Where has my TDI's Power gone?

[Danbag]

I have a 2000 (W) Golf 4 TDI, and during a long distance journey, my power just went! The only way I can explain the sensation would be if I ran into an 100mph headwind! The car now no longer wants to go above 65mph, cant go above 75mph without help from going down a hill, and hates going up them, where the speed will keep dropping off! I have to balance the throatal (at about 75%), to get anything out of the car, and when I put my foot down there is no engine note change, no higher pitch from the turbo, or air intake, nothing! Please, anyone got any ideas??

[veedub76]

Any fault codes on the dash?Have you taken it to a garage and had the VAG COM plugged in and the codes read?Any of the air intake pipes come loose from the turbo or intercooler?Check everything!

[Danbag]

Any fault codes on the dash?Have you taken it to a garage and had the VAG COM plugged in and the codes read?Any of the air intake pipes come loose from the turbo or intercooler?Check everything!

Nothing flagged up on the dash board! Not had chance to put it in garage yet, is it worthy of that on face value, you think??

Took the air filter off this afternoon and run cleaner/oil through it, as instructed. Vacuum hose was as its always been. Am goin spray the diesel bob carbon blaster cleaner directly through the air intake before refitting, to see if its something clogging the turbo operation. Good/Bad idea?

Is it a problem that may sound familar to you/anyone? It is mighty annoying!!

Thanks in advance

[helen]

keep on reading other power loss threads,thats a common vw problem

[veedub76]

Nothing flagged up on the dash board! Not had chance to put it in garage yet, is it worthy of that on face value, you think??

Took the air filter off this afternoon and run cleaner/oil through it, as instructed. Vacuum hose was as its always been. Am goin spray the diesel bob carbon blaster cleaner directly through the air intake before refitting, to see if its something clogging the turbo operation. Good/Bad idea?

Is it a problem that may sound familar to you/anyone? It is mighty annoying!!

Thanks in advance

Take it to a garage as it sounds like your Turbo may not be working.My turbo is audible at most speeds and,if you have experienced power loss like you say then get it looked at.How many miles has your Golf covered and has it Full service history?

[Danbag]

It has done about 140,000 (she's getting on a bit!). The turbo is audible but there is no note change, it is a constant. Only dealership stamps, doesnt tell you what work its had done though.

So, an update! The cleaning of the air filter and carbon blaster/cleaner didnt fix the problem.

I have noticed that the power loss does not manifest itself until you hit about 3000rpm. I read in other power loss posts (thanks, helen), that you can 'reset', the problem by switching the engine off then back on...so I did, the power was restored, but then cut out at around 2600rpm, where the car continues to accelerate without ANY urgency in the slightest

Surely if switching the ignition off effects the problem, and it is not from when the engine is first turned on, it cant be something mechanical failing?? - can it??

for eg. Is there anything that acuates at around these engine speeds that would cause a powerloss if faulty?

[besian]

respect you gt tdi

try when you loose the power to switch off the engine and switch on. if the power comes back than your turbo boost valve is gone

[veedub76]

Well it could be your actuator or EGR valve sooted up or the MAF.My GT TDI hits boost around 2000 rpm then tails off around 3000rpm it has urgency but once peak power has been reached it does tail off as diesel's just don't rev out like petrol's.Maybe you ned to get it hooked up to a VAG COM and see if the ECU has any faults logged.

[Golf_TDI-150]

hi

my mate had this problem on his tdi, the turbo was working but not winding up. it turrned out to be the air flow sensor on the the air intake pipe

hope this helps

[Danbag]

Forgive me now as I am going to reply to everyone at once;

If the turbo boost valve/actuator has failed, would it log a fault within the ECU?

I think I have ruled out the MAF as surely the problem would be permanent? - I have had a problem with it in the past, and have had problem with it in the past and had no problem with acceleration (I think), just top speed.

Coincidently, what is typically the shelf life of a MAF? - How many miles does it last for example?

If there is a problem with the EGR, wouldn’t there be other signs to?

I think one thing is universal, VAG COM may hold the answer, ill get it plugged in a soon as possible.

If anyone thinks of owt else in the meantime would be grateful