Turbo Loss When Engine Cold

[dt1]

Hi folk. The turbo on my 2001 TDi Galaxy stops working and is fixed when I switch off and restart. I realise this has been covered by a number of posts but my problem seems a little different in that it only seems to happen when the engine is cold and I accelerate firmly before it has warmed up. I do not experience the problem if the roads are flat and I nurse the throttle. I can also accelerate as hard as I want once I have 'survived' the first mile or two so I assume the problem is temperature related. The problem used to occur only a couple of times a year but recently has deteriorated to the point that it happens almost every time I leave work and try to gain speed up a hill. Can you guide me where to look first please.

Thanks, David.

[anadin]

is your temp gauge stable , check all your small vac pipes, disconnect maf, and drive see if any different , or try and get it plugged into vag com

[dt1]

Thanks for the repy. The temp guage is stable. When I disconnect the MAF and drive the car hard from cold it does not cut out but it also does not develop full power. Is this normal?

[anadin]

Thanks for the repy. The temp guage is stable. When I disconnect the MAF and drive the car hard from cold it does not cut out but it also does not develop full power. Is this normal?

 

there should be a pipe on the air box , remove and check this , its sounding maf related , do a search on the maf , but vag com will tell you more , rather than spending first

[NikpV]

Disconnect maf - no difference or better usually indicates that maf is shagged, even if the performance is worse there could still be a maf problem, especially on TDI's what milelage is yours ??

 

see link here

 

there was some talk from folks that the thick film type sensor (as fitted to tdi) as opposed to the hot wire type should be a service replacement part often at about 50k

[dt1]

I've done 56,000 miles.

Anadin, I can't see any pipe on the airbox. Do I need to remove any covers to see it?

David.

[anadin]

I've done 56,000 miles.

Anadin, I can't see any pipe on the airbox. Do I need to remove any covers to see it?

David.

 

on the mk 1 , its a small vac pipe on the rear of the airfilter box , not sure on the mk 2, but its worth checking them all , before buying a maf

[NikpV]

without wanting to contradict you but when I did the maf (mk2) earlier this year I had the airbox out and cleaned it - I don't remember any other hoses/connections

[anadin]

without wanting to contradict you but when I did the maf (mk2) earlier this year I had the airbox out and cleaned it - I don't remember any other hoses/connections

 

bloody asbo's nick anything these days :o , never looked at a mk2 , but i have shares in vac pipes ;)

[dt1]

Is this helpful... Initial faults before doing any testing:

 

VAG-COM Version: Release 409.1-US

 

Control Module Part Number: 038 906 019 FA

Component and/or Version: 1,9l R4 EDC G001AG 1365

Software Coding: 00001

Work Shop Code: WSC 00020

3 Faults Found:

17965 - Charge Pressure Control: Positive Deviation

P1557 - 35-10 - - - Intermittent

17664 - Shareware Version. To Decode all DTCs

P1256 - 35-10 - Please Register/Activate - Intermittent

17552 - Shareware Version. To Decode all DTCs

P1144 - 35-10 - Please Register/Activate - Intermittent

[dt1]

Reset codes, drove car from cold, experienced turbo cutoff, then had following code:

 

1 Fault Found:

17965 - Charge Pressure Control: Positive Deviation

P1557 - 35-00 - -

[dt1]

I appear to be getting a MAF error only after disconnecting it (which might be why it was in the first set of three):

 

17552 - Mass Air Flow Sensor (G70): Open or Short to Ground

P1144 - 35-00 - -

[anadin]

again on the mk1 upto 2000; the charge pressure control valve has vac pipes coming off it ,and you also have a charge/air temp sensor on the air duct from the intercooler to the intake manifold , some one with a mk2, will have to give you their locations

[dt1]

Time to buy a manual I think!

