Turbo had innotec + fixed-back to limping!!

[Mike McKinstry]

Hi All,
After long saga of limping under load and especially when pulling when cold and a 17965 overboost pos.deviation I did innotec clean the t/bo 3 weeks ago which gave immediate 2 weeks of improvement.
Unfortunately back to limping again and I am now wondering ;
a)Why would this turbo if successfully cleaned have got coked up so quickly again(EGR has been disconnected).oil was changed as is every 6 mths with Vw quantum and fuel treatment and fuel filter changed at time of treatment ?
b)Before purchasing a new/recon turbo are there any turbo specialists out there who would test on car and give definitive yes/no to the turbo being at fault.
c)I a recon better than new on a 160k 51 plate PD.

Really want this sorted now!!

[martin1810]

Turbo cleaner often doesn't work long term. The turbo needs to be taken off and cleaned properly. Lots of info on the web about how to dismantle and clean. Or send it to a turbo specialist for cleaning.

[Mike McKinstry]

Thanks Martin.I am resigned to the fact I will need to do this but not sure if cleaning will fix orig turbo or if it needs more work?Also still concerned why this would coke up so quickly so reluctant to put on a clean turbo or recon/new before finding out whats up or money down the drain.
Can be smokey on startup which I put down to rings but not using any oil so would a dodgy glow plug cause smoke on cold start up and contribute to coke in turbo?
Now i am thinking sometimes at idle will get quite intoxicating fuelly smell ?

Anybody comments on b and c of original post.

Maybe just time to get rid!
Mike

[martin1810]

I don't think chemical cleaners really work. They might remove light surface carbon dust but the thick gunge that builds up just doesn't come off. Carbon build up on the vanes is normal, not a sign of engine problems.

[Mike McKinstry]

Thanks-that sounds very reassuring however what has prompted me to this line of thought is all the turbo specialists websites who insist there must be something wrong and that the turbo would not coke up unless there is an issue?.
Also do you think any of the turbo boys can test on car before I have to part with cash?

At mo;
Essex turbos £464 for recon
GSF £729+VAt-new
Eurocarparts £807 -new
My local factor £564 recon/£680 new
Turbo Technics -£200 to clean
Midland turbos-£212 to clean

Have also read you are probably best NOT to put a new turbo on a worn engine-assuming 160k is possibly in this category although I suppose hard to say depends on service etc which has been done every six months.?

I suppose when they claen they would inspect for any other issues??

Mike

[passat 130 tdi]

been there got the t-shirt , bla bla bla - as martin knows as i pestered him all day for a week for this very problem - mine turned out to be the thrust sensor ( map ) , if you can get hold of a mate or similar with a passat , swap it out and try it - it cured mine instantly.

i did however , blow 10k boost into it , innotec cleaned the t/bo , changed all vac lines , changed the n75 . last straw was the map sensor.



WHY would a new turbo on an aging engine cause problems ??? surely a recon is meant to be as good as new - my best quote was £850 for new fitted. new map £49 well chuffed.

[Mike McKinstry]

Had MAP(charge sensor),N75,MAF all replaced but clue is turbo was fact car gave 2 weeks no trouble after cleaning!
Now back to limp every slip road and even flats.

[passat 130 tdi]

mine gave me 2 weeks of pain free too after the 10k boost then it just got worse , when it goes limp , with engine running , check position of actuator arm.

[martin1810]

Mike...A lot of the talk about turbo's is confusing because people confuse the turbo's. It would be unusual for a normal (non vnt) turbo to coke up enough to stop working and it would indicate an engine fault. VNT turbos are different. The turbo doesn't coke up, the variable vane actuator ring inside, cokes up. When this happens the vanes on the blower get stuck. They always get stuck at the full open (max pressure) position. This means that at full thrust the ecu is happy as the pressure is meant to be at max. As soon as the revs start to drop, the pressure doesn't. The ecu see's this as overboost and goes into limp. It's very likely that midland turbo etc can just clean the vnt mechanism and send it back. The turbo its self probably has nothing wrong withit. Putting a new or recon turbo on an old engine is not a problem, the engine won't even know.
Have a look at http://www.britishvegoil.co.uk/smallengine/vnt.html

[PeteK]

I recently bought some Forte advanced diesel fuel treatment for my Passat. Whilst doing some research on this, I found a thread on a Golf forum in which it was claimed that using this had cured the sticking VNT rings after suffering the same issues as yourself. They basically added the treatment in quite a high concentration (less than half a tank as opposed to a full tank) and then gave the engine an Italian tune up!

Personally I was a bit sceptical about how this could work, but at only £10 a bottle on Ebay it may be worth a try.

Edit, just found the link here. Makes quite interesting reading... http://tinyurl.com/y9kknl9

(I hope it's ok to link to another Forum, apologies if it is not!)