6 speed TDI JSW stumble/stall
I have a 2010 JSW TDI with a 6 sp manual and 7,500 miles; I have experienced the stumble behavior since the very first drive home from the dealer last October when I purchased the car new. The first time it occurred, I knew it was totally out of the ordinary, and challenged the dealer to check codes and diagnose. I described the sensation as a missfire or fuel cut-off. They claimed it was normal TDI performance and sent me on my way. The vehicle has continued to stumble frequently since then, and has been in out of the dealership 4 times to no avail (though they've slowly revealed that they acknowledge the issue as a problem and are working on a fix... see below) as the problem continues. Here's a description of the issues I'm experiencing, all of which appear to be related IMHO:
1. The first characteristic is a stumble at approximately 1,800 RPM just as I release the throttle to upshift from 3rd to 4th gear. The engine appears to cut out for a split second and then jump back to life. It seems to only occur on flat, straight stretches of road and at about 30-35 MPH during moderate acceleration. The stumble here is a single event and the car then proceeds as normal from there forward -- usually not stumbling again during that drive. tt appears to do this only after the car has been parked outdoors (vs in my garage) for a few hours (usually does it during my lunch-time drive after the car's been parked outside at work for 2-3 hours). I would say this occurs once every 4 trips or so. The car has done this ever since my very first drive home from the dealership a year ago. It doesn't matter where I fill up with gas as I've changed stations to see if it's a fuel thing to no avail. I would characterize this issue as more annoying than a safety issue. The safety issue comes later...
- The first 2 visits back to the dealership to have the issue checked, they said there were "no codes" and the vehicle was "performing normally and that the sensations were related to the different torque characteristics of a diesel engine." The service dept also told me "there's no way for a diesel to missfire because it's a compression engine..." Thanks, guys. Not helfpul.
- The 3rd visit to the dealer, they said there was a service bulletin for a software flash and O2 sensor replacement; they reflashed the engine and said that that would fix it. The problem persisted.
- After 4th visit, this one in August, I provided links to the tdiclub.com and myturbodiesel.com forums to the service department; the dealer then came back with this reply, finally acknowledging the issue:
In talking with the shop foreman, Volkswagen is aware of the situation. There is an impending software level update, I believe the issue resides with the EGR system and possibly the regeneration of the particulate filter. Unfortunately VW has not given us the fix. What I would recommend is contacting VW Customer Care and initiate a claim through them, trust me though as soon as I know when this update is available you will be the first to know. VW Customer care's number is (800) 822-8987.
- at the dealers' suggestion, I reported the incident to VW Customer Care
2. The second characteristic is a hesitation sensation when cresting a hill and naturally releasing pressure on the accelerator pedal as I crest the hill. As I proceed down the slope the engine feels like it's hesitating -- not stumbling as it does on the straightaways, but instead just needs a pretty good goose on the accelerator pedal to respond. This appears to be most prevelant at speeds below 50 and doesn't seem gear dependent and more so tied to the releasing of the throttle following an ascent. I would say this occurs more frequently than the single stumble - probably once every 2 trips or so. No warning lights present themselves in any of these instances. And the dealer says no codes are found.
- The dealer service department, despite 4 visits to address this issue, had not been able to resolve it as of August, 2010 and the problem persists
3. The third characteristic, which has actually occurred only once in the year I've owned the vehicle is, what's best described as a slipping-clutch sensation during acceleration after shifting from 1st to 2nd gear. Unlike the first 2, this one happens when the engine is loaded and with pressure on the accelerator. Whereas 1 and 2 happen when feathering the accelerator. This one is much more concerning and, in my opinion, dangerous as the vehicle shakes and has limited power. I think I counted what felt like 4 sequential stumbles that felt like the clutch was slipping. My passengers looked at me like I was driving like a beginner. I KNOW it wasn't my driving and it was clear that I wasn't in control of the engine during this incident. It stopped after 4 or so consecutive stumbles and car continued to drive normally for that engine cycle. Again, no warning lights whatsoever.
- The car is now back in the dealership for this issue as I refuse to drive it any longer
4. The 4th characteristic, which thank god only happend once, was a total shutdown of the engine during braking after cresting a hill at the top of which was a traffic light, which had turned red. The similarities to 1 & 2 in this one was that it involved the cresting of a hill, and the release of the accelerator (after significant pressure, traveling at 50+ MPH while climbing the hill approaching the light). The engine was very warm as I'd just driven for an hour at 75+ MPH on a freeway. So, that's different from the cold-start stumbles on the straigtaways that I've seen with point 1. Anyway, I approached the light, braked with moderate force and noticed that after I'd come to a stop that the engine had stalled out. No power at all. Surprised, I went to start the vehicle and it seemed to take 2-3 times longer to crank. It eventually cranked and then spewed an alarming (think raging camp fire after water poured over it) of thick WHITE/GREY smoke from the tail pipe. So much so that my passengers asked if the vehicle was on fire! No warning lights presented themselves during this massive smoke episode and the car then drove normally thereafter.
- Needless to say, this was the straw that broke the camel's back; i took the vehicle back to the dealer and told them it wasn't safe to operate and that I wasnt' interested in driving it any longer. Oddly, that same day that I took it back, I received this email from the tech advisor:
I spoke with one of your area reps. Friday about the software update being available yet on your vehicle. He is in Detroit this
week for meetings and he is going to speak with some of the engineers. They are using the software update currently, but he is unsure if it is fixing the issue. He is going to contact me when he gets back to let me know if it takes care of it. I don't want you to think we've forgotten and I will let you know hopefully be the end of this week. If you have any questions please let me know.
- I reported the incident to VW Customer Care, and filed a case report with the NHTSA as I believe this is indeed tied to the stumble issue and is a major safety issue; these cars need to be recalled and repaired
- I took the car back that day and am now driving a loaner
- In the meantime, I found stories about the NHTSA investigating stalling issues with VW TDIs that discussions on the tdiclub.com forum suggest are tied to fuel pump failures; while the initial conversations around the stumbling issue appear to be related the EGR valve and the software that governs the regen function, I wonder if the stumbling and stalling are tied to the same issue as I've had both failures (though my stall didn't render the vehicle undrivable like the fuel pump failures being investigated by the NHTSA). I also wonder if the stumbles I'm feeling are also tied to the fuel pump... the stumble could easily be a loss of fuel to the engine -- at least it seems logical....
All of this has me gravely concerned. Concerned about my investment in a vehicle that appears to have a serious design flaw. Concerned about my safety in driving the vehicle. And also really disappointed (because I'm a huge VW fan, believer in diesel technology and someone who waited 4 months for the vehicle to be delivered) that VW doesn't seem to be able to identify the issue.
In the meantime, my dealer says they're updating my ECM with a software update that's supposed to address the EGR issue that they believe is contributing to the stumble. They're also testing my fuel to see if it's to spec/contaminated (which I doubt). And they're assessing whether my incidents above are all related, or seperate. I don't want to drive the car again until all of it's addressed. I'm considering filing a Lemon Law claim in Washington State in the meantime and am awaiting those documents before proceeding.
I'm also awaiting a call from a VW tech to explain to me their position, their guesses, and their methodology for drilling down into the causes of my isssues. VW Customer Care promised I'd receive a call from a VW regional tech in 48 hours.
My dealer's doing the right thing now by taking the car back and giving me another (non TDI) Jetta to drive in the meantime. In the meantime, it's now up to VW to approach the very loyal (and fanatical) ambassadors of their TDI technology in the US who are having these issues, hear the complaints and be honest about their assessment and their attempts to fix them. I'm all ears....