Possible cause of hesitation, low idle, and stalling: TB and butterfly valve needed cleaning...

Stoney · 09-17-2003, 12:46 PM

We had tried everything else to rid the car of a hesitation off idle when not warmed up. Also had a low idle at times, stalling now and then. Spent hundreds of dollars and several service visits, with no improvement. They had cleaned the carbon out of the injectors and engine (needed it anyway), but no help. I even installed a new MAF and diverter valve myself.

Finally, I talked to the foreman or Rector Motors' service department, who suggested cleaning the throttle body and butterfly valve by hand using a good cleaner product. Said Audi didn't have a procedure for it, so they tend not to do it until it becomes a problem.

When I raised this with our regular service advisor at Anderson-Behel, he said "yeah, I used to need to do that all the time on my xxx car." I didn't say -- but was thinking -- "why didn't you think of this instead of charging us $700 for other procedures that didn't fix the problem?"

I'd have cleaned it myself... its easy... but the car had been flatbedded in the very same day for a broken belt and stuck belt pully. Warranty Direct covered that, fortunately.

RAD69 · 09-17-2003, 12:56 PM

Do these guys even check???

Engine, Fluctuating Idle or Idle Speed Too Low

Yippers® · 09-17-2003, 01:15 PM

cleaning the TB by hand to resolve those symptoms and advising it for a LONG time.

Chard · 09-17-2003, 01:38 PM

what's it dirty from? I remember removing the hose that connects it to the top of the intercooler and seeing oil in there...

Yippers® · 09-17-2003, 02:49 PM

idle etc .. it is throttle body

It gets grimey from the oil vapors drawn in via the PCV system. The really small crude that comes in with the air that passes thru the air filter also contributes.

Chard · 09-18-2003, 08:10 AM

Yippers® · 09-18-2003, 08:25 AM

IIRC it was like 50 cents or less. Disconnect the SMIC to TB hose, unplug the TB sensor wire, pull the cable (on the nDBW) and remove the TB. Once you have it pulled use a good, I like CRC brand, throttle body cleaner to clean the outside and the inside thouroughly. Use a q tip or similar to clean the area around the throttle plate and the plate itself. Pay particular attention to the edges of the plate and the area of the body the plate seats against when closed to the idle position. Do NOT use a carb cleaner as many of these have chemicals that can raise hell with coatings and plastics oft found on throttle bodies.
Once you have everything spotless reassemble using the new gasket and do a TBA before starting.

Stoney · 09-20-2003, 10:54 PM

Stoney · 09-20-2003, 10:55 PM

Stoney · 09-20-2003, 10:57 PM

09-17-2003, 12:46 PM	#1
Stoney AudiWorld Super User Account #: 230 Join Date: Mar 2000 Posts: 5,267	Possible cause of hesitation, low idle, and stalling: TB and butterfly valve needed cleaning... We had tried everything else to rid the car of a hesitation off idle when not warmed up. Also had a low idle at times, stalling now and then. Spent hundreds of dollars and several service visits, with no improvement. They had cleaned the carbon out of the injectors and engine (needed it anyway), but no help. I even installed a new MAF and diverter valve myself. Finally, I talked to the foreman or Rector Motors' service department, who suggested cleaning the throttle body and butterfly valve by hand using a good cleaner product. Said Audi didn't have a procedure for it, so they tend not to do it until it becomes a problem. When I raised this with our regular service advisor at Anderson-Behel, he said "yeah, I used to need to do that all the time on my xxx car." I didn't say -- but was thinking -- "why didn't you think of this instead of charging us $700 for other procedures that didn't fix the problem?" I'd have cleaned it myself... its easy... but the car had been flatbedded in the very same day for a broken belt and stuck belt pully. Warranty Direct covered that, fortunately. __________________ A6 (C5 platform) FAQ Stoney's Picture Library Email: jds@sonolithics.RemoveThisPart.com 2001 A6 4.2L, Sport, Premium, Nemo Blue, Melange Interior

09-17-2003, 12:56 PM	#2
RAD69 Member Account #: 24886 Join Date: Sep 2001 Posts: 3,015	Check this out - TSB on a rough or low idle Do these guys even check??? Engine, Fluctuating Idle or Idle Speed Too Low __________________ Gone but not forgotten - 1998.5 ASS4

09-17-2003, 01:15 PM	#3
Yippers® Member Account #: 19399 Join Date: May 2001 Posts: 17,328	Should tell the dealer to do a search here. I (as well as a bunch of other folks) have been advising cleaning the TB by hand to resolve those symptoms and advising it for a LONG time. __________________

09-17-2003, 01:38 PM	#4
Chard AudiWorld Super User Account #: 1048 Join Date: Mar 2000 Location: Hawaii Posts: 8,038	TB = throttle body? what's it dirty from? I remember removing the hose that connects it to the top of the intercooler and seeing oil in there... __________________ Chard 1999.5 1.8tqms APR Stage 3 and some other good stuff

09-17-2003, 02:49 PM	#5
Yippers® Member Account #: 19399 Join Date: May 2001 Posts: 17,328	Yes throttle body. TB is also used to describe the timing belt but when used in reference to the idle etc .. it is throttle body It gets grimey from the oil vapors drawn in via the PCV system. The really small crude that comes in with the air that passes thru the air filter also contributes. __________________

09-18-2003, 08:10 AM	#6
Chard AudiWorld Super User Account #: 1048 Join Date: Mar 2000 Location: Hawaii Posts: 8,038	ah, so just take off the hose and wipe inside there? __________________ Chard 1999.5 1.8tqms APR Stage 3 and some other good stuff

09-18-2003, 08:25 AM	#7
Yippers® Member Account #: 19399 Join Date: May 2001 Posts: 17,328	Not nearly so simple. You need to get a new throttle body to intake manifold gasket from the dealer. IIRC it was like 50 cents or less. Disconnect the SMIC to TB hose, unplug the TB sensor wire, pull the cable (on the nDBW) and remove the TB. Once you have it pulled use a good, I like CRC brand, throttle body cleaner to clean the outside and the inside thouroughly. Use a q tip or similar to clean the area around the throttle plate and the plate itself. Pay particular attention to the edges of the plate and the area of the body the plate seats against when closed to the idle position. Do NOT use a carb cleaner as many of these have chemicals that can raise hell with coatings and plastics oft found on throttle bodies. Once you have everything spotless reassemble using the new gasket and do a TBA before starting. __________________

09-20-2003, 10:54 PM	#8
Stoney AudiWorld Super User Account #: 230 Join Date: Mar 2000 Posts: 5,267	Thanks! __________________ A6 (C5 platform) FAQ Stoney's Picture Library Email: jds@sonolithics.RemoveThisPart.com 2001 A6 4.2L, Sport, Premium, Nemo Blue, Melange Interior

09-20-2003, 10:55 PM	#9
Stoney AudiWorld Super User Account #: 230 Join Date: Mar 2000 Posts: 5,267	From the turbo's bearing oil supply also, I'm told. __________________ A6 (C5 platform) FAQ Stoney's Picture Library Email: jds@sonolithics.RemoveThisPart.com 2001 A6 4.2L, Sport, Premium, Nemo Blue, Melange Interior

09-20-2003, 10:57 PM	#10
Stoney AudiWorld Super User Account #: 230 Join Date: Mar 2000 Posts: 5,267	Thanks. I'm surprised this wasn't done on our car; I'll check our paperwork. __________________ A6 (C5 platform) FAQ Stoney's Picture Library Email: jds@sonolithics.RemoveThisPart.com 2001 A6 4.2L, Sport, Premium, Nemo Blue, Melange Interior

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