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Diagnosing this temperature related idle issue. And AC idle up...
Ok so I’ve been tying to trace down why my truck idles like it does but have had no luck.
94 runner 22re 4x4 manual.
When its warmed up I adjust to 750 and it runs nicely.
Then if I go somewhere and shut it down and shortly restart it, or even just when I get there the idle is down to 550. If I adjust to compensate the idle screw then other times it will be idling at around 1000. If I do that then when I cold start it idles too high.
I pulled the intake manifold and cleaned it as well as the other sensors on the intake today. I planned to pull the entire plenum and deep clean both pieces but when one bolt for egr snapped off and second felt ready to do the same I stopped and put it back together.
Another issue is that the ac does not idle up unless i close the ac idle up adjuster down and then open it. Then it idles up nicely but won’t do it on it’s own. I’m assuming it’s the diaphragm which is nearly impossible to find for a fair price even used. Seeking parts truck now. I’m considering finding a diaphragm that fits and cutting it open and swapping. I know one guy did this successfully with a camry idle up diaphragm.
other issue, seems to be pinging in 4th and 5th under load and low rpms.
Love this little truck and want to take good care of it.
Really cant complain it is reliable and everything works just want to get it dialed in.
Change your oil
Replace all vacuum tubing with oem or from 22reperformance
Check your TPS setting. Then verify it's working by setting the timing jumper. Idle should drop. Means TPS is working.
Set that warm idle to 850 (buy a 10 USD digital rev laser counter)
Set timing to 5°
Take out the jumper.
Also make sure your throttle cable runs smooth and is not binding.
X2 on the checking your TPS is adjusted properly. When I was battling an inconsistent idle issue it was because my TPS was out of adjustment, followed the instructions on 4Crawlers site. https://www.4crawler.com/4x4/CheapTr...PS/index.shtml
Specifically, the 10 steps outlined by "Frankenyota". It worked perfectly for me, fixed my idle, and allowed me to check my base timing per the diagnostic jumper.
Change your oil
Replace all vacuum tubing with oem or from 22reperformance
Check your TPS setting. Then verify it's working by setting the timing jumper. Idle should drop. Means TPS is working.
Set that warm idle to 850 (buy a 10 USD digital rev laser counter)
Set timing to 5°
Take out the jumper.
Also make sure your throttle cable runs smooth and is not binding.
Would be a lot faster and easier to just put the diagnostics jumper in and check for a steady flashing (no codes) CEL. This will tell you if your IDLe signal switch is closed right away.
There is an idle air bypass in your VAFM, make sure it's clear of things like wasp nests and other blockage.
There is another passage (used by your idle screw), check this.
There is the actual iacv, which is mounted to the underside of the throttle body. If this is getting bad power from the ECU it will be erratic. It also relys on engine coolant flow thru it.
Finally or maybe firstly, your vacuum lines need to be in good shape.
A common issue is the throttle plate not returning to its relaxed position, this can be due to binding linkages or worn out shaft or shaftways.
You mentioned sensors on your throttle body, you're going to have to elaborate. We're only aware of the tps and you probably don't want to try cleaning that if your not prepared to out a new one on (most attempts only make it worse).
Change your oil
Replace all vacuum tubing with oem or from 22reperformance
Check your TPS setting. Then verify it's working by setting the timing jumper. Idle should drop. Means TPS is working.
Set that warm idle to 850 (buy a 10 USD digital rev laser counter)
Set timing to 5°
Take out the jumper.
Also make sure your throttle cable runs smooth and is not binding.
Oil is changed 500 miles ago
Ive been considering the new vacuum lines
is there a simple way to test for vac leak like spraying starter fluid around and listening for idle fluctuations like on a dirtbike?
Im gonna check tps today. It seems to be mostly temperature related honestly. Like when it’s hot (engine or outside temp) it idles too low. When it’s cooler (again both) it idles perfect
frustrated that no one rents timing lights and I can’t find anyone that has one. I can’t spend 50 on something I’ll likely use once and may not even need adjusting!
Would be a lot faster and easier to just put the diagnostics jumper in and check for a steady flashing (no codes) CEL. This will tell you if your IDLe signal switch is closed right away.
There is an idle air bypass in your VAFM, make sure it's clear of things like wasp nests and other blockage.
There is another passage (used by your idle screw), check this.
There is the actual iacv, which is mounted to the underside of the throttle body. If this is getting bad power from the ECU it will be erratic. It also relys on engine coolant flow thru it.
Finally or maybe firstly, your vacuum lines need to be in good shape.
A common issue is the throttle plate not returning to its relaxed position, this can be due to binding linkages or worn out shaft or shaftways.
You mentioned sensors on your throttle body, you're going to have to elaborate. We're only aware of the tps and you probably don't want to try cleaning that if your not prepared to out a new one on (most attempts only make it worse).
Ok so ive jumped the the diag and it is blinking steady four times then gap then one blink then off
so
1 2 3 4 - 5
idle did Not seem to change at all
cold start injector is what i cleaned up and did not touch tps as i know it’s sensitive!
Would be a lot faster and easier to just put the diagnostics jumper in and check for a steady flashing (no codes) CEL. This will tell you if your IDLe signal switch is closed right away.
There is an idle air bypass in your VAFM, make sure it's clear of things like wasp nests and other blockage.
There is another passage (used by your idle screw), check this.
