1990 Toyota 4x4 Idleing problem
#23
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Join Date: Dec 2007
Location: Rochester, Washington
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Maybe someone can post a pic of theirs to get an idea where it's suppose to be, but really it will be different after it is all cleaned anyway. Mine is for a 22RE so it would probably be different, otherwise I would post a pic of mine.
#24
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"There's information that relates that if the idle speed is too high, the ECU will not fire the injectors when the brake pedal is pressed in order to assist in engine braking. I cannot verify this but it comes from 4Crawler so I'll assume it to be true. If the brake booster has in fact been checked and is operating properly, the next time you get surging when pressing the brakes, disconnect the plug from the brake switch under the dash and see if it surges when you press the brake pedal down. If it doesn't, I think you can say the idle is too high. If it does then it's back to square one and looking at the booster. (Don't forget to plug the switch back in.)"
I never disconnected my brake plug, but I did turn my high idle (1,500rpm - after thottle body cleaning) back down to 800-850rpms, and the surging problem vanished.
#25
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Mine was open (0 ohms) so it was royally screwing my computer up. Turn the throttle plate full open, my new working TPS reads I believe 2500k ohms.
Here is a guide, I found it useful with the exception of wide open throttle reading being incorrect (it didn't match my brand new one).
http://www.4crawler.com/4x4/CheapTri...#TPSAdjustment
Just follow my directions really quick and see what reading you get before diving further into it. Let us know.
A new unit was like $120 at napa... make sure they give you the correct one, they have the wrong p/n in their system when I went for mine. Either the connector will be wrong, or the rotating part that mates to the throttle body will be 45deg in the wrong direction.
Last edited by LS1Steve; 03-05-2009 at 08:06 PM.
#26
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I will check the TPS to make sure it is adjusted properly as i just replaced it, as for the brake swith already tried it it made no difference at all. I am in the process of getting cooling system working again flushed the cooling system "nasty S**T" got thAT DONE just in time for the water pump to go out, also changed the fuel filter also in bad shape no change, new intake gaskets and a cleaan intake no change, but did find the hissing sound i am hearing when i put on the brakes is the power stearing pump but cant find any vacumme leaks there
#27
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I already tried to unplug the brake pedal switch, no change. I changed all intake gaskets, no change. New TPS, no change. flushed cooling system(nasty S**t) cahanged thermostat got done just in time for warter pump to go out, will post results when fixed
#28
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Well, I finaly got the truck back together. New timing belt, water pump, oil pump. I drove it around for a little while last night, all seems to be working good, the idle still wants to jump about 500-600 rpm when i shift gears
#30
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i think im getting closer to the end the truck is now running realy good with the exception of ... when starting the truck it idles perfect at around 1300 rpm, then it will drop to 500 rpm until the truck completely warms up when it will idle where it is suposed to be at 800 rpm I have double checked the timing and the TPS adjusment any other ideas or am i just going to have to live with this one???
#31
I know I'm new and this is a old post. But one I needed yesterday. I had the same issue. And think I got it fixed. So I figured I'd share what happened and maybe help someone else out.
Well about 2 months ago I needed to replace the head gaskets. You might know all the work needed for that. So anything was possible. Everything was running good I drove about 3000 miles. Well went 4wheeling the other day. BAM surging idle after. Well did a lot of searching on that issue.
This morning I did all the tests. Timing was dead on. Idle was 900. TPS working and was never touched so setting it wasn't needed. Vacuum lines all good. I did the booster test listed here. All pasted. Still had the issue. Then I watch a YouTube vid on the issue but on a 22r. It was from silicon clogging the water from flowing right to the TB. So I pulled that apart. On the 3vz its from manifold to the TB. Nothing was there. Well I desided to power flush the system. Not really a good idea but nether is ripping everything a part if I need to work later tonight.
Leaving the TB hose off the manifold connection. I removed the heater hose. Only the left (driver) side. Hook my watering hose with a 1/2 inch fitting to the heater hose. Turned heater switch to heat. Then turned on water low. Flushed heater core and watched as water flowed threw TB hose and manifold. I then turned heater to cold. Shouting core off. Water flowed from manifold good but not from hose on TB. So I used thumbs and plugged hose and nipple. Then when pressured to the point water was running to radiator overflow. I released manifold first. Repeated and released TB. Repeated that a few times. Water was flowing even now out of both. I then turned off water. Replaced hose on manifold. Turned on hose till I heard water going in overflow and turned it off. Removed hose and fitting. Replaced heater hose and turned heater to hot. Started the truck and let it get to temp with heater on high. Then aplyed brakes. Nothing! Let it cool down checked water level. Still good. Idled it back up and still no surge. Not its time to go for a drive and see how things really work under driving conditions. But I wanted to type this when it was fresh in my head. I use this site a lot but never had anything to offer till now. So I hope this helps someone. I'll be back in a few hours to say if problem is still going or is gone.
Well about 2 months ago I needed to replace the head gaskets. You might know all the work needed for that. So anything was possible. Everything was running good I drove about 3000 miles. Well went 4wheeling the other day. BAM surging idle after. Well did a lot of searching on that issue.
This morning I did all the tests. Timing was dead on. Idle was 900. TPS working and was never touched so setting it wasn't needed. Vacuum lines all good. I did the booster test listed here. All pasted. Still had the issue. Then I watch a YouTube vid on the issue but on a 22r. It was from silicon clogging the water from flowing right to the TB. So I pulled that apart. On the 3vz its from manifold to the TB. Nothing was there. Well I desided to power flush the system. Not really a good idea but nether is ripping everything a part if I need to work later tonight.
Leaving the TB hose off the manifold connection. I removed the heater hose. Only the left (driver) side. Hook my watering hose with a 1/2 inch fitting to the heater hose. Turned heater switch to heat. Then turned on water low. Flushed heater core and watched as water flowed threw TB hose and manifold. I then turned heater to cold. Shouting core off. Water flowed from manifold good but not from hose on TB. So I used thumbs and plugged hose and nipple. Then when pressured to the point water was running to radiator overflow. I released manifold first. Repeated and released TB. Repeated that a few times. Water was flowing even now out of both. I then turned off water. Replaced hose on manifold. Turned on hose till I heard water going in overflow and turned it off. Removed hose and fitting. Replaced heater hose and turned heater to hot. Started the truck and let it get to temp with heater on high. Then aplyed brakes. Nothing! Let it cool down checked water level. Still good. Idled it back up and still no surge. Not its time to go for a drive and see how things really work under driving conditions. But I wanted to type this when it was fresh in my head. I use this site a lot but never had anything to offer till now. So I hope this helps someone. I'll be back in a few hours to say if problem is still going or is gone.
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