**UPDATE** Turbo K.O.'d???

[Ivor Mk4 Turbo]

A strange one this.  I have recently seemed to pick up a bit of an intermittant fault.  The turbo seems to have spells where it doesn't want to kick in.  There are no warning lights, no strange noises, no unexplained smoke, no strange smells.  When this is happening, the car idles fine, but the revs seem to take forever to climb (does it smoothly, though).  There's just no kick from the turbo whatsoever. :sad:  Clutch isn't slipping, either.

Then the next journey and/or next day, it will be back to normal again.  It's been alright for the last 4 days or so, but did it again last night.

I'm fearing the turbo could be on the way out!

If anybody has ever suffered anything similar, or got any ideas on what to do, I'd be extremely grateful.

Thanks,

Ivor.

[topher]

i wouldnt expect it to be intermittent if the turbo was dead, boost solenoid maybe... need to get it on vagcom really or you could be looking for the fault for ages.

[New Duncan]

Just thinking aloud -

Have you checked the pipework for leaks, also do you have any oil in the pipework from crank case presure ? Oil could be plugging the leaks temporarily and then, next day, it's moved out of the split.

I do think as Topher, a diagnostics check is the fastest route to a guaranteed fix.

I dont think it''s your turbo, it would have been slowing reducing it's effectiveness over a long period.

I'm sorry, But I've not owned the turbo for more than 4.5 months, and my previous one was a Saab "Hard" Garett one in the Saab 900 st.16 es

[Ivor Mk4 Turbo]

First of all, thanks for the replies, guys.

I've finally had the motor on the diagnostics, & it has (according to the readout) turned out to be the 'Hall Sender'.  Apparently, it's a 'cambelt off' job to change, can anyone please clarify.

Thanks, again.

[New Duncan]

Well Ivor, this is the best explanation I can give. I'm not a VW master technician, as you know.

It's the crankshaft sensor, I'm pretty sure of that. In this guise, it will be vital to timing in a vehicle will ECU ignition or to starting the operation for the turbo.

I'm surprised that the engine still runs sweet. The "hall effect" in electronics, is the ability of  a circuit capable of counting.

Perhaps it's the revolutions counted before the turbo comes in ?

Here is a link to crank shaft sensors in China. When you buy a VW cambelt tensioner (a pully bearing actually) and about 4 times the price of the cambelt, it is made in Japan ! Who knows - Porche parts may be forged in China, Korea or Japan ??


Link to a similar or the same product

http://skk.en.alibaba.com/product/50127339/50584545/Auto_Electrical_System_Parts/Speed___Pressure_Sensors.html

[GOLF_STU]

i have exactly the same problem with mine and its comin down to the re-map that was done before i brought it. when it does it if you turn the ignition off then back on again it re-sets the system and it will work fine.

[Ivor Mk4 Turbo]

A pal of mine has suggested the following:-

"Its an engine speed / reference signal.

Sounds like our equivalent crank or cam pos sensor!?

Its part of the knock circuit too so your prob experiencing ignition retard and boost limitation, which would make sense."

STU:  Where was your car re-mapped, do you know?

ps Mine's back at the stage where it doesn't return to normal after switching off!  Saying that, though, it did return for a day, but that was after the car was left standing for a week.

DUNCAN:  Yes, I'm surprised that it's running ok, too - Quite bizarre, really.  (Although I sure am missing that 'surge' from the turbo, ATM!

[Say bye bye]

If it is the cam postion sensor, that costs roughly 80-85 from dealers 
If your not sure where it is, take the engine cover off, unclip the cambelt cover on the left, just hold it back you will see the sensor next to the cam belt its metal round and about the size of the palm of your hand. Its held on by 2 bolts ofcourse the wire connections... VERY easy to take off just mind you dont loose the bolts!!!
Im gettting cam belt postition sensor error on my car BUT its showing no loss in performance no hesitation nothing!!! 
What error code were you getting???

[New Duncan]

Well, I've got the sensor prognosis right. Calling it a Hall sensor gave me the clue to a circuit capable of counting - as you said Ivor, a reference for crank revolutions.

Ivor, there is only one thing for it.  Change the sensor, do you need a new cam belt or water pump ? They are all behind the cover, but to get it off, and clear of the work area, you have to undo the  right engine mounting and jack it up a little to give clearance.

My independant technician in South Oxfordshire will do performance cars. Does my BM,  I always see something quick or sweet in his workshop. If not, go to someone who is good and actually KNOWS.

Good luck.

[GOLF_STU]

A pal of mine has suggested the following:-

"Its an engine speed / reference signal.

Sounds like our equivalent crank or cam pos sensor!?

Its part of the knock circuit too so your prob experiencing ignition retard and boost limitation, which would make sense."

STU: Where was your car re-mapped, do you know?

ps Mine's back at the stage where it doesn't return to normal after switching off! Saying that, though, it did return for a day, but that was after the car was left standing for a week.

DUNCAN: Yes, I'm surprised that it's running ok, too - Quite bizarre, really. (Although I sure am missing that 'surge' from the turbo, ATM!

not sure mate it was already done before i brought the car but its goin into jabba sport soon to have it re-done as im not sure as to weather the re-map is causing my problems however i took it apart to-day and have found the breather pipe off the rocker cover has split. im replacing it tomorrow so will keep you updated as to weather it makes any difference