Car Topic - Diesel Polo power loss

[garth]

Hi

My old man has a VW Polo Diesel (TDI Sport)

When you drive it it will lose power - like the turbo isn't working. This isn't the case as it can still be heard whistling. When you turn the ignition off and restart it, it will recover, and maybe be fine for 10 miles and lose power again, or be fine for the rest of the journey - there is no obvious trigger.

The MAF (air regulator?) has been replaced - it wasn't that, and the air, fuel filters have been replaced also. It's not high mileage and is 2002.

Anyone help?
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[Davo]

Sounds like my old mondeo, every so often the ECU would put itself into "get you home" mode, which is a safe setting.

When it happened you could barely get the car over 30 mph. Turned out to be a grommet in the air intake system was causing the air mass indicator to mis-read.

Will be worth getting the car on a diagnostics computer, as they should be able to read the fault code off the ECU. How old is the car?

[Nb]

Like Davo says, you need to get the car on a suitable diagnostic machine and see what code or codes it has stored. Dont spend any more money changing stuff until the ecu has been read out for errors. Take it to a reputable garage, not some tyre and exhaust place.
Im going to guess that the turbo vanes are sticking and that when they do it starts to overboost hence the ecu going into limp home mode, once you turn the car off it thinks its fine again until the vanes stick again and it goes back into limp home mode.
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[Faldo]

As said above, you need it to be diagnosed properly. It could be anything.

When you replaced the MAF, did you use a genuine Bosch one, or an aftermarket part ? I used to sell cheapo ones, but gave up on them a couple of years ago because about 40% came back under warranty.

Obviously something electrical due to it being OK after being turned off/on, so a quick spell on a diagnotics computer will pinpoint what's needed very quickly.
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[rotax81]

use the following forum. they sorted mine out.
you have people on there from ross-tech who do the VAG diagnostic stuff. totally TDI nuts on there... american based but very helpfull.


https://www.tdiclub.com/

have you tried driving it with the fuel cap off?
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[Cigaro]

It could be any sensor playing up, not nessecarily the MAF.

[NSR Mick]

Get the codes read. If I where nearer I'd do it for you.
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[Phil_G]

Ok, not a Polo, but our 2003 Transit did this and it turned out to be the EGR valve. We had it cleaned out, and its been mint for the last 30,000 miles.

Let us know the outcome

Phil
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