Throttle Body Cleaning, worth the hassel?

TB deposits are not particular to the Northstar. ANY TB will get carbon deposits on it. Fuel is delivered at the intake ports as opposed to the TB like on a carburator, so there is no fuel spray to wash it off. PCV gasses are drawn into the intake manifold and burned, but when you shut down, the gasses remain in the intake and condense on the TB which cools first. Remove the intake ducting and the MAF sensor. You will see that WOT does nothing to clean the TB. I think it is recommended service to clean it every 30K or so. Personally, I like to do it every spring. You will need to do more than just spray it though. Use an old toothbrush and scrub it loose and wipe it off with a rag. Pay particular attention to the TB bore where the throttle plate meets the bore. Don't forget the throttle plate perimeter and backside.

NoCadiYet said:

'01 Deville, and I am NOT mechanically blessed and having NO special tools of any sort, am I best to Let Cadillac do this for the $235.? 51K miles, and getting about 22 MPG(mostly HWy) hoping to increase performance and MPG. With no probs to speak of, is this Service something for me?

Thanks!

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NoCadiYet, don't waste your time or money having a dealership do it. All you need is a screwdriver to loosen the intake hose clamp so it can be pulled off the MAF and a socket (10mm?) to remove the three bolts that hold the MAF on the throttle body. That's it for tools. Then, with the throttle body bore and blade exposed, you just need a rag (I like also using an old toothbrush) and some carb cleaner from any auto parts store. Push the blade open and spray some carb cleaner on the back side of the blade and around the throttle body opening. Wipe it clean with the rag, including the edges of the blade. Do this a few times until the edges of the blade and the areas around where the blade touches the bore are clean. When you're done, put it back together and disconnect the battery for 60 seconds to clear out any learned idle values and let it figure out the idle again now that the TB is clean. It literally takes 10 minutes or less even if you do a really thorough job. Paying $235 for it is insanity. By removing the deposits around the perimeter of the throttle blade and bore, you're clearing away the built-up gunk from the PCV system (oil vapors and such) that accumulate in that area and cause the throttle blade to stick in the closed position sometimes. It might help smooth out the idle a little bit, and it could especially help on a 1995 or older N* that uses the Idle Speed Control motor to adjust idle. It doesn't help quite as much on an IAC (96 or newer) car, but it takes the stickiness out of the pedal for my 96 SLS and prevents jerky starts in parking lots and such. I think it's a good idea to do it and it doesn't take long at all. Please don't give your money to a dealership to do this.

I did it on my 1995. Was caked about an inch 1/2 deep with deposits. Took me over an hour and 3 re-applications to clean that SOB out. I know i spilled a lot of the gunk down there too, so i changed my oil filter at the same time just to make sure none of that garbage gets stuck in the engine and wears away the bearings.

It cleared up the sticky pedal a lot and it seemed smoother idling (mine uses idle control motor on the 4.0). But it could have been just speculation as when i bought a new EGR, it idled a whole lot better than before even.

Every once in a while before i fixed these 2 items, it would idle as high as 2000rpm and then back to 1000, then up to nearly 2 grand again. I hated putting it into gear then, as it would be just like neutral bombing it, so i had to wait like 25 minuets one time in the summer for it to stop doing that crap and put it into reverse.

The 3 screws that hold the MAF on the throttle body are 7mm head screws.
Don't drop them....

Try a delco distributor or go to your local GM parts house (any division will do) and get a can of aerosol "Top Engine Clean".
That stuff will make your throttle body so happy it will blow your mind.
Spray a little on, let it soak, then spray some on a rag and wipe it off.
Hold the throttle open with your fingers and do the same on the back of the throttle plate and in the bore. Latex gloves are a good idea as the TEC might irritate your skin a bit.

If you are a bit squeemish, I can do it for you. Actually the stuff we use works pretty good at cleaning out the inside of the intake and the runners too. I don't know what we charge for it but it really helps.
I usually do a bit of extra cleaning on the Throttle body after the "induction service" that we do.

You can run the engine with the MAF off and spray the TEC in the IAC passage. It gets dirty too and can make the IAC a bit sticky in the bore at times.
The cans are big, don't spray it too fast, and you might have to take it out and give it the gas a bit, sometimes it will make the car smoke pretty good out the tailpipe for a few minutes. Your neighbors might call the fire department if you do it in the driveway.