Loss of Power Golf TDi Mk3

[pritesh]

I'm new to this and apologise in advance if this has been talked about before.

I have a Mk3 Golf Tdi with 120K on the clock. Recently my car has been losing power when in 5th gear and going up hill. I would have to take my foot off the gas totally and then apply gas again to pick up speed and thats when i see faint whitish smoke coming out from the back. If i keep my foot on the gas then the speed will pick back up once i have gone over the hill.

Does this mean my turbo is gone? or is it my MAF? or could my headgasket have gone? Has anyone else had this sort of a problem before and what was the out come.

All help and suggestion would be most welcome.

[tornadored7]

Hi Pritesh,

I had almost all of the same symptoms as you have experienced, i.e. 5th Gear up hill the car would { lose power, jolt, stall, jerk } , then need to reapply power by releasing accelerator pedal, then reapplying power.

This could be due to numerous things, and I would check the following in order;

• MAF (Pierburg on a G3 TDi, 1Z engine)
• MAP to ECU hose leaks (hose is located on intake manifold)
• Turbo hosing (3 hoses to check)
• N75 (boost control) valve
• 'Italian' tune up
• Exhaust/cat clogged
• Intercooler / hosing
• Turbo

* Blue indicates an issue in the Boost control path.

My symptoms were very similar but IIRC didn't experience ' faint whitish smoke coming out from the back'.

1) MAF

At about the same sort of mileage as yours (~120K), my car would suddenly jolt lightly and stop applying power (but only when accelerating in 5th). Since the 1st Gen Pierburg MAFs MAF imperceptibly degrade in performance over time, this was my first suspect.

I removed my MAF, carefully sprayed it with electrical contact cleaner/carb. cleaner, and after properly drying and reinstalling, the car was driving like new . Significantly more torque and power. The effects were however short lived, reverting to the degraded performance within a few weeks.

Other people suggest unplugging the 6 pin electrical connector to the MAF and checking whether this improves performance. In my case this made things worse, but paradoxically doesn't eliminate the MAF as faulty.

Using VAG-COM or other OBDx DTC scanner, it is possible to compared actual/expected MAF airflow for discrepancies and isolate a MAF problem. Instead I knew the MAF was the most likely suspect and just ordered a new Genuine Pierburg MAF from a VW dealer (VW part number: 074.906.461, aka Air Volume Meter)

Again the result was like driving a new car. No more stalling/jolts in 5th gear, and a smooth progression upto 4K RPM (would previously stall around 3K RPM). Unlike cleaning the MAF, replacing has a more permanent improvement.


2) Boost Path

The stalling could also be a limp mode issue, suggesting the Boost control path. Ideally use VAG-COM to check for Diagnostic trouble codes. To avoid the risk of repetition, check the following threads;

https://www.vwaudiforum.co.uk/forum/showthread.php?t=5705
https://www.vwaudiforum.co.uk/forum/showthread.php?t=5560

In a nutshell I would first look at replacing/diagnosing the MAF (Mass Airflow Sensor), particularly so if you are still using the original factory fitted (check the date [MM/YY] on the MAF) or a non genuine replacement MAF, and also since this is such a common issue. The Turbo is a very expensive route to start, and several orders of magnitude more durable than the MAF

Please let us know what you think and how you get on ...

[pritesh]

Hi Tornado Red,

I had read many forums on here and the tdiclub and in the end felt it was the MAF. But the one thing that kept going thru my head was the whitish smoke which put doubts in my head that it could be the turbo.

Anyway I have since given the car to my garage. They have put the car on the computer and told me that the turbo is blowen. I am getting the turbo replaced on thursday. But I have got the car back and it smokes in every gear and it is now quite obvious that there is lack of power. The car is also more nosey but I have been told this is due to the car thinking theres not enough power so feeds the engin more fuel - since the turbo is not orking as it should be.

Having said this I still can feel the turbo kicking in in gears 1-4 with smoke. But I guess over time the turbo will totally pack in. I have spoken to a few garages and they say the on the Mk3 golfs its not normal for the MAF to go.

I now just have to wait till the end of the week for my new turbo to be fitted. I have opted for a recon turbo which is costing me £285+Vat and the labour is £100 which i thought wasnt too bad, whats your views?

[pritesh]

When I get my Turbo I will try and take a photo of it and thn take a photo of my blown turbo to show others the difference.

[tornadored7]

Hi Pritesh,

'I still can feel the turbo kicking in in gears 1-4 with smoke', does sound worrying like a turbo issue. Consistent white smoke while accelerating is potentially turbo seals leaking significantly, allowing engine oil ingress into boost path/intake manifold.

How much engine oil does your car use, is it a lot higher than normal ?

I have spoken to a few garages and they say the on the Mk3 golfs its not normal for the MAF to go. , while the MK3 Pierburg MAF is more resilient than the Bosch, it will still degrade with time, requiring eventual replacement.

