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Cleaning throttle body

Old Sep 22, 2008, 12:38 PM
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Cleaning throttle body

This was on a car with only 17,420mi. So I would recommend this maintenance every 15k or so.

The problem I was having was at very light throttle (parking lots, on and off city driving). It felt like the throttle was sticking slightly after it was in the closed position. I didn't know if it was the cable or the plate.

After operating the plate manually from the engine bay, I confirmed it was the plate that was sticking. So I removed the UICP to get a visual on the plate. Holding it WOT, I could see that there was major carbon buildup on the back side and around where the plate seals (not uncommon).

You already removed the UICP for visual inspection.
Remove 2 vacuum lines on top of the TB
Remove TPS connector.
Remove ISC connector.
Remove 4 TB bolts (12mm head).
Remove throttle cable.
Remove throttle cable from the routing clip on the valve cover (makes it easier to get the TB out later).
At this point I then removed the TB coolant lines. I found them much easier to remove w/ the TB unbolted. A little coolant spills out of them, so make sure to have something ready to plug them off. I used two sharpie markers (it was the only thing available that worked at the time). I bought a pack of plastic plugs that work perfect after the fact, if anybody needs some let me know.

At this point you should be able to remove the TB for cleaning.

Cleaning the TB:
First I tried carb cleaner from Advance Auto Parts. After spraying the back of the plate and scrubbing with a tooth brush for 2 or so min, no progress was made.
I ended up finding a can of Honda carb cleaner in my tool box. One squirt and the carbon flew right off. I didn't even have to use the brush yet. One thing I noticed, The Honda cleaner smelled like lacquer thinner, the Advance stuff smelled like kerosene. This may be why the Honda carb cleaner worked so well. Moving on.
Spray and scrub the back of the TP, sealing surface, plate shaft and don't forget the ISC valve passage. I was surprised at the amount of crud that came out
of there.
I found the Advance Auto carb cleaner spray good for the final rinse, as it left a oily residue that might help protect the aluminum and lube the plate shaft, So it was still useful. Iduno, just a thought.
Wipe TB down with clean paper towels.

Assembly: Reverse of removal w/ the exception of the coolant lines. I found them easier to connect after the TB was installed with the bolts finger tight.

After you connect and coolant lines and position the clamps properly, give them a good tug as if you were trying to pull them back off. This helps prevent a leak by butting the clamped section up against the beaded tube.

Before starting the car, it would be a good idea to spray down the work area with a hose to remove any coolant that may have spilled.

After my car was warmed up, I had to turn the idle down as it was idling at 1,200-1,500rmp. Which didn't surprise me since the ISC passage and plunger was so dirty. The carbon build up was actually blocking part of the passage which required me to turn the idle up every now and then over the past few years.

First test drive:
Throttle operation is smooth as can be. No more sticking when I touch the throttle, feels like the day I drove it home for the first time.
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Old Feb 7, 2010, 10:23 PM
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