E30 Zone

i have noticed that my battery is draining a bit to often even a new batt doent slove the prob. after swithing the engine off the rev counter needle jumps up to the 1000rpm mark. think it might be a bad earth. ANY IDEAS

Mine does the same!!! I'm not alone!!! I thought it was just something i could never put my finger on.

Earth point for the cluster (and loads of other things) is on a stud above the middle of the glove box, but I doubt if it'll help.
Odd quirks with the tacho seem to be a characteristic of the later type SI board with lithium batteries.
First thing to check is the voltage across the battery terminals with the engine running. Should be just above 14 volts.
Next, switch the meter to a current range, take off the battery earth clamp and measure the current that flows when you connect the meter across the gap. Around 30mA - 50mA is normal, depending on what equipment is fitted. Anything above 80mA - 90mA needs investigating.
Make sure you have the keys/open a window before reconnecting the battery, as a long forgotten alarm may lock the doors!

thanks i try that