Tach issues on 318iS

[MR 325]

I've been helping a friend work on his 318iS. One of the problems with the car was a non functioning tach. Since his odometer was dead anyway, he picked up a working cluster from a local R3V member. I saw the tach 100% working in the seller's car so I know it's good.

Now that the cluster is installed in to the car the tach is not functional. I had another M42 coding chip laying around so swapped that out with no success. Also checked the fuses and found nothing wrong... What could be the issue?

[dnguyen1963]

I've been helping a friend work on his 318iS. One of the problems with the car was a non functioning tach. Since his odometer was dead anyway, he picked up a working cluster from a local R3V member. I saw the tach 100% working in the seller's car so I know it's good.

Now that the cluster is installed in to the car the tach is not functional. I had another M42 coding chip laying around so swapped that out with no success. Also checked the fuses and found nothing wrong... What could be the issue?

If you have a good working cluster and SI board then I think the board is not receiving signal from the engine. Check sensor and cable.

[nando]

there's no "sensor"

but there is a wire, it's black, that sends the engine RPM signal from the ECU to the cluster. it passes through the C101, you could test for it there.

[James Crivellone]

Have you REALLY checked the fuses? IE with a multimeter. I had a tricky one where the fuse looked fine, and even passed some voltage but was barely connected. Replaced and bingo tach

[MR 325]

I did not have a voltmeter on hand but I replaced the fuse with two others and no luck.