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Dirty Throttle Body

XRover

Charter Member
SM 2003
Full Member
Joined
Jan 26, 2002
Messages
1,610
Location
Los Angeles, California
I have been having rough idle problems for some time. Since I have a FIPK and TB Spacer and the computer is not throwing out any codes, The dealer blames the intake mods.

I decided to pull off the TB and spacer and check them out and see if I was possibly getting any leaks. I found black grime in the back of the Throttle body bore and the TB spacer as well ass the sensor which is located above the throttle position sensor. I am wonder where all this black grime is coming from. Making it's way through the Airaid Filter ?

The grime is a fine black soot. I removed the sensor and carefully cleaned it as well as cleaning the TB and the Spacer. I reinstalled everything making sure that the Spacer was perfectly seated against the intake manifolds blue seal. I noticed that the TB spacer does have a bit play and if not held up when tightening, it might not make a perfect seal on the blue seal.

I guess now it is a wait and see if the idle is any better.

Anybody else look at their TB after running a FIPK and TB Spacer. Any Grime ?
 
I am concerned !!!

Where did all that stuff come from and what is it doing to the engine.

I swabbed the inside of the Air filter and it was clean. I swabbed the inside of the intake tube and that was clean. Maybe the TB spacer was not creating a perfect seal ??

It is now !!
 
It sounds like you may have had a seal problem. If the filter is clean, and the intake tube is clean, it must be past that point. It kind of points to what you said, the seal between the spacer, and the t body. I have the FIPK, but not the spacer, and have not had that problem. Now that you resealed the system, its just a wait and see. Did the rough idle go away after you resealed the spacer?
 
hope that this fixes the problem, sounds like you were drawing from the TB, this would screw up the MAF in addition to the crap you were pulling in - very dangerous. By all means check the idle and TB for dirt on a very regular basis for the next week.

To the rest, use this as a wakeup call, check tomorrow. ;D
 
So far today the idle has improved but now that I said that I am sure tomorrow the engine will blow up :eek:

I will need to put some miles on it and see if there is a permanent improvement. Mothers Day. Mom lives 70 miles away. Going to see mom......
 
XRover said:
So far today the idle has improved but now that I said that I am sure tomorrow the engine will blow up :eek:

I will need to put some miles on it and see if there is a permanent improvement. Mothers Day. Mom lives 70 miles away. Going to see mom......

There is a good possibility that the leak was bypassing the MAF and confusing it - faked it into thinking the thing was starved - you may want to run a couple of tanks with cleaner through it.
 
How many miles do you have on the av?
I had checked with dealer when i bought the av to see if they had cleared up the tapping or as some say piston slapping noise at start up and the sticking throttle.
My 2000 Z and my 2001 yukon both had the 5.3 and at about 25000 miles roughly the throttle starting sticking when you went to take off you could feel it. Felt like it was stuck and it would pop free. they would do a clean up on the throttle body. ???What can build up in that section?? They told me that the tolerances were to tight and then they installed a new throttle body on each vehicle... but they did say they were getting a carbon build up,, don't see how that is possible in that spot. any way after they changed throttle bodies it was ok
He said i should be ok with the av since they have figured out the problem. But my mechanic still wipes it down when he does my oil changes to make sure it does not build up.???? Hope the fix you did takes care of it, just wanted to add this because it the first time i have seen anything mentioned on here about the build up like i was getting and that was with factory intake with only a K and N replacement filter.
zeeya
 
After reading this thread I went out and looked at my throttle body and spacer. ?I also saw the black "soot". ?Cleaned it off and re-seated the TBS. ?In my case, the "soot " was also in the throttle body in the up-stream throat area. ?Last time I checked, the air only goes one-way through the throttle (unless it back-fires, which mine has not), so a leak in the TBS seal could not have produced the "soot" up-stream from the throttle valve AND the TBS.

A theory. ?The FIPK filters are treated with oil. ?Is it possible that micro-droplets of the oil make their way along the air flow path until they come in contact with the first hot surface they find (ie., the throttle body) where they pyrolyze and leave behind the black "soot". ?If true, the "problem" should lessen over time as the excess oil from the filter is blown through the system. ?Someone with more experience with FIPK apps than me should comment. ?Does this make sense?

