StanVanDam

Note that when you clean your throttle body, DO NOT move the flap by hand. This is why some people need to reset the ECU or have other problems. The throttle in the LS430 is drive-by-wire, meaning the flap is operated via a motor (not a cable) via the ECU, and the position of the flap is sensed via a precisely calibrated throttle position sensor. Moving the flap by hand can throw off the calibration and/or apply too much force to the throttle control motor or extend the flap beyond its normal range, which could damage the motor or cause the flap to not return to where the ECU expects it to.

The proper way to open the throttle body flap is to have someone press on the accelerator while the ignition is in the ON position. This is how the car naturally moves the flap, and there is no risk of throttle body control motor damage or throwing off the calibration of the throttle position sensor.

If you have an incorrect idle speed, it is quite possible (maybe even likely) that your throttle position sensor has become miscalibrated.

yelloa3gti

SUCESSFUL MAF CLEANING

I recently purchased my LS430 (2003 with 118k miles) before even driving it I noticed it hesitated a little when reving it in neutral. The car idled smoothly and quietly. There was no CEL. As soon as I drove it the car fell on its face with anything over 1/3-1/2 throttle. The car would backfire sputter and wouldn't shift correctly. I quickly diag'd it as MAF related. I unplugged the MAF and it reved smoothly but wouldnt go over 3k rpm and kicked the CEL. I talked to my buddy at the Toyota dealer and he said to attempt to clean it before I buy a new one. $9 in parts (CRC cleaner) and about 30 mins the problem is fixed. Has been flawless for the past 700 miles. Quick easy DIY fix!

There was a good VID on youtube I followed.

PS- use a ton of cleaner, I used a whole can!

MarcS

And we're back to 350-400 rpm idle speeds. I wish I knew about not opening the valve by hand as that's what I did. Granted, I was having idle speed issues before, so I don't think I made it any worse. Is there a way to recalibrate the throttle position sensor?

Toad05

See the figure below for an additional place to clean inside where the TB bolts to the engine.

jdanielca

Where can i find a similar diagram for the 4th gen 2007 , I've been trying to figure out some stuff is the gasket metal? For the TB itself I did not notice a gasket when I open it up

HLamar

You can use any sealant such as Toyota sealant, Threebond, Yamabond or other type sealant in substitution of a gasket in your situation such as this without problems. Just small coat where gasket sealed. Don’t smear so that it can drop into TB when dry.

Yamae

It is also very important to clean those 2 air passages that are are connected to 8 injectors indicated by red arrows below. You almost need to use a full can of carbon cleaner with an air compressor to perform this. Sometimes 2 cans are needed. Spray the cleaner and then apply the compressed air to those 2 holes and repeat this until the engine runs smoothly. The purpose is to clean air mix passages from those holes to injector ends. This has fixed many 98-00 Celsior, LS400 and LS430 that still had rough idle problems even after the throttle body was cleaned. I also have to add that this has to be done while the engine is idling. Otherwise you'd have very hard time starting the engine if done while the engine was stopped due to the too much carbon cleaner remaining in the cylinder.

HLamar

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ChopsGS

Yes, an old post, but also not correct. It has nothing to do with moving the TB blade by hand.

The reason for the high idle after cleaning is due to the ECU adjusting the TB over time to compensate for loss of air at idle as the idle air ports clog with carbon. Over time, the "default" idle position for the TB blade is greater than when new and/or clean. Once you clean the TB and those idle air ports are opened back up to original size, there's now more air coming into the TB which is still adjusted to the greater opening angle.

Soft rebooting the ECU via battery disconnect, or via the OBD2 port/scan tool, or cycling the engine on and off an X number of times, or driving the vehicle for an X number of miles will reset the TB position back to the proper angle which will naturally result in a normal idle RPM.

I had to do the same when I bored/polished the dual TB's on my 370Z, as well as cleaning the TB's on my friends Golf R, NC Miata, C6 Corvette and E60 M5 BMW. Pretty much any vehicle with driver-by-wire TB's will require this sort of reset after a good cleaning (or in my particular situation, boring/polishing).

kos

iTrader: (1)

Excellent writeup on this thread.

911LE

Except that the OP doesn't show how to clean the MAF. His procedure only cleans the IAT, the intake air temp sensor. The MAF sensing wires are inside the black tube on the same part. It's 2 sensors in one.

911LE

Here are the wires that need to be cleaned.

The 2 silver wires running right to left. It looks like one has a resistor built in.

ChopsGS

This one as well... Mine was caked with black crud.

kos

iTrader: (1)

Interesting. Never have cleaned those on any of my cars that utilized a MAF like that, just the "bulb" end.

There's a poorly focused photo in step 3 of the original post that alludes to this.

StanVanDam

Agree that the ECU adjusts and memorizes idle (within a small range), and your explanation of high idle is correct for most situations after a recent MAF/TB/idle port cleaning. However, your explanation does not address low idle, or the fact that the LS430's throttle position sensor has a physical calibration procedure per the attached picture.

After a cleaning, you should do a 10 minute battery pull (my copy of Techstream and/or my cable cannot clear my Canadian 2002's ECM/PCM memory/learned values, but a battery pull is guaranteed to work), followed by 5 minutes of idling in the driveway, followed by a 20 minute drive in-town. If your idle is still incorrect and your idle ports are clean, throttle plate is clean, and there is no cleaner residue/vapors in the MAF or inside your throttle body, you probably knocked your TPS out of calibration, damaged the throttle position motor, and/or damaged the MAF during cleaning.