golf 1.9 TDI 'limp mode'

[dave_g1007]

Hi,

I seem to be having the same problem as have a number of golf owners by the looks of things. when driving (mainly motorways or up steep hills) the turbo decides to disappear and go in to limp mode, but when the car is turned off and back on it is immediately fixed and back to normal. also it seems to be doing low mpg (around 39) during long , steady motorway drives.

I have a Golf mk 4 1998 1.9 TDI

I've looked in previous forums on here regarding the problem, found that the mass air flow sensor could be at fault ,but when i have checked this it already seems to have been changed in the cars life as its not the bosch which i believe is standard? would this make it quite likely that this is not at fault?

Has any body got any other ideas?

Thanks

[Crasher]

What is the engine code or horsepower? You need to have a fault code read done, guessing can waste money. If you get code 17958, that is normally turbo vane carbon fouling but can also be an N75 issue, a vacuum leak or in rare cases it can be the Air mass Meter and in even rarer cases, the MAP (boost pressure) sensor.

[dave_g1007]

Cheers,

Its the 90 BHP.

How much does it cost roughly to get the fault code read?

cheers

[kite]

Look in the vagcom section for a member in your area.
Should be able to get a scan for a few beer tokens...

[Crasher]

90PS changes things a lot, which engine code?

[dave_g1007]

sorry for the delay in the reply (iv been off line for a while) im still having the problem!!!

Where do i find the engine code?
thanks

[wcubbin]

I had exactly the same problem on my Golf IV. My local garage said there were no fault codes but the turbo was down on pressure. They replaced an airflow sensor that they said looked knackered but that did not help. I took it to an independent VW specialist (ex-main dealer mechanic) who diagnosed it as a build up of kack in a nozzle inside the turbo, this was causing a pressure spike under certain conditions that told the ECU to put the engine into limp mode (killing the ignition just re-sets the ECU). He removed the turbo, sent it to a turbo specialist in Leeds who stripped it, cleaned it and put it back together. It now runs perfectly and I didn't realise just how much power I had lost! As this guy was a VW specialist but still had to send the turbo away I would suggest it is not a job for the home-mechanic. It cost 500 notes but this is much cheaper than a new turbo. I guess you could try treating it with turbo-cleaner before shelling out for an overhaul (I will be doing this as a preventitive measure from now on).