REV COUNTER problem - takes a while to start working

[Zayyan]

Got a rev counter problem which is that it sometimes (more often than not) doesn't come on when the engine is started but instead takes a while to wake up (has be anything from 2 seconds to 15 minutes so far).

Does anybody know what the problem is?

Car is a 1993 318i M40 if that matters.

Don't really want to change the clocks as it doesn't bother me that much but if it's an easy fix....

Thanks in advance

[Brianmoooore]

I would unplug and reconnect the C101 engine loom connector on the bulkhead a few times as a first try.

[Mops]

I would unplug and reconnect the C101 engine loom connector on the bulkhead a few times as a first try.

you may do the same with your ECU connector.

Get an alectrical contract cleaner and spray both those connectors well.

[Zayyan]

Thank you chaps, this appears to have worked

[Brianmoooore]

Thank you chaps, this appears to have worked

C101 doesn't seem to suffer corrosion problems generally, but the tacho signal seems to be exceptionally sensitive to the slightest poor connection here.