Throttle Body and PCV valve/hose Removed and Cleaned. Revving at high RPMs consistently.

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yeti2

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I removed and cleaned the throttle body on my 1999 LC. My car has 270,000 miles. The Throttle body had lots of carbon buildup. I also unscrewed the PCV valve hose that connects the intake to the PCV valve on the top of the throttle body and removed tons of sludge from the inside. It was almost completely blocked off by built-up sludge. I scrubbed and cleaned the inside with a pipe cleaner as well as the holes and lines to remove as much gunk as possible. I'm not sure if I damaged the PCV valve while cleaning, but there didn't seem to be anything broken. After I put everything back together, I started the car and it started revving from 2000 rpm to 3000 rpm. After doing a little troubleshooting I read somewhere that I should turn the car on and let it run for 3 minutes and then off for 1 and repeat until it throws a code or calms down. I did it many times and saw some change in rpm. It is now revving back and forth between 1500 rpm and 2000 rpm. This revving is consistent and has the same pattern. I repeated the cycle of turning it off and on many times, but the rpm hasn't gone down anymore. How can I fix this problem and get it to a steadily idle?
 
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It will take time to relearn the idle. How high the RPM is?
 
nissanh said:
It will take time to relearn the idle. How high the RPM is?
Click to expand...

It bounces from 2000 to 1500 up and down. How long do I need to wait for it to learn? how can I help it learn?
 
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If you haven’t reset the ecu, please do so by disconnecting battery and reconnecting after a few minutes. Also while it’s disconnected, clean MAF as well. That will bring the system back to the factory spec
 
If you cracked the air intake that runs from the filter housing to the throttle body, it will do that. Make sure there are no leaks there.

Would happen on 80-series trucks a lot.
 
slopppy75 said:
If you haven’t reset the ecu, please do so by disconnecting battery and reconnecting after a few minutes. Also while it’s disconnected, clean MAF as well. That will bring the system back to the factory spec
Click to expand...
Disconnecting the battery and resetting the ecu didn’t do anything for me. Thanks for the suggestion
 
super90 said:
If you cracked the air intake that runs from the filter housing to the throttle body, it will do that. Make sure there are no leaks there.

Would happen on 80-series trucks a lot.
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The gasket between the throttle body and the metal air intake for the engine was in pretty bad condition but I didn’t have another one to replace it with. It was running decent with the bad gasket before that. Going to keep trying to reset the ecu and try and let it adjust but if the problem persists I’ll have to resort to taking everything apart again….👎
 
yeti2 said:
The gasket between the throttle body and the metal air intake for the engine was in pretty bad condition but I didn’t have another one to replace it with. It was running decent with the bad gasket before that. Going to keep trying to reset the ecu and try and let it adjust but if the problem persists I’ll have to resort to taking everything apart again….👎
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It shouldn't take much more than 2-3 start cycles to get the engine to idle back normally after the reset. Also it will typically just rev high, not bouncing around like you described. I think you are up against another issue, just not sure what.

You mentioned a possible broken PCV, I think you could just remove it again and give it a shake, Shouldn't it be rattling if it's all clear? Suprised to hear how much gunk was built up in there, I wonder if you broke something loose that is now clogged somewhere? I am not too familiar with our TB's so not much help here.
 
Update: I removed the throttle body again. I took out the APPS when I cleaned it so I might have put that back in wrong. I put it back in the way it seems it should go. Everything seems normal. It’s really hard to tell why this problem is happening! 🤬 It’s also hard to tell if I have an air leak anywhere. Can anyone give me any more tips or suggestions on things to try next while my throttle body is out?
 
old fashioned vacuum leak check is using carb cleaner. Spray it on the suspected area ( pcv hose, tb gasket and etc ) while idling and see if engine rpm changes. You have to be careful tho because it can catch fire especially if it has leaky ignition parts. so keep fire blanket or extinguisher handy just in case. Also if you mess with throttle body taking sensors out, you might want to check out this thread and check your installation
forum.ih8mud.com

TPS/APPS problems

forum.ih8mud.com forum.ih8mud.com
 
I cleaned my throttle body on my 4 runner and it took a few days for idle to come back down bc of the carbon build up. That’s with the terminal disconnected too.
 
Mike NXP said:
It shouldn't take much more than 2-3 start cycles to get the engine to idle back normally after the reset. Also it will typically just rev high, not bouncing around like you described. I think you are up against another issue, just not sure what.

You mentioned a possible broken PCV, I think you could just remove it again and give it a shake, Shouldn't it be rattling if it's all clear? Suprised to hear how much gunk was built up in there, I wonder if you broke something loose that is now clogged somewhere? I am not too familiar with our TB's so not much help here.
Click to expand...
I tried to remove the PCV Valve and it’s not budging. Any suggestions on how I can remove it?
 
Lubricate the grommet with silicon spray and gently pull out with pliers. Alternate pulling from each side. A seal puller would be ideal for this.
 
I took out and cleaned the MAF sensor as well. Would it be a bad idea to unplug it and see if the car runs fine without it?
 
Update: My car is idle surging. This happens normally when the IAC valve is broken or is stuck open due to carbon buildup. I must have damaged a valve while cleaning. The problem is, I’ve read that the 100 series does not have an IAC valve. The connector I’m pointing to in the picture is connected directly to the PCV valve with a hose. This connector is sitting on the top of the throttle body then enters a small rectangular chamber directly under it which has a small tunnel that goes into the intake manifold. Is this the IAC valve? Because I cleaned it with a pipe cleaner and removed lots of gunk inside the tunnel, connector, and rectangular chamber. Did me cleaning it result in breaking a valve?
 
I could’ve installed the Throttle position sensor wrong. I unscrewed it and put it back but was unsure on if I put it back right. Are there any resources on how to install it properly?
 
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