GT TDIi PD115 Huge power loss

[Gurmon]

Hi All,

First of all, I would like to say what a fantastic site.

Now, I have a problem which I can`t get my head round. I have spent hours searching this site, and ppl have similar problems but not exactly the same. So I thought I would add this post.

Ii own a 2000 PD115 golf. When you put your foot down in any gear, thee acceleration is totally flat. I mean its like there was never a turbo fitted to the car.

So, i plugged VAG-com in too see if there is any boost pressure. I was expecting to see none, and could then diagnose a fauly boost control valve (N75).

The mysterious thing is VAG-coom logs show that the car is producing upto 2210 mBar of boost. Which I believe is about 32PSI. Isn`t that too much boost ?

Now, if there is boost, why is the car behaving as if there is none.

Can someone please shed some light on this for me, oor provide me some more tests to carry out.

I would likee to check the hoses that would lead to the Boost valve, but where is the thing located ??

Thanks in advance

[Gurmon]

Anyone ??

[kow]

Sounds like your MAF has packed up, common fault, don't buy any other than VW as can give other minor irritating problems, easy to fit.

[leckford]

If you've got access to vag com there is an easy way to check to see if your MAF is knackered. plug vag com in, setup a measurement of the airflow and log it, then take the car to red line in 2nd gear. You should see a linear relation betwee the revs and the airflom reported by your MAF. check out the link below for a better discription, read the last paragraph. I did this the other day as i'm having some issues, i was able to determine my MAF is working fine, it's very easy test, just have to find the right bit of road to play around on :D

http://wiki.ross-tech.com/index.php/Fuel_Trim_Info (http://wiki.ross-tech.com/index.php/Fuel_Trim_Info)

[Gurmon]

Thankyou very much for your replies, Definately gives me something to work on, as so far the car hasn`t thrown any fault codes.

[gianni67]

I had a similar problem - split hose on the turbo waste gate was the outcome.

[Stevef.]

Hello , my car feels like that if the maf is unplugged, 32psi is way high for a standard car/turbo just for quick check you could pop the bonnet and get somone to give the car a bit of a rev if theres any pressure there you will see the top boost hose swell up as the car is revved, you wont get full boost but it sounds like your getting none at all, maf`s are a common thing to die on the tdis, the other thing to check are your vacuum hoses if you have a leak you will also not get full boost pressure the VNT mechanism in your turbo uses vacuum to control the exhaust flow to the turbine giving you more or less boost , if your intake/boost system is ok could it be fueling/timing.:)

[chrisp]

Almost certainly the MAF sensor, 5 minute job to change. 32 PSi on a TDi? Sounds very high.

[Gurmon]

Thanks for all your help so far.....

I'm beginning to suspect the MAF as well...

I can definitely confirm the car is making boost. you can feel the pipes pressurize when revving the car. Oh and its not making 32PSI..i forgot to minus atmospheric pressure....so in reality its about 14psi.

Now I turned on the measuring blocks that measure the air flow from the actual reading from the MAF and they are reading as high as 480 mg.... Isn`t that way too high ?

Anyone care to comment ?

[Gurmon]

Just wanted to post the resolution to this problem. Looks like advice was spot on.

A 5 minute MAF change resolved the problem completely. Seems all of the power is back.

Thanks all

[JohnHuson]

This may seem odd....but check your exhaust for obstructions, either for vandalism or damage to the cat or exhaust boxes. I once knew a horrible person who stuck a potato up the rear of a silencer unit. It took days to realise the problem as the engine would not run for more than a few seconds or at reduced power.

[Stevef.]

Good result mate!:approve:

[Alex s3]

Hiya mate,

I am in kendal too.

I need to plug my audi s3 into a vagcom where can i do this.

Thanks

Alex

[kow]

Not a clue, unless the guys at volkstec near EK brakes have such a device, they have a good name from what I've heard and were very helpful one Saturday morning when I needed a bit of grunt from their hydraulic press. Whats the problem with the Audi?