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I am chasing down a small hickup in my 02 tt X50. In checking out all the vacuum lines I pulled the throttle body off. It does not close fully. Kind of spring loaded open just a touch. If I press on it the plate edge moves about 1/8" and closes. I let go and it springs back. Is this normal? I think so because there is no stop screw. If somebody has their TB exposed can you push on it and see if this is normal?
I cleaned it, even took it apart to see if something was binding. Looks like it is ether designed this way or something has slipped position on the shaft. All the gears and motor drive look fine, no wear that I could see.
I cleaned it, even took it apart to see if something was binding. Looks like it is ether designed this way or something has slipped position on the shaft. All the gears and motor drive look fine, no wear that I could see.
The butterfly valve won't close all the way. And it won't fully open, that is go to the point it is parallel with the TB's center line.
The TB is controlled/monitored by a sophisticated electro-mechanical system, a safety critical system. If this system reports no problems, if there are no active, pending error codes the system is fine.
The TB should not need cleaning. If it is dirty this is a sign of an incorrectly functioning air intake/air filtration system, possibly arising from an aftermarket system having been fitted. If the TB is dirty/oily this then can be from possibly leaking turbo seals, an engine overfilled with oil, or an engine that is manifesting excessive blow-by.
For both of my cars with healthy engines, I have never had to clean the TB (or the MAF), with one exception: The one time I found the TB dirty (oily) on my Boxster was due to a failing AOS. The Boxster TB was cleaned at around 80K miles and has not been cleaned since with now over 210K miles of driving. At 139K miles my Turbo's TB has never been cleaned.
I am thinking that it is fine. Someone else posted about a cobb tune install and that it got rid of a partial throttle hickup. I am starting to lean towards the conclusion that there is nothing wrong with my mechanicals and that I may have less than optimum tune.
I am thinking that it is fine. Someone else posted about a cobb tune install and that it got rid of a partial throttle hickup. I am starting to lean towards the conclusion that there is nothing wrong with my mechanicals and that I may have less than optimum tune.
To say a throttle body never needs cleaning is just dead wrong. In fact na 996 need to be cleaned ocassionaly. Combustion gases do find their way into the intake system causing deposites to be left behind. It has nothing to do with the intake filter, if maintained properly. Since these are drive by wire, the actual servo motor may be not allow it to close.
Yes I have done the egas reset, checked for boost leaks, fixed the major leak that was the fuel pressure regulator vacuum line that was disconnected, checked for vacuum leaks, cleaned the throttle body, cleaned the MAF, replaced the MAF, logged a bunch of parameters using durameteric. None of this made much difference or has she'd any light on the cause.
To say a throttle body never needs cleaning is just dead wrong. In fact na 996 need to be cleaned ocassionaly. Combustion gases do find their way into the intake system causing deposites to be left behind. It has nothing to do with the intake filter, if maintained properly. Since these are drive by wire, the actual servo motor may be not allow it to close.
There is no scheduled TB (or MAF) cleaning. AFAIK no dealer has even come up with a TB cleaning add on service procedure to fatten its already obese bottom line.
Any TB cleaning is a solution in need of a problem.
As I mentioned in my earlier post the TB was dirty (oily) when what proved to be my Boxster's first AOS failure. I cleaned the TB but the symptoms came right back. The AOS finally got so bad as to route oil through the engine to the point the engine hydrolocked -- this at the dealer.
The TB was not cleaned then. The engine was fine after the AOS was replaced.
The AOS has failed two more times. Both times the engine ended up smoking like a coal fired Chinese power station. Just the AOS was replaced and the TB (and MAF) were left untouched.
The engine was fine.
The TB is inherently self cleaning unless the air intake system is so badly compromised as to let in dirt or in there is something seriously wrong with the engine. Then a dirty TB is the least of one's worries.
There is no scheduled TB (or MAF) cleaning. AFAIK no dealer has even come up with a TB cleaning add on service procedure to fatten its already obese bottom line.
Any TB cleaning is a solution in need of a problem.
As I mentioned in my earlier post the TB was dirty (oily) when what proved to be my Boxster's first AOS failure. I cleaned the TB but the symptoms came right back. The AOS finally got so bad as to route oil through the engine to the point the engine hydrolocked -- this at the dealer.
The TB was not cleaned then. The engine was fine after the AOS was replaced.
The AOS has failed two more times. Both times the engine ended up smoking like a coal fired Chinese power station. Just the AOS was replaced and the TB (and MAF) were left untouched.
The engine was fine.
The TB is inherently self cleaning unless the air intake system is so badly compromised as to let in dirt or in there is something seriously wrong with the engine. Then a dirty TB is the least of one's worries.
All cars even properly functioning ones can benefit from a TB cleaning if its dirty. To say that a properly working 996TT throttle body doesn't get dirty is like about the funniest thing I have ever heard in my life. To say that dirt can't cause problems is also equally laughable. You clearly have not seen idle surge from a dirty throttle body or on older cars a poor cold idle.
The 996TT is a turbocharged motor which means that the intake tract is always dirty. Which is why DI Turbo engines across the board have serious problems with carbon buildup on the valves.
Its always worth a try to do the simple things first.
P.S. Electronic Throttle Bodies without signal generally sit slightly open for good startup characteristics.
All cars even properly functioning ones can benefit from a TB cleaning if its dirty. To say that a properly working 996TT throttle body doesn't get dirty is like about the funniest thing I have ever heard in my life. To say that dirt can't cause problems is also equally laughable. You clearly have not seen idle surge from a dirty throttle body or on older cars a poor cold idle.
The 996TT is a turbocharged motor which means that the intake tract is always dirty. Which is why DI Turbo engines across the board have serious problems with carbon buildup on the valves.
Its always worth a try to do the simple things first.
P.S. Electronic Throttle Bodies without signal generally sit slightly open for good startup characteristics.
The intake track prior to the turbos is relatively clean. However the turbochargers themselves always leak a small amount of oil from the center bearing. They always seem to be improving on this but it's still not perfect. Lots of older cars have small holes even to drain this intake oil from the intercoolers.
11-26-2015, 08:08 PM
Throttle body question