One other comment. ?I had been intending to re-seat the TBS anyway, because I had a feeling that the "whistle" ?from the TBS was getting louder, and suspected a leak. ?After re-seating and tightening everything in the air path, it was obvious that I did have a leak. ?The "whistle" is MUCH softer. ?While this may help the rough idle (I have also noticed this), I don't think it is responsible for the black "soot". ?JMHO. ;D ;D

RPH
 
I drove 160 miles today after cleaning up the Throttle Body and spacer and reinstalling them. The idle has improved significantly but what is going to happen next month or after that ? Is it from the K&N Filter ? I have not taken it off road yet and I don't encounter dusty roads.

The point about the whistle being louder from the TB Spacer is right on. Mine was loud. I thought maybe I had a Turbo Charger Hiding in there. After re seating the TB Spacer the loud whistle went away and is barely noticable.
So there was an air leak downstream of the Throttle Body. Now to the issue of the residue. As RPHagan stated, the soot was on both sides of the TB and also in the rifling of the Spacer in my case.

I have heard of minute particles getting past the K&N type filters and screwing engines up but I have no idea if that was a common problem or just a bitter person spreading rumors.


I have 11000 miles on the AV .
 
UPDATE

I just drove it to pick up dinner. It is now Idling worse than it ever has.

I pulled off the FIPK and put the stock airbox back on. I am taking it to the dealer tomorrow for the third time on this issue. Hopefully they will not tell me it is due to the TB Spacer because if they do then I will remove it and drop it off again.

This rough idle problem I have had since I picked the truck up new. Before I did any intake mods. It feels as though one or even two of the cylinders keeps dropping out.
 
zeeya2000 said:
My 2000 Z and my 2001 yukon both had the 5.3 and at about 25000 miles roughly the throttle starting sticking when you went to take off you could feel it. Felt like it was stuck and it would pop free. they would do a clean up on the throttle body. ????What can build up in that section?? They told me that the tolerances were to tight and then they installed a new throttle body on each vehicle... but they did say they were getting a carbon build up,, don't see how that is possible in that spot. ?any way after they changed throttle bodies it was ok

Your Z had a 5.7, and I believe there was a bulletin on the sticking throttle bods. The tolerances were too close and the blade would stick on occasion. The dealerships were told to replace the TBs they had problems with, and not to adjust them.

As far as 'soot' on the back of, and in the intake, that is realtively common. It is not as bad as LT1 days, but still dealers should be well aware of it. Not sure exactly what causes it, but ALL of my recent GMs have had it. The intake on the C5 has to be cleaned every 5000 miles or so. The idle smooths noticeably after cleaning it.
Your dealer should do a 'top engine clean' for you.
I would remove the spacer before bringing it to the dealer.

Ron
 
I am hearing more people talk about the soot being a normal occurence in these Throttle Bodies and having them removed and cleaned a routine service.

To me that is B.S. If I wanted a vehicle that required part of the intake assembly to be removed and cleaned out on frequent occasion, I would have bought another boat.

There has got to be a better solution from G.M.
 
If you suspect the problem is directly linked to the Air filter...then I would probably recommend getting one of those filter socks...this would fight against any misc...crap flying into your intake.....it would at the very least give you some peace of mind until you could narrow down the problem or cure it all together.... :B:
 
I had the same thing happen on my F-150 when I installed the K&N. The fine oil mist that comes into the TB collects dirt and gunk. I had a whistling sound that drove me nuts. They tore off the entire top of my engine looking for it. They replaced the alternator, water pump, fan clutch, air box. Nothing. It was the goop not letting the butterfly close all the way. There was a sticker in there (at least on the Ford) that said not to use chemicals on this area. I did anyway, and the whistling disappeared.

Now my Avalanche has the same crud in the TB.

