High rpms cleaning throttle body

[Shane_H]

So I cleaned my throttle body and now my RPM won't go lower then 2000 at idle, any idea how I can fix it?

[johnnyjohnny]

Make sure the butterfly valve is closing completely...sound like it's sticking open a bit. Maybe there's something jammed in the mouth or pivots (sometimes when you're cleaning, some crud can get dislodged), the spring is binding on something, etc. How did you clean the TB - on the manifold, completely removed it, dissassembled it?

[DarkCaporaL]

Are the throttle bodies the same as on the RB26?

The throttle bodies are covered in a thin rubber coating to help seal them. If you removed it when you cleaned them it would explain the high idle and you will have to reseal them.

[nelsonmxmarc]

If you removed the TB from the plenum, it's likely you now have a leak where the gasket is. They're very finicky and it's likely it tore or is no longer sealing properly. Another issue with cleaning the TB is the TPS adjustment afterwards. If you havent properly adjusted the TPS voltage, you'll likely see a gain in rev's.

[Shane_H]

How do I go by setting the voltage, I never really figured out how to idle re learn on a rb20

[nelsonmxmarc]

Idle relearn will be a process through which the ECU calibrates the AACV based on inlet air amounts, so basically when you adjust the small set screw on the AACV body.

TPS is somewhat different.. TPS is the small black box on the side of the throttle body (which led me to believe you readjusted it slightly).

To adjust the voltage; Put the ignition to ACC (the one before cranking over) grab the wiring loom where the small gray rectangular connector is and probe the center wire (White). Take your other lead off your volt meter and ground it (Jam it in the negative battery ground terminal because you'll need both hands). Once a small enough incision is made on the white wire you'll be able to record a solid voltage number - you'll be looking for approximately .48 volts. Anywhere from .47 to .50 is good. To achieve a change in voltage, loosen one of the small bolts on the TPS (top and bottom) and tilt it from side to side. This will insure the TPS is no longer contacting at idle, creating an irregular idle value..

[Shane_H]

So the voltmeter will adjust the voltage in the TPS? Just trying to understand this clearly so I learn something from my stupid mistake lol, how does the volt meter fix the tps exactly?

[Shane_H]

Ohhh the bottom bolt on the tps snapped so now only the top bolt is holding it there, could that be my problem?

[nelsonmxmarc]

haha all good buddy!

TPS voltage measurements are changed in increments of how much contact is made between the pin on inside and the throttle body plate.

bolt on the tps snapped so now only the top bolt is holding it there, could that be my problem?

Absolutely. Those bolts are a REAL PITA. Same thing happened to me, TPS went bonkers. If you take a reading with the volt meter tapped in and wiggle it even the SLIGHTEST bit, you'll see how much the voltage fluctuates.

Put a new bolt (make sure the head fits snug and tighens it down, the thread hole isnt very long), I'm not sure how long they are exactly, but i had to cut a bolt to fit.

Once that's done, adjust to the correct voltage and you should be good to go.

[Shane_H]

I snapped the head of the bolt off in the throttle body now can get the rest of the bold out

[Shane_H]

How should I go by removing the broken bolt from the throttle body now lol

[nelsonmxmarc]

Easy-out .. or drill.

What i did was use my dremmel to dremmel a small notch in the screw that was jammed in place, just wide enough to get a small screw driver in there to turn it out.. lol Worked out pretty well..

[Shane_H]

I'll give both methods a shot and update with results lol

[Shane_H]

UPDATE! so I went with my gut and followed your instructions so I got the dremil tool out and went to work, 10min later I had the ever elusive broken screw OUT! (thank god) I then spliced into the white wire on my TPS and got to work with the multiple meter checked out my situation and BAM .7 volts!!! I then adjusted my TPS count clock wise till it read .4 volts tightened the screws, unplugged my battery to reset the ecu, pressed the break 5 times to get the rest of the power left in the car, pointed my wheels straight so I didn't mess up the HICAS. Finnishing the steps I plugged the battery back up, switched the key to the ON and OFF in the ignition 5 times so the TPS could re learn the volts. Finally I start the car and it idles like a dream!!!

Special thanks to nelsonmxmarc for very accurate and straight forward instructions! Problem solved =D

[Skym]

Good to hear you fixed the problem.

TPS doesn't relearn, would be just clearing TPS error code if any on ECU. The TPS settings are permanent on ECU unless you adjust via laptop, tuning software. It's alot easier via laptop, tuning software, as the idle contact button light's up on laptop. Usually when TPS is old, best to replace, as idle, WOT contact pins bend, etc.