A5 TDI reccurring issues... anyone else?

alphaseinor

TDI Innovator Vendor , w/Business number
Joined
Jul 30, 2006
Location
Denton, TX
TDI
'03 Jetta TDI 780,000 miles (totaled out), 01 Audi TT 225 Quattro 230,000 Miles (runs great!), 00 Cabreetle Beetle dash, ALH & MK4 harness Swap
I'm starting to see recurring issues with the EGR valve on 05.5-06.5 cars... just wanted to see if anyone else is seeing this problem.

symptom:
Runs like it's missing at all speeds (history of 505.01)

1) unplugging MAF will make it idle, but no power
2) unpulugging EGR will make it run better
3) replacing (tried cleaning didn't work) will return car to "normal"

I've seen this about ten times in the last month. cars vary from 46,000 miles to 140,000 miles

This also seems to fix random hot stall issues in the summer time.
 
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slpopp

Veteran Member
Joined
Dec 18, 2005
Location
Central Minnesota
TDI
2005 NB GLS TDI DSG
Does it sound like it is on one cylinder?
Does it sound like "spark knock" on a gasser?

My 2005 sounds like it is missing on one cylinder, it seems very pronounced at roughly 2500 to 2800 rpm. "Beating" on it for a few miles seems to make the miss go away, but then it comes back a few hundred miles later. During the last few months of this winter I tried running 100% #1 fuel with 3oz of Stanadyne Lubricity formula for a few tanks (ran tank to less than 1/16 then filled up) and the miss seemed to nearly disappear. Dealer has checked into this sound but cannot figure it out. There are no codes and the engine appears to be running properly (according to the feedback from the ECU). There is also no abnormal vibration or other symptoms of a mechanical issue.

When the car is idling it sounds like one cylinder is not firing the same as the other three, either stronger or weaker - don't know which. I haven't tried unplugging the MAF to see if it affects the idle sound, but I do know that I have much LESS power with the MAF unplugged. I don't know how to unplug the EGR.

Seems like every know-and-then the car runs really well, but most if the time it has this missing sound along with being a little slugish. No missing sound and the engine performs very well.

I bought my car in March of 2005 so I don't think it is a 2005.5 model, but I do know it has the BEW engine.
 

alphaseinor

TDI Innovator Vendor , w/Business number
Joined
Jul 30, 2006
Location
Denton, TX
TDI
'03 Jetta TDI 780,000 miles (totaled out), 01 Audi TT 225 Quattro 230,000 Miles (runs great!), 00 Cabreetle Beetle dash, ALH & MK4 harness Swap
slpopp said:
Dealer has checked into this sound but cannot figure it out.
Doesn't surprise me... Dealer Technicians are rarely VW TDI certified. actually they are rarely certified in anything. They don't like your car since they can't figure it out.

slpopp said:
When the car is idling it sounds like one cylinder is not firing the same as the other three, either stronger or weaker - don't know which. I haven't tried unplugging the MAF to see if it affects the idle sound, but I do know that I have much LESS power with the MAF unplugged. I don't know how to unplug the EGR.
What type of oil have you been using (brand, viscosity, quantity, duration of change, type of filter)

slpopp said:
Seems like every know-and-then the car runs really well, but most if the time it has this missing sound along with being a little slugish. No missing sound and the engine performs very well.
I'd unplug the EGR on the front for kicks... what can it hurt? might have to reset a CEL tho...
 

slpopp

Veteran Member
Joined
Dec 18, 2005
Location
Central Minnesota
TDI
2005 NB GLS TDI DSG
alphaseinor said:
What type of oil have you been using (brand, viscosity, quantity, duration of change, type of filter)
I have been using the Castrol TXT 505.1 oil exclusivly (except for one time when the dealer didn't have the Castrol in stock and I used the Pentosynth equivilant). It is the 5w-40 weight and I go 5,000 miles between changes and use the VW oil filters. I do my own oil changes and I bought the car new. The car doesn't burn any motor oil and I check the oil level in the morning before I start the car, this seems to work out O.K. since the oil is cool but it has all drained back into the oil pan verses getting the oil up to temp and checking it "a few minutes" after turning it off. The cold engine at least gives a constant reading.


alphaseinor said:
I'd unplug the EGR on the front for kicks... what can it hurt? might have to reset a CEL tho...
I would try this but I don't know how to this on my '05 Beetle. I have Vag-COM (oh wait - VCDS) so clearing any codes wouldn't be an issue.


One thing that seemed strange over the winter was the car would run better on straight #1 diesel (with Stanadyne Lubricity formula added) than it did on 50/50 blended deisel:confused: .

EDIT - Adding to above winter statement - the car has had the fuel filter replaced several times already and it has only 43,000 miles on it. A new o-ring was used in the thermal T each time.
 
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alphaseinor

TDI Innovator Vendor , w/Business number
Joined
Jul 30, 2006
Location
Denton, TX
TDI
'03 Jetta TDI 780,000 miles (totaled out), 01 Audi TT 225 Quattro 230,000 Miles (runs great!), 00 Cabreetle Beetle dash, ALH & MK4 harness Swap
'05 beetle is a BEW
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H
The 05 Passat 2.0 PD wagon with 136k miles I'm considering has been unavailable for a test drive while the EGR was being replaced. Yesterday they finished replacing the turbocharger because "it felt down on power". I don't mind if the dealer throws parts at it while it's still his. I have yet to drive it to decide if I want it for my own.
 
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