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Discussion Starter #21
You are right, they were not in the recall. They have been revamped and are under a new part number now if ecstuning is correct.

No error codes at all, which is what is making this so hard to diagnose. I did notice something iffy about the MAF. It NEVER zeros out. When car is turned on, but without starting the engine, MAF reads around 1.6 g/s. Is this normal? When I looked at the airbox, I noticed a greasey substance around the rubber of my old air filter. I assume this was from the previous owner using a K&N oiled filter, which could affect the MAF.
 

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As I understand it, the Mass Air Flow sensor measures air mass by determining the voltage needed to heat a hair sized wire (which is why any contamination by either touching it with your fingers or getting oil etc. on it is fatal).

Because the element is so thin it can be heated and cooled very quickly. When voltage is applied, the wire is heated and as air flows over it the element cools down needing more current to keep the wire element heated. The MAF transfer functions tells the ECU how much air must flowing to maintain a certain voltage. These values need to be correct for the air flow at a certain voltage for that particular MAF unit. Different MAFs have different air flow characteristics and of course are affected by the addition of CAIs for example.

Neither ambient air temp nor altitude "fools" the MAF, because when the temp is colder and the air is more dense, the wire will be cooled more by the colder denser air telling the ECU that more usable air is flowing by. When the air is warm and less dense or at high altitudes, it doesn't cool the element as much so the ECU knows less airflow is available.

Thus any contamination (you mentioned oil) due to oiled CAI or air filters will cause the wrong values to be sent making the ECU adjust the ratio of gas and air that ends up in your cylinders.

Alas I have no info on what the normal g/s values are, but based on your lambda value of 1.6 ,I would venture that you're running very lean which is causing your engine to starve to death. More info can be gleaned from

Fuel Trim Info - Ross-Tech Wiki

Your VW shop should be able to get the correct values for you. When they do please post them so we can refer to them if need be. HTH

siberian
 

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Terry - not to inspire confidence here - I take mine to Westside too - is that there has been a mass exodus of techs from their bays in the last few months. I heard (through the grapevine) that they don't even have a Master certified mechanic on staff any longer.

Take it for what it's worth - but it might explain some of the difficulty you have been having with a "complex" issue. As in - they are great at oil changes, but when it comes to diagnosing issues, they rely on the computer since they don't have the knowledge and experience. I'm sorry you are having such issues.

Don't be afraid to escalate it to the GM either (before you call VW USA). I'm pretty sure he will light a fire under some folks. His name is Steve Hendricks and he is a very nice gent. He does a good job of making things right for the customer while also (I assume) making things right for the dealership.
 

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Discussion Starter #24
I've worked with Steve in the past. Very good GM and has lit fires for me with my Jetta! I am hoping they can nail this down today, I can whole heartedly believe they are missing a lot of techs. No one seems to know what the next step is, so I'm guiding them along with my knowledge of old VW VR6s from the early 90s!
 

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Boy, am I glad I found this thread... my '09 3.6L (31K miles, new to me since July of this year) has been doing this off and on (mostly on, mostly 1st thing in the morning). Never any codes set on mine, either.

Took it to the dealer a few weeks ago and of course it didn't do it since I did not leave it overnight, but I did play them an MP3 of it starting that morning... popping 3 or 4 times, and running rough for the first ~ 20 seconds.

I tried uploading a copy of the .mp3 (600Kbytes) but the forum said invalid format -- does anyone know how I can post it ? I could just change the extension to .TXT but there must be a reason they don't want .mp3's uploaded... maybe a moderator can tell me if it is OK to post a 'recording' I made myself ?

The tech said he never heard such a thing; he reviewed the bulletins and came back empty. I have an appointment next week - when they could arrange a loaner - to leave it long enough for them to (hopefully) duplicate it... after reading this thread I'm more pessimistic.

I don't know whether it will help or hurt to print out a copy of this thread when I take it in... guess I'll decide before Monday.

I did find one thing that seems to cause it NOT to happen...
Normally I go right from key in, to crank. If I instead turn ign on (but don't crank) for ~ 10 seconds, then start it... it has never done the popping. Might be something for others to try to see if yours acts similar...

Speaking of crankcase breathing and such... I notice if I remove my oil fill cap with the engine running, it stumbles and runs very poorly... but believe that to be a sign of a properly working PCV system, no ? Like checking the operation of the PCV valves on the older engines by unplugging it from the valve cover...
 

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I performed the key to ignition, turn key like i was starting it but without foot on brake wait 10 seconds and then crank and it and it did not pop at all. Makes you wonder if there is a flap that closes after motor cools off and needs a few seconds to open it back up when you start it cold.
 

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Discussion Starter #27
I let the dealer know about the 10 second rule and they gave it a try yesterday: No Popping. That really didn't solve anything for them, but at least gave them some additional troubleshooting. They are replacing the breather valve tomorrow (supposedly) because they verified it isn't functioning very well (oil blowby). The next step after that is complete is re-verify the coils.

2 weeks its been gone on Tuesday. At least my loaner is running great!
 

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I'll be dropping mine off a the dealer this afternoon; interesting to hear that the key on / no start for a while behaves the same for others -- even if as you say it doesn't really say what the problem is, just another bit of information.