For the guys out there old enough to remember oil bath air cleaners---remember the throat of the 1 bbl. carb and all the gunk down there? We used to pour or spray Berryman Chem Tool in there with the idle set up to clean it out. Then----lo and behold, they came out with the lifesaving DRY air filter. We were all so excited !!! Dry air filters. Now, we're back to using oily air filters. Everything that goes around, comes around.

Just thoughts.

Trophyman

:)
 
Interesting Trophyman.

After researching this a bit more, I have come to the possible conclusion that the soot is actually coming from the Crankcase breather hose. That whole area in the TB had more soot in it the anywhere else and directly across from that is a sensor. The sensor was covered in it. Now that said, why is the breather hose putting out so much soot and what is that soot doing to the TB and it's operation ?

I can see that if left unchecked for a while, the amount of buildup will cause the throttle plate to begin sticking which I have read on another site is a problem...
 
First to start off with my 2000 Z71 did have a 5.3 in it, in fact i waited for the 2000's because the 99 5.3 engine only advertised 270 hp and my fatherinlaw was a salesman at the dealership and he told me to wait until the 2000's came out because they had did some fine tuning on them and bumped hp up to the 285 hp. which is the same that was in my yukon and now i have in my AV. They did put some 350's in 2000's but were mostly on work trucks like the 3/4 ton while they were waiting on the HD's to come out. ...................................!!!!
Called Service manager today and he said they were still having carbon build up problem on 99 on up 4.8 and 5.3 and that a lot of the people coming in did not have K and N filters, but the regular filter that they install during service. They are still doing clean ups on throttle bodies when a customer complains....
zeeyaaaaaaaaaaaaaa
 
My 99 Silverado had the 5.3 liter with 270 horsepower. I ended up having the throttle body replaced since there was a TSB on it. It was also sticking and full of black carbon. I cleaned it out first, but then had it replaced after I found out about the TSB.
 
Shafman, did your Silverado engine have a FIPK or K&N on it also?

Just want to be know whether or not I need to re-install the stock paper filter.

Jamie
 
Brought the Av in Monday for the rough idle issue and a couple of suspension noises. Today is Wednesday. So far they have spent 2 days on the Suspension I am told and are still not satisfied OR have not found a problem I don't know the real story.

So, I asked the Service writer, What did they find out about the rough idle. He say's "You'll have to return the intake to stock by removing the TB Spacer then we can test it again. I knew I should have done that !!
 
jamie said:
Shafman, did your Silverado engine have a FIPK or K&N on it also?

Just want to be know whether or not I need to re-install the stock paper filter.

Jamie

I just had the K&N air filter, but there was a problem with the Throttle Bodies even with the stock air filter. I never had a chance to compare the new throttle body to the old one, but it had all new sensors on it too.
 
I just read through this thread and wonder if there are any updates? Is this related to the FIPK, Spacer or K&N filter?

Do non mod owners need to perform any routine maintenance or cleaning to prevent future rough idling?

I've got 6500 miles on mine and still can't tell if its running sometimes...its so smooth..I'd like to keep it that way.

Any updates would be appreciated.
 
I am pretty confident that the soot is coming from the Crankcase breather hose. (Upper left side of TB). I haven't had any problems for the last 3000 miles.
 
My 4.3 with CPI, has TONS of soot / carbon in the TB. So much that I can flake it off....

It's never caused any problems for me. Those of you with a rough idle - what if you turn up the idle speed a little?
 
THERE IS NO IDLE SPEED ADJUSTMENT ON THE 5.3. What looks like an idle speed adjustment screw actually varies the voltage from your TPS (Throttle position sensor) DO NOT MESS WITH IT! Moving this screw will change the idle, but it does so by making the computer think the throttle has moved. This is almost guaranteed to cause other problems.
Throttle body cleaning is, or should be, considered routine maintenance. It should not be neccesary to remove the throttle body to get it clean. Just hold the throttle open (with the engine off) and spray some throttle body cleaner (not carburetor cleaner) into the throat. If it is real bad use a lint-free cloth to wipe it out or a toothbrush to break it loose. Some good fuel injector cleaner (like BG-44K) in the tank once in awhile will help also. This is nothing new and will only take you about 10-minutes to do.
 
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