E30 rev counter and oil service light

[oldnbold]

Hi All,

Can any expert help please?

1. The combined rev counter and manifold depression gauge instrument has just died. Put it away one evening, all normal then came back next day and instrument quite dead. Must be electrical but no loose wire that I can see and all the fuses are intact. Any ideas?

2. The oil service warning light came on. Took it to the garage, they gave it a full service and reset everything but - the light still comes on. Aargh!!

Thanks in advance for any ideas

[Rtaylor2208]

1. For the first one I have no idea what a manifold depression gauge is, do you mean the enonometer?

For the second, you can reset the servie lights by bridging two connections in the diagnostic cap see here:

http://www.e30zone.net/modules.php?name ... et+service

[Grrrmachine]

The thing you're calling a "manifold depression gauge" is not that. It's an econometer, but it's a lot more complex than a hose pipe from the rocker cover, like Fiats use. It displays real-time fuel-rate usage based on injector pulse duration, and is fed from ECU data.

All of your problems are linked, and are symptomatic of the SI Batteries; the power cells built in to the dash cluster. They're a common problem on E30s, and you can read more about them here:

http://www.e30zone.net/e30zonewiki/inde ... _Batteries

[Brianmoooore]

Manifold depression gauge!!!!!!!!!!!!!! You're obviously fairly new to BMW! BMW never use a simple system when a complicated one will do!
Anyway, SI board batteries are almost certainly your problem.

[oldnbold]

To Rtaylor2208, Grrmachine and Brianmoooore - very many thanks and apologies for not coming back immediately - non-car problems took precedence for a bit and I didn't check the forum. Anyway, help much appreciated. What a great facility this forum is.

[jonny323i]

ive got a couple of complete clusters which have the service boards still in them pm me if your interested