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1994 5sfe Camry MT
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Discussion Starter · #1 ·
Hi all. I got this 1995 Corolla some 6 months ago. So far i've changed oil, timing belt set and all seals on tb side, thermostat, radiator, spark plugs.
Problem is i can't get rid of the high idle. It is a base throttle body, without the iac valve, just the tps. It is always between 1100-1400 rpm. Except sometimes for a quick stop for a few minutes (engine warm), then after i start the engine it sits arround 750 rpm and even surges for maybe 1 minute, and it goes up to 1100. Intake hose was cracked, i fixed that. No obvious air leak. Cleaned the throttle body (without removing it). So far nothing changed. The idle adjust screw is at 0 point. I dont want to mess with the tps and cable side of the flap. Any suggestions?
Thanks

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I think the power steering is also capable of raising the idle RPMs.

You can try capping off the vacuum lines to see if that ferrets out a non-obvious vacuum leak.
 
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Over the years of owning many Toyota’s, I have found high idle problems caused by leaking vacuum lines several times. You will probably find dried out hoses with cracks on the connected ends or where the hose is bent on an angle.
 

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Discussion Starter · #4 ·
So far i can't find any obvious leak. I sprayed it with brake cleaner and no obvious difference.
This morning outside temp. is slighly lower (below 0 C), so it even raised to 1800, and even started to go up and down, when standing on a red light.
What i realised, when i got at work, is that the small hoses that should take coolant to the TB, to warm it up, are no near warm, i can hold them by hand. Maybe it is clogged, and the valve can't warm up and doesn't open (it has the mechanical iac walve, not electrical). That is my best logical guess. I'll try to clean it up, without removig the TB or dissasemblying, i have no spare gaskets. Anyone has experience with the aux valve on the TB?

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So far i can't find any obvious leak. I sprayed it with brake cleaner and no obvious difference.
This morning outside temp. is slighly lower (below 0 C), so it even raised to 1800, and even started to go up and down, when standing on a red light.
What i realised, when i got at work, is that the small hoses that should take coolant to the TB, to warm it up, are no near warm, i can hold them by hand. Maybe it is clogged, and the valve can't warm up and doesn't open (it has the mechanical iac walve, not electrical). That is my best logical guess. I'll try to clean it up, without removig the TB or dissasemblying, i have no spare gaskets. Anyone has experience with the aux valve on the TB?

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Sounds like you might have located your problem! Good luck...
 

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Discussion Starter · #7 ·
Sounds like you might have located your problem! Good luck...
Yes i did. After i poured warm water to warm up the valve body, and after a few secconds and a cup of water, it started to go down and cemented itself to 750-800. So it is working, which is the good news, but the coolant passage is likely clogged. Before i get back from work, il do it again, and hope with some higher rpm driving it will unclogg itself. If not i'll try to clean it, and the hoses, without taking it off. If not....i'll figure something out, silicone will do the job for the gasket.

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It could be clogged, or it might just be air-locked.
 

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Yes i did. After i poured warm water to warm up the valve body, and after a few secconds and a cup of water, it started to go down and cemented itself to 750-800. So it is working, which is the good news, but the coolant passage is likely clogged. Before i get back from work, il do it again, and hope with some higher rpm driving it will unclogg itself. If not i'll try to clean it, and the hoses, without taking it off. If not....i'll figure something out, silicone will do the job for the gasket.

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Did you find a resolution to this? My car has twice not raised the idle when being cold-started in sub-freezing temperatures. Both times I hit the accelerator and then the revs came up and stayed up until warm-up, like normal. The second time it did this, it actually triggered the CEL. Today I read the codes and got a PO501 (I think it was) for the IAC, and also a PO136 for the upstream O2 sensor I just replaced - but I can see the 136 being because maybe the injectors were squirting more fuel, but the IAC wasn't letting in more air?
 
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Discussion Starter · #10 ·
Did you find a resolution to this? My car has twice not raised the idle when being cold-started in sub-freezing temperatures. Both times I hit the accelerator and then the revs came up and stayed up until warm-up, like normal. The second time it did this, it actually triggered the CEL. Today I read the codes and got a PO501 (I think it was) for the IAC, and also a PO136 for the upstream O2 sensor I just replaced - but I can see the 136 being because maybe the injectors were squirting more fuel, but the IAC wasn't letting in more air?
No, i still haven't found the time do fix it, it was cold couple of weeks. But i hope to do it soon. But, since you mentioned you had the code for the IAC, i suppose yours has the electric IAC valve, mine is a mechanical thermostat like type of IAC. If you have the electric type, there are many videos of how to clean it. Maybe it has collected some dirt or carb bildup. Easy to clean. And after tapping the pedal all went well.
But, mine is obd1. You mention p0501 and p0136, what engine and year is yours? The 501 is listed as a generic code for vehicle speed sensor? Maybe there is no connection to the IAC, maybe just a coincidence.

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I might've gotten the code wrong, but it definitely said IAC.
Mine is a 1997 with the 7A-FE and automatic. It is OBD2.
 

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Discussion Starter · #12 ·
Well if it starts to do it more often, a good clean should do the job.

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My 96 DX has exactly the same behavior It idles up around 1100 and only after it is completely warmed up and I shut everything off and don't touch anything Will it sometimes drop back down to around 700 where it belongs. My car, I took a throttle body from the junkyard and meticulously polished and cleaned it out got new gaskets and observed full functionality of the thermomechanical valve and it has good flow going to the water jacket but still does the same thing.
 

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Discussion Starter · #14 ·
Well finally i got the time to try and fix it. Found the problem, but did not fix it. So, as i suspected, the coolant passages to the TB were/are CLOGGED badly....so warm coolant can't go iside to warm the body and valve. I could not clean the insides, just the pipes. I have do take it apart for a good clean. It was very thick gunk inside. I think that at some point someone tried to stop a coolant leak, and put "something" to seal it. Since the TB is higher than the head and has tight passages, all of it went in and clogged it. It is so thick, that the coolant can
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t push it. I made a photo, but will make more when i take it apart.
 

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Discussion Starter · #17 ·
What is that yellow item?
Sorry for the late responce. Somehow i got signed out. The grey thing is a sample of the gunk. The yelow item is actually the first thing i found next to me, it is a juice straw i found to try and dig all the gunk. No special tool. Haha.. but i clould not clean the inside, just the pipes. It was cemented. I have to take the TB out and clean the whole thing. I must find some liquid solvent to disolve the gunk.
I'll post more and better pics when i get to it. Cheers

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Discussion Starter · #18 ·
Well i finnaly found the time to take the throttle body out for a nice cleaning. And boy was it clogged... The only way was to take apart the idle valve and it was CEMENTED with gunk. I still don't know what it was, probably some 'stop leak' additive. And the only thing it stopped was coolant flow. I mean, i tried a few degreasers, or green lemon fluids, not sure how they were called, and nothing. After i took it apart, i took a small flat screw driver, and started digging. I managed to take most of it out, and now the coolant passages of the TB are free. Now the throttle responce is better, and the idle is almost ok. But i noticed a new problem, regarding thw high idle. After i started the engine, and was checking for coolant leaks from the TB, i saw that the no.4 injector was a little wet, the o-ring is leaking fuel. But also i have a vacuum leak from the bottom injector gasket. So one problem solved, next is an injector gasket set replacement. I ordered the gaskets and will post the outcome. Might take me a while, since shipping time will be more that 30 days. I hope it won't start leaking more....
There are some photos of the gunk i managed to take out.
Cheers


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