Author Topic: Turbo quit working??! (Read 5234 times)

sharpdan · « **on:** November 18, 2005, 05:31:54 pm »

I'm new to the Forum - I just got a 2002 Jetta TDI. While driving on the freeway this afternoon and coming up a minor grade, I lost power. I got of the freeway pretty quickly and rolled down the windows to listen for the turbo "whistle" while accelerating...but I didn't hear it or feel the "boost" when it normally kicks in.

I came home (2 miles or so), then let it sit for a couple hours. Decided to try it again, and it seems to be working fine now.

Could it be a sticky waste gate? That seemed to be the only topic listed on this site that addressed my symptoms....but it didn't sound like it would suddenly start working again if that was the issue.

Let me know what you think....Dan.

tackered · « **Reply #1 on:** November 18, 2005, 06:17:58 pm »

The little old lady borrowed your turbo for a bit.

Sorry, couldn't resist.

lord_verminaard · « **Reply #2 on:** November 18, 2005, 06:21:44 pm »

Hi, welcome to the forum. Firstly, the TDI does not have a wastegate, it is a variable-vane turbo design. The VNT15 turbo vanes have been known to sieze on the TDI's, especially if they are not "excercised". However, if they were indeed siezed, the car would not be acting normal the next day. Did the check engine light come on? If it happens again, try unplugging the MAF (mass airflow sensor)- it's the round "tube" with the electrical plug on the top of it in the air inlet hose between the airbox and the turbo. If it behaves a little better, then your MAF is faulty, a common problem with the TDI's.

Good luck!

Brendan
84 Scirocco 8v
00 Camaro L36 M49

sharpdan · « **Reply #3 on:** November 19, 2005, 08:32:18 pm »

Lord_V,

It did the same thing today as soon as I got out on the road. This time the check engine light came on.

I removed the MAF connector as suggested but I can't say it ran significantly better. Can the car go into "limp" mode? Also, I have an OBDII code reader, but I don't think the 2002 Jetta has the right connector under the dash.

I need to get a repair manual. Have you found that Haynes is okay?

I've only had the car a week, so this is a bummer, hopefully it will be something easy...thanks for your suggestions.

lord_verminaard · « **Reply #4 on:** November 20, 2005, 12:25:13 pm »

Haynes manuals are good for easy stuff, brakes, suspension, etc.. but for VW's the best way is the Bentley manual. As well as being more detailed and having lots more pictures, the troubleshooting guides are top notch. I know I would have been up a creek while working on my Scirocco if I didnt have one! You can get them at your VW dealer.

I'm pretty sure that most OBDII code readers wont work on a VW. If you have a laptop and a little extra cash laying around, RossTech sells VAG-Com software with a cable that you can use to analyze everything that the car is doing, it's very similar to the VW computer systems that the Techs use. I think it's around $200. But I'd still be willing to bet it's the MAF- I worked for VW parts for a little more than a year, and the only real parts we ever sold for TDI's were MAF's. (not counting all of the stuff that every other A4 VW needs, temp sensors, window regulators, turn signal switches, etc...) Other than a hard physical failure of the turbo, the only other thing that can control boost pressure besides the MAF is the N75 valve, a little solonoid that regulates vacuum to the VNT mechanism. But those dont fail as often as the MAF's do.

So you can take a chance, purchase one of those two parts and see if it fixes the problem, or you can take it to the dealer and pay the diagnostic cost to get the right item. Your call.

Good luck!

Brendan
84 Scirocco 8v
00 Camaro L36 M49

Wingaman · « **Reply #5 on:** January 03, 2006, 11:50:44 pm »

Humm, N75 Valve need cleaning ?

zyewdall · « **Reply #6 on:** January 04, 2006, 08:04:12 am »

Well, you've got a much more advanced engine and turbo control system than mine, but the symptoms also sound very similar to a clogged fuel filter. Especially one experiencing a little gelling issues. I thought the turbo on my truck went out two days ago when I completely lost power going up a hill (and my boost guage showed no boost any more), but it was just some gelled biodiesel in the filter. Went away after I got down to lower elevation where it was warmer.

Malacaco · « **Reply #7 on:** January 15, 2006, 10:04:38 am »

Ive seen many with that problem. if you turn it off and then back on and turbo works again it's the mass airflow sensor alright.