Erratic rev counter - Audi 80

[msond]

The rev counter on my Audi 80 2.0 E (M/95) is erratic. Whilst driving, sometimes it flickers across the rev range and somtimes it does not work (this also causes the oil light to come on - checked oil level - OK).

There is no cable, so how does the rev counter work and what may be causing the problem? :1zhelp:

Thanks for any help.

[jp_paul]

The tacho works by electromagnetic induction. A rotating magnet causes an electric current pulse. This is transmitted by wires to the tacho, which is in fact a pulse counter. I'm not 100% sure on the location for the 2.0, but the 1.8 has an electrical connector block attached to the gearbox, just above the n/s inner cv joint. There should be 2 that look identical in the vicinity. One is for the tacho, the other for the speedometer. I recommend thoroughly cleaning both of these with an aerosol cleaner. Bad connections here are to blame for 99% of misreading instruments!

[msond]

Thanks for the tip. I'll try that. At the moment it seems to be working fine again.