A&Q about 350Z
Q:
My gti's turbo has been cutting out recently resulting in a complete lack of power, however when the ignition is switched off and then on again (say at traffic lights) all is OK until the next time or maybe the next journey.
I had this investigated by a main dealer and was told it requires a new turbo at a cost of £1200!! The car is 4 years old and has done 74k miles (all by me). Is this a reasonable price or is there another alternative like a reconditioning kit?
Any help/advise would be greatly appreciated.
Thanks
Martin
A:
welcome to the forum firstly.
Has it been diagnosed as a faulty turbo? or does it just feel like that
If not, id recommend getting the Maf sensor checked. It can give the symptom youve described. This doesnt sound like a mechanical problem, but electronic, so could be charge boost controller perhaps?
I suspect the dealer could be touting for business in writting off the turbo?
A:
had this on one of ours it turned out to be a faulty relay
A:
Thanks guys,
Seraph - well, the main dealer diagnosed this as faulty, but my suspision is an intermittant electrical fault because it is always runs OK after the ignition is restarted and when working the turbo runs very well. Can I check the Maf sensor and charge boost controller without going back to the main dealer?
VW Jake - how can I check the relay and is it something I can change easily?
This brings me to the next question, does anyone know someone who can diagnosis this reliably in the North Herts area? Also I work in Paddington and therefore someone in the North London area would also be convenient .
I forgot to mention it is a Golf Mk4 1.9TDI GTI if this makes any difference
Thanks again
Martin
A:
Can I check the Maf sensor and charge boost controller without going back to the main dealer?
VW Jake - how can I check the relay and is it something I can change easily?
you can check it with vagcom, but obviously you need to find somone with it firstly who knows how to use it.
A specialist garage can do this for you.
The relay can be checked, but again, you need to know what youre doing. Its not hard to replace either, and shouldnt be too expensive. Its much less likely to be the relay than the other things imo.
A:
all the GT TDI's have been know to suffer broken turbos, but there are so many other things that will give the same faults
lets think about it, alls fine up until a point, then no boost (possibly after 2500RPM ish )
alls gone until the keys off then back on and alls back to normal
I'd put money on the 17964 charge control - negative deviation faults started
which means lack of boost being produced, likely to be leaking vacuum pipe, or a leak in one of the boost pipes. before changing a turbo which can be got rebuilt for about for less than half the quoted price
fault MAF will normally not boost at all, not go and come
A:
then no boost (possibly after 2500RPM ish )
harsh words!!
A:
oh but true
before the 2.3k mark the ECU ignored the boost state & doesn't freak out shutting all systems down
A:
oh ok, i thought you were saying theres no boost at all after 2.5k(assuming no probs)!
A:
if it has one of those vvt which i think some TDi's do, they get stuck and stick open, that cause's it to over boost, the engine ecu registers this as a fault and dumps the boost constant so not to over boost anymore, turning the igntion off and on resets the system and your away for a bit
had this fault on a passat 2 weeks ago and sure enough turned out to be a turbo
A:
^ yeah, all the mk4 pd tdi's have variable vane turbos iirc.
A:
quite a common fault too
A:
Follow up part 1.............
I have just recieved report from the main dealers in the post (their computer system was down last Friday) and it says although they couldn't get it to cut out there was "bad turbo lag". They carried out a fault finding test and found the "turbo over boosting" and recommended a new turbo.
Any suggestions?
Ps I've been driving the car this week keeping it below 2.5k and it hasn't cut out
A:
if it's over boosting theres a good chance it's the vanes sticking due to be sooted up
if it was mine while cold-slightly warm, get my had on the actuator, and a vacuum pipe took off the valve controlling it (behind air intake on bulkhead), suck on the pipe and move it up and down by hand
you should be able to move it from the pipe, then take it good run.
failing that I'd take the turbo off and strip the exhaust side and clean it (or take it to a turbo specialist)
A:
exactly the problem my bora 115pd had, had to have a new turbo as it was "over" boosting and then going into limp mode.