as above on my way home from track day my 1.9 tdi golf decided that the turbo would stop on the way home no sing of prob b4 stopped at next service station had a look no smoke no sing of a prob turned car off then back on gave a few revs. then palled off and turbo was fine and still is what could of happend is the turbo on its way out
thanks terry

sounds like some electronic going into safe mode.

I had a MKIII that did that from time to time, it's the air flow sensor, it could be on the way out or maybe just needs a clean, was you pushing on, maybe into a strong wind, thats when mine used to trip out.
Brad.

Without knowing the symptoms of what you say happened - ie loss of power, funny noises, change in exhaust note that made you say the turbo stopped we can only guess at the problem so here's mine:

If there was no smoke I would suspect that the wastegate stuck open so turbo couldn't make boost - when you stopped the change in state - ie cooling of exhaust and/ or change in manifold or exhaust pressure allowed it to unstick and return to normal operation.

Sounds like the airflow meter. Very common on Vag tdi's.

See if it does it again.

second the air flow meter

On these cars they don't have a wastegate they are VNT turbos so none is needed - however the principle is the same, if it sticks in one extreme position then no boost, sticks the other way then lots of boost then bang as it overspeeds.

yea very slow when that happens and i was towing a car.

and i did say no noises no smoke

thanks for your replys

Probably the MAF sensor. It'll come and go at random. When it's playing up disconect the sensor and see if it improves. It won't run perfect but will be better if the sensor is US.

adrian

The VNT mechanism can seize up/stick aswell.

[Edited on 14/7/08 by Danozeman]

We've had VW, Audis and Skoda's come into work with this problem.
MAF sensors are fav
Second is the "Pressure charge sensor" sits on top of the inter cooler (skoda and A3).
Either one of these two has always fixed the problem

HTH

John

if it's a one off, unlikely to be MAF (but granted they are a very common failure - you more notice a general/total drop in power), more likely a slightly sticky VNT mech causing the engine to overboost and hence go into limp home. Could also be an N75 valve starting to go (which controls the VNT). As you'd been treating it mean, might be worth checking no vac pipes have come adrift - these could cause this - otherwise keep driving it, it may not happen again or it may become more repeatable meaning you can diagnose. Don't worry too much though!. If it does start happening more often, get the car scanned by somebody with VAGCOM, error code will give a clue, but usually just says something like 'infeasable boost pressure'.

HTH

Greg

If you turn the engine off and then on again and it is fine then it is going into limp-home mode.

This is a common problem which can be cause by MAF failure (or dirty), or leaks in the tubes around there.

For more information:
http://www.vwaudiforum.co.uk is very good

Matt