drive your truck, get it in fourth going roughly 40-45, let off the gas pedal, then press the brake and tell me that the engine doesnt bog down.
Go read the TSRM. I've done it on my 91 pickup, my cressida, and my 87 S10 and all of them you can feel when the fuel cuts and comes back (at the rpms specified by the manuals).... without any input of the brake switch. stay in gear while decelerating from over 2k rpm all the way down to idle (without using the brakes) you'll feel two light bumps/lurches. first, as fuel cuts back in, again when the rpm crosses the desired idle point and torque changes from decelerating (IE engine braking) to accelerating. You have a PM of the links since we aren't supposed to post publicly from the TSRMs
 
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