zomo tech

air mass

Wednesday, 10. 26. 2005  –  Category: all, vague

The turbo on my VW Golf 1.9Tdi had become disappointingly non-functional. I could hear the exciting whizzing from the device as it spun up, but there was no boost. For a heavy car like a mark 4 Golf, this makes driving a pain, both around town and on long motorway inclines.

Getting the garage (who are cool and have never ripped me off) to diagnose the fault would cost at least two hour’s labour, plus a callout fee for the bloke with the expensive VW diagnostic computer. Actually removing the turbo unit from the engine would cost north of £300.

Thankfully, there are two (relatively) cheap and accessible components in the setup, the solenoid which tells the wastegate to operate, and the air mass sensor (aka MAF) that tells the car’s brain how much air there is to compress. Both of these aren’t in the turbo unit itself, but located just beneath the bonnet. I picked one, the latter, and replaced it for the small fee of £60 + VAT. The MAF sits immediately behind the air filter on the air intake pipe. Two Philips screws and a big clip later and the new part was in.

The fix was obviously working within seconds of driving – it’s like having an engine several times larger. Woo!

Technical info about MAF here.

A forum of VW turbo woe here.