Help required: VAG 2.0 engine questions.

Have you asked on vwvortex?

1. Usually flat spots in the rev range. MAF problems are very common on VAG engines. If you are having running problems and you suspect the maf, best method of checking is to disconnect the maf. If the engine running problems are better, the MAF is most likely goosed. If they continue, the maf is not at fault.

The *BEST* resource on the web for mk4 Golf's and Bora's is the UK-MKIV.net site. Have a look at the link below.....

Alternatively, do you know anyone with vag-com? This is the only 100% guaranteed way of diagnosing a faulty maf. You need to log the maf results at full throttle over the entire rev range and check the peak air intake results. On a petrol engined car, the peak air should be approx 80% of the car's bhp. So on your 2.0, you need to be looking for a figure of 92.

Nope, I didn't know about them. But I do now. Cheers.

Well, that's exactly what I've got. I did a bit of fumbling about the net last night which put the idea of a knackered MAF in my head, but in the great tradition of stupid question vs. stupid mistake, I thought I'd ask first.

I read somewhere that dirty electrical connectors may also be a problem (as well as a dirty MAF), so I'll check this tonight. If that's fruitless, then I'll investigate the actual sensor.

That's brilliant, thanks mate.

I think the garage I use has it, I'll get him to have a look if my Columbo-ing doesn't pan out.

Thanks again.

Also, whilst I'm thinking, can I ask what the potential drawbacks are to running the car without the MAF connected? (I don't plan to do this, I'm just curious)

Cheers.

The ECU will just use "default" parameters to control fuelling as it is getting no signal from the MAF. You could always try cleaning the maf with electrical contact cleaner, as an initial step. Take out the two security bits that secure the maf to the housing. Pull out, and spray electrical contact cleaner onto the wire. This has been known to help short term.

Would have a negative effect on the fuel economy and/or power developed?

This was my plan!

Thanks again.

Yup. The fuelling will be 'guessed' and the timing will be wound right back, causing a loss of power and increased fuel consumption. Your catalytic convertor probably won't appreciate it over the long term, either.