golf gt tdi (115bhp) 1896 cc, year 1999 Loses Power Occasionally!!

[karena]

My beloved Golf has lost power a couple of times recently. Almost like the turbo has stopped. Both times on the way home! The following morning it starts, and power is restored. Any ideas what it could be? It is due for its service in about 300 miles.

[emm_11]

Hiya
I have the same problem with my golf and i have also had no replies!! I have found another site which gives some information about losing power if you look at the link below it may help you out
Emma
http://uk-mkivs.net/forums/thread/425656.aspx
ps if you do get to the bottom of it before i do let me know thankxxxx

[chris.fulton]

This is a problem thats been mentioned many times over and its one I've even had myself. My first advice to you is to get your car connected to Vag-Com or a diagnostics machine so that the fault code can be read and you'll have a much better idea of where the problem lies.

What is basically happening is that the car senses something is wrong and puts the engine into what we call "limp mode", which is basically like a low power, get you home while protecting the engine mode. Do a search on the forum for 'Limp Mode' and you'll find many more threads about this. The usual causes of this problem are:

1) Faulty MAF
2) Faulty N75 boost control valve
3) Boost leak due to split/dislodged turbo pipe
4) Sticking/Corroded turbo actuator arm
5) Turbo vanes clogged with soot

Until you get the diagnostics done, its hard to say which one of these it could be. In my case the turbo vanes were clogged and I had to get the turbo taken off and cleaned.

[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).