They have put the car on the computer and told me that the turbo is blown. Probably the best way to diagnose is using VAG-COM, scanning for DTCs and checking the actual/expected boost pressure at the MAP (or using a pressure gauge).

From what I can gather, it does sound like the turbo, but I wouldn't really expect that from a car with only 120K miles. However, YMMV according to driving style, quality of oil and regular servicing.

While the turbo is being replaced, would be a good idea to replace the turbo hoses (red,blue,black) IIRC, since these could leak later on, with blown turbo symptoms.

Let us know how you get on, and also recheck TDIClub.

Best wishes

[pritesh]

Hi Tornado Red,

To be honest I have not checked how much oil the car has been burning but generally the car has been pretty good to me. Between oil changes i noramally top it up with an extra 1lt of oil.

I dont thrash my car. Most of my driving is motorway driving and i generally drive about 80MPH all the time. I have recently read on the TDIClub that with TDI engins its best to rev them up to 2500rpm before changing gear while the car is cold and once its warm you change gears after 3000rpm, Has any tried this and is this correct? I tried in while i was on the motorway and i was driving like about 75MPH in forth gear before i hit 3000rpm on the rev counter is this correct?

I will get the turbo hoses changed while the turbo is off - thanks for the advice.

[tornadored7]

Hi Pritesh,

The general idea behind high revving the engine, is to keep the boost path clean, since the normal very slight oil leaking from the turbo will otherwise accumulate in the intercooler/intake pipes. This also excercises the the turbo and wastegate and finally helps clear soot accumulation. Paradoxically, overdoing this goes against the economy raison de etre of the TDI .

I consider it good practise to occasionally high rev your engine ~4K RPM for about half a minute on the motorway, but only after the engine is properly warmed up, and with a known good timing belt, to help clean oil and soot accumulation.

Keep an eye on your oil level, and also check that you are using a good TDI VW approved 10W40 type oil.

BTW, on a mild/warm day do you get a lot of smoke when you start the car, or experience difficulty starting the car ?

[pritesh]

Hi Tornado Red,

What I did find was that once the engin is warmed up and i revved past 3000rpm i could feel some extra boost kicking in. So what is best for the Turbo revving it high or 'babying' ?

I use fully synthetic Castrol magnatex oil. I did start of using Quantam oil which i beleive is VW approved oil. When replacing my turbo i'm getting the oil changed in the car too is it best to get the engin flushed at the same time too?

Regardless of the weather i have never found the car to smoke at all and it will start up on the first click everytime without fail.

[pritesh]

A update on the car. On wednesday I went to buy a recon turbo for the car, was going to cost me £250 which i thought was pretty good. I got talking to the Turbo guy and asked him to see why my turbo was blown. He didnt think my turbo was blown and started to check my pipes. He found one of the boost pipes had been cracked. He told me to replace that and see how i got on. Having replaced the pipe and driven about 200 miles the car feels like its full of power again and no more smoke. While changing the pipe i also changed the oil oil filter fuel filter and put in some cat cleaner so hopefully this will clean up the system and get rid of any rubbish thats in the system. I think i have been lucky that nothing went into the cracked pipe and into the trubo as this can cause the turbo to blow.

I'm glad the guy at the turbo place had a look at my turbo. I know if my turbo does go I will goto them.Excellent service. They are based in Brentford Middlesex called Turbo Developments and Engineering Tel 0208 560 3927.

[tornadored7]

... He found one of the boost pipes had been cracked. He told me to replace that and see how i got on. Having replaced the pipe and driven about 200 miles the car feels like its full of power again and no more smoke.

Hi Pritesh,

That's excellent news , and I'm very glad that your car is back to a high level of performance.

I take it when you say boost pipe, you actually mean one of the black large diameter hoses that leave the turbo and route to the intake manifold via the intercooler ? If so, would it have been possible to hear the pipe hissing, with leaking charged air ?

... While changing the pipe i also changed the oil oil filter fuel filter and put in some cat cleaner so hopefully this will clean up the system and get rid of any rubbish thats in the system.

Sorry to be so ignorant and Kitty jokes aside , but I haven't tried cat cleaner.
What is cat cleaner and where can you buy it from ?

I think i have been lucky that nothing went into the cracked pipe and into the trubo as this can cause the turbo to blow.

I agree, and think that you are fortunate, as are we to learn from this. If you hadn't shared your experience with us, we wouldn't have known that when a TDi is low on power, it can (amongst many things) suggest damaged hoses, which if not diagnosed and treated early can prove to be far more expensive delayed repairs.

I'm glad the guy at the turbo place had a look at my turbo. I know if my turbo does go I will goto them.Excellent service. They are based in Brentford Middlesex called Turbo Developments and Engineering Tel 0208 560 3927.

That is great service, thanks for the recommendation.


Finally, on a personal note I tend to drive my car car gently before it is warmed up (i.e. Engine temp hasn't reached mid guage), then high rev and push the engine hard at least once per session.

Best wishes,
TR7