M3 REV COUNTER STOPPED WORKIN....?

Tue Dec 27, 2005 7:26 pm

JUST WONDERING IF ANYONE COULD TELL WHERE THE PICK UP FOR THE REV COUNTER IS ON MY M3 EVOII, JUST DIDN'T WORK THIS MORNING WHEN I STARTED IT, ANY HELP WOULD BR GREAT THANKS.

Tue Dec 27, 2005 8:43 pm

works off the ecu.

Karl

Wed Dec 28, 2005 11:17 am

karlp wrote:works off the ecu.

Karl

Are you sure?

Andrew

Wed Dec 28, 2005 12:21 pm

To be precise.

An engine speed sensor on the bellhousing feeds a signal to the ECU - the ECU then sends a signal to the rev counter.

Karl

Wed Dec 28, 2005 2:41 pm

Yup thats correct, but there is no direct feed from the ECU which you can see if one were to take a look at the ECU.

Andrew

Wed Dec 28, 2005 4:21 pm

On my diagrams pin 21 from the ecu goes to tachometer and fuel economy gauge.

karl

Wed Dec 28, 2005 6:29 pm

Could be re-chargeble cell in the cluster

Wed Dec 28, 2005 6:58 pm

Poor connection at pin 9 (black wire) of the C101 connector is often the cause of no tacho on an E30.
Don't have any M3 diagrams handy, but would expect this to be the same on a M3.

Thu Dec 29, 2005 9:05 am

Brian,

Is the C101 connector the ECU end or the clock end?

Cheers

Thu Dec 29, 2005 10:03 am

jpboost wrote:Brian,

Is the C101 connector the ECU end or the clock end?

Cheers

About half way between. It's the twenty something pin plug and socket clipped to the engine bulkhead just inboard of the fusebox, where the engine loom connects to the body looms.
I'm assuming that the M3 is similar to other E30s in this area.

Thu Dec 29, 2005 10:38 am

Yup its the same, but it has a few extra feeds.

Andrew

Thu Dec 29, 2005 12:55 pm

cheers.
my tacho hasn't worked since I got the car, keep meanign to get around to do some investigating. at least I now know where to start.
thanks again

Thu Dec 29, 2005 1:18 pm

howdy. My rev counter stopped working on my 325i and it turned out to be a short circuit in the boot which was down to the boot light. Every time i used to open my boot it used to blow a fuse, which runns the same circuit as the rev counter, so check your fuses. If it is blown, it could be down to a short circuit on one of your lights.. ie: glove box, interior or boot etc.. A BMW specialist in Gloucester found the fault on mine. Good Luck.

Fri Dec 30, 2005 6:06 pm

THANKS A MILLION LADS SHOULD BE ABLE TO GET IT SORTED FROM ALL YOUR INFO, THANKS AGAIN.

Fri Dec 30, 2005 6:29 pm

toptints wrote:howdy. My rev counter stopped working on my 325i and it turned out to be a short circuit in the boot which was down to the boot light. Every time i used to open my boot it used to blow a fuse, which runns the same circuit as the rev counter, so check your fuses. If it is blown, it could be down to a short circuit on one of your lights.. ie: glove box, interior or boot etc.. A BMW specialist in Gloucester found the fault on mine. Good Luck.

the renowned fuse 21

bastad thing!