I wonder if by not cranking immediately it's letting something vent (similar to temporary removal of the vent tube before starting, which you said also caused it to not pop and smoothed out the idle)
 

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Discussion Starter #29
Pancho- Let me know what progress your dealer makes. Might be worth giving them heads up that they are battling the same beast!

More news: Asked them if they checked a fuel pressure issue. It's a little out of the blue, but with the 10 second rule working, it makes it a little hard to believe its a coil or vent issue. My thought is the fuel pump is going back and not priming the HPFP with enough gasoline. This would create a lean status and misses without creating an error code. Once up to pressure it does great. 8-10 hours of sitting would bleed the system pressure down.

This would explain many things:
Occurs regardless of ambient temp
Occurs after 8-10 hours of sitting
Does not occur is you allow car to sit with ignition on
Does not occur on restarts after car runs for 30-40 seconds
Fuel pump making some odd noises
 

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terrywood02 - I read in an earlier post you said yours was at a dealership named Westside... what city / zip ? I plan to tell my dealer about this thread and hopefully they will consider calling yours to compare notes, if it comes to that... might save everyone some time.
Mine will be at Flow VW in Greensboro, NC http://www.flowvolkswagengreensboro.com/
 

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Just a thought, but are you hearing the fuel pump at all when you open the door? I know my 04 was like this as well as everyone elses I knew with a gas motor. It would prime the pump as soon as you opened the door when off. I don't know if my TDI does this at all or not, but know the gas motors did and you could hear it. Could be your not getting that and your 10 sec deal is doing exactly that, priming the pump first.
 

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I do hear mine when I open the driver's door...

Dropped mine off at the dealer last night, the SA that did the check-in didn't want to hear anything about anyone else having this same problem, or about anything else I have been doing to help troubleshoot the problem. Just said they'd take care of it........
I plan to call the SA who helped me the 1st time today.
 

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Discussion Starter #34
I can here the fuel pump, but it re-primes every 2-3 minutes if you dont start. On my MK4 Jetta, this was a symptom of a bad pump and was killing my power at high RPM.

Brought this up to the dealer and they are investigating it this morning.

Good news: Last 2 days they have started it with no hesitation and no idle issues. They say drivability from start is about 85% improved (a very scientific and precise measurement), not perfect but immensly better. They have done a lot more work than I have stated evidently, so once I pick it up today I will post a rundown on what was completed.
 

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Discussion Starter #35
I do hear mine when I open the driver's door...

Dropped mine off at the dealer last night, the SA that did the check-in didn't want to hear anything about anyone else having this same problem, or about anything else I have been doing to help troubleshoot the problem. Just said they'd take care of it........
I plan to call the SA who helped me the 1st time today.
Yikes... I am pretty picky with my SAs and that guy wouldn't have lasted two minutes. If you do get resolution please let me know!
 

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My fuel pump comes on as soon as the door opens and it still pops. I have been talking with the service manager on this problem at Don hewlitt in Georgetown tx, just north of Austin, great service, great people. I called him yesterday and he called me back late and I wasn't able to talk to him. I will call him back today and ask him what goes on when you just give the car ignition (like you are going to start it but you don't have the brake peddle pushed.
 

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Discussion Starter #37
Well we have partial resolution:

Multiple things were wrong
1. Line from generator to controller was cracked and corroided, leading to a huge voltage drop
2. Throttle body was not actuating as fast as it should have (side effect of #1)
3. After bodyshop work for a month+ this year, some of the basic settings in the engine had been lost, reset automatically when the engine was first started up, and set incorrected. They fixed this with a factory proceedure called "Repair Readiness" where all engine basic settings are reset correctly through an automatic system.

4. Cam adjusters are the biggest culpret of the misfires. For the first 30-40 second on a cold engine, they were/are moving very unpredictably. They are going to continue to research this and one VW Tech gets back to them, they will call me with a loaner to have that addressed.


This morning I went to start it: 1000 RPM then dropped to 800 in about 10 seconds. Not a shingle stutter or shake until the EGR systems started dumping, which it the normal warm up shimmy of the VR6s
 

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So terrywood02 -- has it been determined that the popping noise is in fact a misfire ?
A cause, or an effect ? I could see the misfire counters triggering on any RPM variation that the control system did not think should be occurring...

Got a report on mine yesterday, they tried all day to reproduce the problem... no luck.
I reminded them that it only does it usually 1st time, and they should be trying to start it immediately after inserting the key. I could see them turning the ign on, connecting the scan tool waiting for data, etc... which would by then invoke the "10 second rule" as terrywood02 calls it now :)
 

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Discussion Starter #39
I did verify it is a misfire based on the counters. Sadly the ten second rule failed this morning. I will be checking it tonight with the vag to identify which set of cylinders is missing. I believe it is 1-3-5 which would make the cam-adjuster idea seem VERY solid. If i recall properly I was seeing between 4-6 misfires on that line, while I had 0 on the other.

It goes back in next Thursday for further work.
 

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Bummer....

Mine had been at the dealer 1.5 days with the techs unable to reproduce, I went out yesterday and it finally occurred when I started it... maybe it's me. (Actually I think they had been leaving the IGN on).
They have opened a "VTA" case whatever that is, I imagine a call to the tech / hotline...
 
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