Low Power at Low Revs

[drbass]

Hi everyone,

Haven't been on the forum for quite some time but thought I'd seek some advice with an engine-related issue.

Car: Eos MY2009, 103 kW CR turbo diesel (manual 6 speed gearbox), 41,000 km.

Issue: you probably remember the good old days of carbies and chokes. If you left the choke out once the engine warmed up and you put your foot down the engine would not rev (I'm talking petrol engine) or develop any kind of power until a certain rev range was reached.

That's exactly how my wife's beloved Eos is behaving. It kind of putt-putts along until the revs reach about 2,200, and that's when power comes in - very abruptly. This behaviour started from one day to the next.

Tried "Italian tune-up" without success.

Took it to the local dealer today for a diagnostic, and they were unable to find any fault. They got me to drive a Tiguan with the same drive train to convince me that it's behaving exactly the same, and that our Eos is within specs. Sorry, I had to say, this feels like two completely different drivetrains. To paraphrase the current Golf commercial: "Drives nothing like my Eos".

So no joy from the official dealer. BUT: it's not right, and that was not acknowledged.

Thought I might take it to an independent VW mechanic and see what they have to say. Probably now much more.

So: Any ideas from anyone? It's not only annoying but actually potentially dangerous. Trying to pull out into traffic you really don't want this to happen.

Looking forward to your reply.

Regards,
Michael

[nightphotographer]

Is it just turbo lag? Some TDI's get it worse than others - my old stock 2.0TDI (168BHP) SEAT Leon had major turbo lag - my 1.9TDI MK1 Fabia VRS had barely any due to a custom code and LWFW.

[Lito]

is it a vnt turbo, maybe the vanes (if that's what they're called) have seized?

[kaanage]

Possibly the vanes in the turbo are stuck in the open position - either due to carbon buildup or a vacuum leak in the actuator circuit.

This would greatly delay spooling up of the turbo.

Edit - Lito beat me to it...

[nightphotographer]

IMO it wouldn't be turbo related if there's a surge of power at turbo spoil time - i.e 2200 rpm? If overall it's dropped huge amount of power at all revs then it would be?

[kaanage]

No. The turbo action is not linear with exhaust flow.

Watch early '80s F1 to see how turbos come in hard at a certain RPM.

[getjet]

Have you scanned for codes?

I too had low power down low and some hesitation etc. turned out my egr system was causing it.

[gldgti]

as kaanage said, turbo actuator problem seems very likely.

if it is a mechanical fault like leaky vacuum lines, scan wont pick it up. If carbon buildup has caused the vanes to stop closing fully, that also will not show up with a scan.

You will need to take it to someone who both knows what they are looking at, what they are doing AND is happy to get their hands dirty in order to confirm

nightphotographer - the stock VNT fitment is such that they will make full boost with the vanes nearly fully open from 2500rpm onwards. They really only close up at very low rpm to aid the spool. A properly functioning standard TDI with VNT will make full boost at less than 1500rpm.

[drbass]

as kaanage said, turbo actuator problem seems very likely.

if it is a mechanical fault like leaky vacuum lines, scan wont pick it up. If carbon buildup has caused the vanes to stop closing fully, that also will not show up with a scan.

You will need to take it to someone who both knows what they are looking at, what they are doing AND is happy to get their hands dirty in order to confirm

Thank you, gldgti,

The issue now is to find such a person . The dealer I went to (and this probably applies to most) is hiding behind the "diagnostic does not find a fault, there's nothing wrong, there's nothing we can do" wall. Not an option.

Does anyone know of a place with actual mechanical knowledge in Melbourne's north-east? I thought of giving Volkswerke a try - any comments on that?

Thank you again to all.

Regards,
Michael

[manol]

Thank you, gldgti,

The issue now is to find such a person . The dealer I went to (and this probably applies to most) is hiding behind the "diagnostic does not find a fault, there's nothing wrong, there's nothing we can do" wall. Not an option.

Does anyone know of a place with actual mechanical knowledge in Melbourne's north-east? I thought of giving Volkswerke a try - any comments on that?

Thank you again to all.

Regards,
Michael

Volkwerke and the guys that work there are fantastic. Highly recommended.

[drbass]

Thanks, manol,

Went in yesterday and made an appointment - I did get the impression of a very knowledgeable crew!!

Regards,
Michael