There is the actual iacv, which is mounted to the underside of the throttle body. If this is getting bad power from the ECU it will be erratic. It also relys on engine coolant flow thru it.
Finally or maybe firstly, your vacuum lines need to be in good shape.
A common issue is the throttle plate not returning to its relaxed position, this can be due to binding linkages or worn out shaft or shaftways.
You mentioned sensors on your throttle body, you're going to have to elaborate. We're only aware of the tps and you probably don't want to try cleaning that if your not prepared to out a new one on (most attempts only make it worse).
Ok so ive jumped the the diag and it is blinking steady four times then gap then one blink then off
so
1 2 3 4 - 5
idle did Not seem to change at all
cold start injector is what i cleaned up and did not touch tps as i know it’s sensitive!
Could I just need to adjust the tps or is it fried?
if it is just not adjusted properly would I do throttle stop screw first?
if it’s fried is it a bad idea to get one from ebay there’s a lot of them for like$25 picture with toyota box probably scam lol
usually they dont show top of sensor and when it’s shown with denso and part number it’s 90$
still $90 is less than a duralast one and for oem. So if you guys give the word then I’ll probably pull the trigga get her running right
Yes it needs adjustment, looks like someone just slapped it on and tightened it up.
Do not touch that throttle plate stop screw, do you have evidence it's been screwed with or something? This screw locates the throttle plate in the body, it's not meant for adjustment of idle speed. You adjust idle speed by the air bypass screw that's built into the throttle body.
I wouldn't suggest buying a $25 tps off ebay. That ceramic circuit board inside alone costs more than this IN China..
Did you check the rest of the resistance? Does ohms on VTA sweep cleanly from closed to open, it's probably fine.
You don't need to get real fiddly with the tps, see my post above where I went thru cleaning and tweaking the adjustment to get the highest full throttle voltage I could.
Your basically just getting the two parts to touch, throttle plate touches sensor, cinch it down and make sure IDL opens and closes when you put the correct size feeler in.
Yes it needs adjustment, looks like someone just slapped it on and tightened it up.
Do not touch that throttle plate stop screw, do you have evidence it's been screwed with or something? This screw locates the throttle plate in the body, it's not meant for adjustment of idle speed. You adjust idle speed by the air bypass screw that's built into the throttle body.
I wouldn't suggest buying a $25 tps off ebay. That ceramic circuit board inside alone costs more than this IN China..
Did you check the rest of the resistance? Does ohms on VTA sweep cleanly from closed to open, it's probably fine.
The tps actually has the yellow paint on the screws looks like it’s never moved. So does the throttle stop screw. I only wondered on the throttle stop screw because I watched a video where he adjusted and his truck would change idle when jumping the diag panel where previously it would not
I’ll start with checking the vta for smooth operation from closed to wot and then attempt to adjust.
If I don’t get it then I’ll try the voltage ecu method just not into moving that unnecessarily.
If I have to replace then I’ll go oem on this part since it’s lasted 25 years already!
If I don’t get it then I’ll try the voltage ecu method just not into moving that unnecessarily.
...
Like I said that is over kill and was just me trying to tweak the throttle signal (related to a specific issue on my turbocharged engine setup).
I don't recall my 94 having any of those paint marker marks, and it was certainly never touched.
Somewhere there is a spec for the throttle plate adjustment, I don't recall it in any great detail other than I THINK it's like 1-2mm which keeps it from wedging in the throttle body.
Good news managed to adjust the tps to spec! It’s a hairline between the idl test 2 and 3 showing resistance test 2 and going infinite test 3 but it’s there. No dropout through throttle adjustment.
Jumped the diag and the idle dropped so can now set timing as soon as find a timing light.
It still showed 41 tps code so I pulled neg off battery for a few minutes re connected and rechecked and now a steady blink for all clear.
Now just gotta fix the ac idle up. It works when i close idle up screw and then open it but will not work on it’s own.
Is there a way to test the diaphragm to see if it’s working correctly?
i have the online fsm but it’s really tricky finding anything based off the descriptions I’d love a pdf copy of the manual old school scroll style.
Now just gotta fix the ac idle up. It works when i close idle up screw and then open it but will not work on it’s own.
Is there a way to test the diaphragm to see if it’s working correctly?
.
Sounds like it's sticky? Clean it and hope it doesn't disentigrate, if it breaks it needed replacing anyway (can still get some models from the dealership, they all work the same. There is a recent thread with some activity that gives some part numbers.)
So it works like this. When the VSV (AC switch on, AC clutch energized by AC amplifier) applies vacuum to the diaphragm, diaphragm moves and air bypasses the throttle plate. This air is limited by the valve adjustment (big screw).
So there is one failure method where PCV gases build up in the bypass, running some solvent thru it might clear this up. A secondary effect of the buildup is that it caused the valve to get cocked to one side and its started to deform, that your not going to fix with solvent it'll need replaced or repaired.
Right so again you're at a point it's already not working, any cleaning or disassembly can only make it better or obvious it needs replaced.
No luck just with cleaning it but I found a solution on another forum.
Older toyota van has one that threads into 22re manifold. Simply split with a T to downsize the large line and power steering line since that’s what’s going on inside the diaphragm tubing anyway.
About $30 for everything should be dialed in a week or so.
Sep 27, 2019 | 12:06 AM
