Mk3 Golf TDI throttle position sensor

[j_coupland]

Hi all

I need a new throttle position sensor for my Mk3 Golf TDI. Sometimes there is a delay between pushing the throttle and the engine doing anything, this can be quite dangerous when trying to pull away at roundabouts or junctions because the car has a mind of it's own! :(

A recent ECU check at a local VW garage showed up either a faulty throttle position sensor or some kind of faulty relay in the alternator, the TPS being the most likely problem.

They couldn't get a price for the sensor when I was there. Can anyone give me a rough price for one and/or tell me where I could get one?

Ta
John

[mojogoes]

J...........what are your full symptoms and i take it you had to pay for the *******ship to have no idea what was wrong with your car , what year is your mk3 tdi if its the older model like mine is it has a wastgated turbo and if its late 95 on it will have a vnt turbo which is operated via vacum,

And a good tip for everyone who does have a faulty maf sensor or a suspected bad maf b4 you take it to the dealer you need to unplug the maf sensor and drive around with it in this condition this does 2 things the 1st is if the car seems faster at the bottom end then this telling you the maf is dying and the 2nd this will throw a mill light then just b4 you take it in to the deal hook the maf back up...........so when they hook it up to the vag-com this will show up as a boost fault.

If this is not done there is no way there vag-com system will pick up a dying maf sensor , another question J is does your motor smoke more than usual or feel it has no power or low power once on the move.

[j_coupland]

Hi mojogoes. Sorry I just got back from a weekend away.

It's a late 95 Golf with the 1Z TDI engine. I haven't had the warning light at all. The symptoms are sometimes when it's idling and you push the gas pedal nothing happens until a 1 second delay then the engine revs up. Also sometimes if you try to pull away fast from roundabouts the car won't move and then it will move even if i've taken my foot off the gas pedal which is dangerous in rush hour traffic! Any ideas?

Oh and theres no more smoke than normal and the car does shift well throughout the whole gearbox.

[mojogoes]

Its possible that its the sensor , has the car had a timing belt put on quite recently if so this can make the car respond in the way you say by making the timing retarded.

Or even a blocked or partly blocked fuel filter , or even if you don't put the filter on properly making shaw the rubber seal is sealing as it should.

[j_coupland]

The timing belt was done back at 60000 miles and won't be due again for another 2500 miles. I've not had the fuel filter looked at yet but I'll have a look. Could there be anything wrong with the turbo at all?

[mojogoes]

Can you hear any whoooooshing or hissssssing sounds at all!!, it may be because you have a boost pipe leak either at the intercooler pipes which go from the turbo through the ic then on to the inlet manifold or its more likely its the small vacum pipe which go to and from the n75 valve which you can see on the left hand side of the wing when you open the bonnet across from the air mass meter.

This valve should have a red , black , and blue hoses attached to it , they have probably not been changed....ever so i would do so , its more likely to be these above the larger ic pipes because of the lack of smoke your saying the car produces.

J a quick test you can do is disconnect the air mass meter and go for a drive and if the car picks up better than it did on the bottom end , its your mass air meter/sensor , or n75 valve............report your findings when you've done this .

[j_coupland]

I unplugged the MAF sensor last night and the car felt very sluggish, like the turbo wasn't kicking in. Obviously it was OK when I reconnected it. Can't hear any strange sounds coming from the turbo apart from it spooling up. Hope this helps.

[mojogoes]

Its going to be a processes of elimination what about the n75 valve next , if you open the bonnet when the motor is still running can you here a ticking sound or not.

[j_coupland]

I can hear some sort of ticking sound when its running, difficult to hear because of the racket the engine makes!

[mojogoes]

If so this means the n75 valve is ok , try this one disconnect the positive cable from the battery for 10/15 minutes then reconnect and then go out for a spin.

And another thing you could try is have someone spray a can of 10K diesel cleaner into the intake , but make shaw you spray ater the maf sensor and have someone rev the engine to 2000rpm while your doing it.

Can you remember if this prob started after a bout of spirited driving , and the last one is do you know someone with the same car so you can change the maf sensor to 100% check it out.

[j_coupland]

Disconnected the battery like you said and it seems to have made the throttle response a bit better but I'll keep you posted.

I'll try the 10k stuff soon. The car always had the problem even before I bought it and over the past year i've got used to it. But now it's starting to annoy me! I don't know anyone else who has the same car to try the MAF sensor but as I said i'll keep you posted. Thanks!

[mojogoes]

Who had the car b4 you bought it it wasn't your mother or older sister was it in that case it probably needs an Italian tune up!!! , and if it has been in the family or belonged to a friend for some time and you know of it not having a maf in the last 3/5 years if i were you i would invest in one..........they only last around 3 years max and deteriorate so slowly and by a very small %% you never notice them going bad.

[j_coupland]

Just done the 10K Boost, man that stuff is good! It didn't solve the throttle delay problem but it did make the throttle response sharper and quietened the engine down a bit, however I just noticed a faulty wheel bearing somewhere, damn...!

The car was used as a company car b4 but I got FSH and loads of receipts so I'll look for a new MAF sensor in the pile. If not thats the next job for the car. I'll keep you posted, thanks!