[sepulchrave]

This forum is better than any manual you can buy (mostly, irrelevant nonsense aside)! :wub:

[NikpV]

btw maf faults rarely show up as dtc on vag-com unless missing :wub:

[anadin]

btw maf faults rarely show up as dtc on vag-com unless missing :wub:

 

yep i would agree with nik, it certainly carn't be discounted

[NikpV]

in this case definitely have a vacuum/turbo problem but I would lay money on a problem with the maf as well - the faults may be interacting when cold or maf be copletely separate.

[tim-spam]

Any update on your problem?

[dt1]

I intend replacing the MAF first. I've been waiting for a few ebay sellers to tell me if they sell Bosch or clones. I've had no reply so I assume they are clones. Looking at the number of problems caused by the MAF I think a genuine component is wise. Hope to do it this week.

 

Since my problem appears to be temperature-related and I had a coolant sensor error, this is probably the second thing I will change if a new MAF does not correct the problem. Although the sensor is cheaper (

[Dave-G]

FWIW - the MK2 does not have vacuum pipes off the air filter box.

 

I also suspect the t-map sensor is involved in this, as this is a temperature related component. I recently had to replace mine...

http://www.fordgalaxy.org.uk/ford/index.ph...wtopic=9370&hl=

get comfy first - or go straight to post number 30... para 2... The other 2 faults listed were "manifold absolute pressure sensor" and "manifold temperature sensor" There was also something about positive deviation and open/short circuit somewhere, I cant remember where the guy said that wa :D

 

When it got HOT it lost power ;)

 

I may have to look in this direction again because when cold, auto gearchanges are "thumpy" - a trait I found when I tried running the car with it unplugged ;)

[tim-spam]

I would agree. Unless you have a general lack of power when the engine is operating normally when warm, I wouldn't bother changing the MAF - MAF faults generally affect performance all the time (and are often worse in the warm weather), and are not resettable by keying off and on again.

 

From the VAGCOM diagnosis, there is a boost control problem, and the causes are usually (in ascending order of cost):

 

1) Dirty boost control solenoid filter (looks a bit like a small in-line fuel filter and is located below the air cleaner). Try disconnecting it - if the problem goes away, fit a new one.

 

2) Leaks / blockages in one or more vacuum hoses - if in doubt, change the lot.

 

3) Boost control solenoid.

 

4) T-MAP sensor.

 

5) Turbo vanes sticking - normally requires a new / recon. turbo to fix permanently.

 

Hope this helps.

[dt1]

Having read many posts on MAF problems I formed the view that mine was not perfect. So I decided to replace it anyway which I did a couple of evenings back. General drivability is smoother with better acceleration. It has given me a little more power before the turbo cuts when cold but has not solved the problem. It's given me much more power in 'limp mode' which is helpful.

 

Thanks for the other suggestions. I've not folowed them up yet but will.

[dt1]

Tim, Do I need to remove the air filter to see the 'boost control solenoid filter'? Is it an electrical device (am I looking to disconnect wires, tubes...)?

Thanks, David.

[tim-spam]

You can see it with the air cleaner in place, but to reach it, you will probably need to take the top engine cover off - it's just below the large hose leading from the air cleaner. With the air cleaner off, it is dead easy to reach.

 

It isn't an electrical device - it simply filters the air supply to the boost control solenoid valve, and if it gets blocked / restricted (or the hose from it gets blocked / restricted), the turbo vanes are slow to move back to maintain boost pressure, and the boost pressure overshoots, leading to the switch into limp mode and the positive deviation fault code in VAGCOM.

 

In normal operation, vacuum is applied to the turbo control diaphragm via the boost control solenoid valve, to increase boost pressure. When the engine speed reaches around 2000 rpm, the vacuum applied by the boost control solenoid valve to the turbo contol diaphragm is reduced, such that the turbo vanes move back to maintain the boost pressure at the correct level. The vanes move back by virtue of a return spring, and in order to allow for this, the diaphagm needs to draw air in - this air comes in via the small filter, a length of rubber hose, the boost control solenoid valve, followed by another length of hose to the diaphragm.