Cleaning Throttle Body W/trac - # Of Sensors To Disconnect?

prix · February 14, 2012

Ok, using the lexls.com tutorial along with a one sheet (pdf) that describes (no photos) how to clean the Throttle Body on a '94 LS400. I thought I was clear on everything, then noticed the lexls.com tutorial gives instructions for a Throttle Body with NO Traction Control, which is what I have. I have a Throttle Body w/TRAC.

So how many connectors do I need to disconnect from the TB w/TRAC? The pdf mentions disconnecting a throttle position sensor connector, and two sub-assemblies (sub-throttle position sensor connector and sub-throttle actuator connector). Can someone please verify that there are THREE connectors on a TB w/TRAC to disconnect?

Also, is there any way this can be screwed up? Is there some trick to putting the sensors back on? I ask, because the cost of a new TB w/TRAC is $1,300 (and change). I already know about using only Throttle Body Cleaner (will use CRC brand).

Also, on another thread, someone said they disconnected the MAF (another very expensive part). Is that necessary when cleaning the TB? If memory serves, I didn't see anything in the lexls.com tutorial about disconnecting the MAF. I don't want to go near that unless it's required.

Thank you!

steve2006 · February 16, 2012

The TRAC models have 2 throttle position sensors so there will be only one extra plug to disconnect and inside the throttle body there are 2 butterfly throttle plates the outer one is the normal throttle and will be closed, if you open this one you will see the sub throttle for the TRAC which will be fully open.

Dependant on how bad the build up is you may be able to clean it without removal from the car using carb cleaner a tooth brush and some lint free cloth but a more thorough job will need it to be removed.

You can disconnect the concertina section of the intake at the MAF and then the other end onto the throttle body so you don't need to remove the MAF.

Yours should look like this

prix · February 17, 2012

Thanks for the detail. This looks do-able, as long as it's done methodically. I'd rather take the TB out and do a complete cleaning, as well as keep the spray away from any other parts.

billydpowell · February 17, 2012

this might help:

Throttle_body_components1.pdf

steve2006 · February 17, 2012

this might help:

Cheers Billy although that is for the later VVTI engine.

If you are removing the throttle body get yourself a new gasket for the TB to plenum chamber.

Leave the throttle pots attached to the throttle body once you have disconnected the plugs to them as they would need realigning if removed and refitted just try and avoid any cleaning fluid getting near them.

One of the hardest parts is removing the water hose under the TB it's a bit tight in there but take your time, refer to your tutorial and you'll be OK.

prix · February 18, 2012

Yes, a new gasket from Lexus is on its way. I'm also replacing the pcv valve and grommet.

Re the throttle pots..on another thread...someone took the pots (sensors) off and the car ran horribly after. It was resolved when they realigned them, as you say. If there's a way to 100% protect them from the cleaner spray, I am fine with leaving them on!! Tx for the suggestion!

this might help:

Cheers Billy although that is for the later VVTI engine.

If you are removing the throttle body get yourself a new gasket for the TB to plenum chamber.

Leave the throttle pots attached to the throttle body once you have disconnected the plugs to them as they would need realigning if removed and refitted just try and avoid any cleaning fluid getting near them.

One of the hardest parts is removing the water hose under the TB it's a bit tight in there but take your time, refer to your tutorial and you'll be OK.