Improved Idle & Throttle Response - Clean That Throttle Body (Easy 30 min DIY Maintenance)

[mceagle555]

Decided to clean the throttle body on my 2008 LX570 with 178,000 miles and no history of being done before. Made for improved idle and throttle response when taking off from a stoplight. Easy DIY maintenance we often forget about and takes less than 30 mins.

Parts you’ll need:

- 1 can of throttle body cleaner ( < $10 from any autoparts store)
- 10mm deep well socket & ratchet
- Phillips screwdriver
- Needle nose pliers
- Shop towel

Step by step:

IMPORTANT - Do this on a COLD engine. To do a thorough cleaning, you’ll be removing 2 hoses from the throttle body that contain coolant & will spit hot fluid if it is a warm engine.

1. Loosen clamps holding air intake assembly to air box and throttle body. (2 Red arrows)
2. Set air intake assembly on top of airbox. It will remain connected to a hose in the rear, but there is plenty of slack.
3. Remove electrical connection to throttle body (1 Blue arrow)
4. Remove 4 bolts holding throttle body to engine (4 Green arrows)
5. Use needle nose pliers to remove two coolant hoses going to underside of throttle body (2 Yellow arrows) Be careful removing the first one as a small bit of coolant may seep out. It won’t continuously run. Again, make sure to do this on a COLD engine.
6. Remove throttle body and set on shop towel on workbench.
7. Liberally spray throttle body cleaner a bit at a time, and use clean shop towels to rub off the carbon. Use elbow grease to get it clean. Do not push hard on the butterfly!
8. Once satisfied, reinstall in reverse order.
9. Don’t overtorque the bolts. Recommend using a 1/4” ratchet.

Super easy job and good maintenance.

 

[mikesean76]

I ran about 10 bottles of liquimoly throttle body cleaner. I am interested to pull mine off and see if there is any carbon residue still in there. I did this on my 80 and made for smoother idle. Curious if running high octane makes a difference with build up.

 

[gasman4u]

Thanks for the write up. Is there a gasket that needs replacing if you remove the TB from the engine?

 

[mceagle555]

Thanks for the write up. Is there a gasket that needs replacing if you remove the TB from the engine?

There is a gasket, but from most of the other write-ups I saw, very few replaced it. I did not replace it. Mine looked to be in good condition & still pliable.

 

[skrypj]

I ran about 10 bottles of liquimoly throttle body cleaner. I am interested to pull mine off and see if there is any carbon residue still in there. I did this on my 80 and made for smoother idle. Curious if running high octane makes a difference with build up.

The fuel never touches the TB so it wont matter.

 

[lookinfwd21]

Just did the TB remove and clean on my fairly recently purchased 2014 due to it began running lean, with no record of having ever being done. Upon removaing the TB which was in dire need of a carbon removal service, I was VERY surprised to see basically fresh mud in the throat of the intake manifold just past the TB. the mud was a mix of fuel and very fine silt, likely from a recent Death Valley trip. I cleaned it of course, will do injectors and plugs in the very near future, but my question is, what is everyone doing to tighten up the air intake enough to keep the dust out?

 

[gasman4u]

Just did the TB remove and clean on my fairly recently purchased 2014 due to it began running lean, with no record of having ever being done. Upon removaing the TB which was in dire need of a carbon removal service, I was VERY surprised to see basically fresh mud in the throat of the intake manifold just past the TB. the mud was a mix of fuel and very fine silt, likely from a recent Death Valley trip. I cleaned it of course, will do injectors and plugs in the very near future, but my question is, what is everyone doing to tighten up the air intake enough to keep the dust out?

View attachment 4040713

There's a thread somewhere that recommends using some sort of temporary "form a seal" type epoxy on the "clean" side of your air filter gasket and intake housing. @bloc iirc was the first to recommend this, but I could be mistaken....the name of the product escapes me - white tube and green/black writing I think.

 

[bloc]

There's a thread somewhere that recommends using some sort of temporary "form a seal" type epoxy on the "clean" side of your air filter gasket and intake housing. @bloc iirc was the first to recommend this, but I could be mistaken....the name of the product escapes me - white tube and green/black writing I think.

I use a thick grease designed for the job made by K&N..

As for the TB gasket.. it’s cheap, and includes a new mesh strainer. Given the low cost it’s easier to replace than clean the carbon and gunk from the strainer. So I put a new one in.

 

[gasman4u]

That's something different than I'm using. I'll have to check order history. update to follow...

 

[lookinfwd21]

Thanks gasman4u, thanks *bloc - will look into both. Also a general thanks to the forum contributors - informative value? Priceless...

 

[GrouchyTech]

Wait, y’all aren’t truly removing the coolant hoses from the TB are you? Just remove the 4 bolts and the wire harness, clean things up, pop it back on.

 

[gasman4u]

Wait, y’all aren’t truly removing the coolant hoses from the TB are you? Just remove the 4 bolts and the wire harness, clean things up, pop it back on.

This is exactly how I did mine. In place. Slowly and deliberately. It took some time for sure. No coolant hoses removed.

I didn’t want to poke the bear with respect to potential coolant hose fitting leaks, etc.

 

[gasman4u]

Thanks gasman4u, thanks *bloc - will look into both. Also a general thanks to the forum contributors - informative value? Priceless...

Happy to help. This is the stuff. I can’t remember who recommended it, but it wasn’t my idea initially. I too benefit from the mud hive-mind.

 

[RangerPepe]

That is oddly large amount of crap in the TB pipe. I cleaned my TB at 60k miles and the was virtually 0 build up of any kind. A little smidges of fine black dust hardly noticeable on paper towels.

There was a myth about original filter box not properly sealing the air filter or something, but I never found this one to be true. Could be the case of K&N filter oil and dust sipping in the intake or perhaps PCV valve stuck open or failed oil separator?

 

[lookinfwd21]

I'm looking into those two things. What makes it tough is I can turn a wrench but I'm not a mechainc and don't fully understand how this stuff works. Was talking to a mechanic who suggested the buildup of grime was from dirt in the oil via blowback, something to do with the PVC valve? I've been taken to the cleaners before, now I'm retired and have time to figure this stuff out but have a healthy distrust of dealers. I'll get there....

 

[GrouchyTech]

I consistently see air box lids that aren’t fitted correctly and the rubber filter gasket/surround gets deformed.

 

[bloc]

There was a myth about original filter box not properly sealing the air filter or something, but I never found this one to be true. Could be the case of K&N filter oil and dust sipping in the intake or perhaps PCV valve stuck open or failed oil separator?

Not a myth.. it’s a well-known issue on turbo-diesel models that have a different airbox (leading to relatively common piston ring wear) and seems to impact some 5.7US rigs as well. Mine was one. Even after cleaning the upper airbox, replacing the Genuine Toyota filter with a new one of the same type, I got a very small amount of extremely fine dust inside the clean section of the airbox.

The filter grease I mentioned above stopped the dusting issue.

 

[RangerPepe]

Not a myth.. it’s a well-known issue on turbo-diesel models that have a different airbox (leading to relatively common piston ring wear) and seems to impact some 5.7US rigs as well. Mine was one. Even after cleaning the upper airbox, replacing the Genuine Toyota filter with a new one of the same type, I got a very small amount of extremely fine dust inside the clean section of the airbox.

The filter grease I mentioned above stopped the dusting issue.

Hmm .. didn't think of turbo-diesels with higher intake pressures. But honestly surprised, gas version air box seems to be really sturdy with balanced clamping springs at all 4 corners, it always feels like it is crushing filter edge gasket quite nicely against the intake half.

That made me take and inspect mine, to my surprise it has an extra filter inside (LX570), does LC have a different box? Because I am quite sure my friends LC didn't have this one.

 

[bloc]

Hmm .. didn't think of turbo-diesels with higher intake pressures. But honestly surprised, gas version air box seems to be really sturdy with balanced clamping springs at all 4 corners, it always feels like it is crushing filter edge gasket quite nicely against the intake half.

That made me take and inspect mine, to my surprise it has an extra filter inside (LX570), does LC have a different box? Because I am quite sure my friends LC didn't have this one.

View attachment 4042622

LC has the same thing. Forum consensus seems to be that it is a carbon filter to trap VOCs drifting out the intake after engine shutdown. And for the record it is much less brown on new vehicles than in your picture.

Yes the box seems well designed but with the prevalence of the issue in the turbodiesel models and my experience (and others on this forum) something is amiss. My assumption was that the box didn’t have a thick enough edge to avoid deflection when clamped, given the length of all four sides of the filter.

Others don’t seem to have the dusting issue.. I haven’t looked into whether there was an update, correlation with certain years, or maybe it’s climate related like maybe being more common in warmer areas. I just know for some of us it isn’t a myth, or incorrect install.

 

[stonepa]

Yes the box seems well designed but with the prevalence of the issue in the turbodiesel models and my experience (and others on this forum) something is amiss. My assumption was that the box didn’t have a thick enough edge to avoid deflection when clamped, given the length of all four sides of the filter.

Others don’t seem to have the dusting issue.. I haven’t looked into whether there was an update, correlation with certain years, or maybe it’s climate related like maybe being more common in warmer areas. I just know for some of us it isn’t a myth, or incorrect install.

My 200 has spent a huge amount of time on gravel / dirt / sand / dust roads. I have never had anything in the air box or intake. So probably occurs but there is some evidence it is not common. But make sure the air box is closed up correctly.