Cluster questions!

[JakeP]

Car: 1991 318i 4 door, bought it about 6 months ago with a non working odometer at 153k.

Pulled cluster to replace a bunch of light bulbs, so I know how to do that fairly easily. All the fuses appear to be intact and working. I'm pretty decent at electrical and wrenching, so I can do any tests that would help you guys.

My problems:

A) My speedo works well, but my odometer doesn't read. Bad odo gears?
Since the speedo works, I assume it must be gears.

B) My tach doesn't work. Bad gauge? bad pickup? Where the hell does a 318 pick up tach signal?

C) My econometer (MPG gauge) doesn't work. Bad gauge? How does this thing even work? (my dad and I were having a discussion on it)


Bad SI batterys? Bad Gauges? Bad pickups?... any Ideas?


Searched some and found these:

http://www.r3vlimited.com/board/showthread.php?t=147797&highlight=gauge

http://www.r3vlimited.com/board/showthread.php?t=198932&highlight=gauge

[nando]

a) yes, bad gears.

b) it gets the signal from the ECU. SI board, or possibly a fuse.

c) it gets a signal from the ECU, and uses your speed VS fuel rate to calculate MPG. The SI board does this, so dead batteries can cause it to go out.

[JakeP]

So, replace gears, physically check relevant (or all) fuses for continuity, possibly replace SI batteries?

OR

Replace whole cluster for a new one?

[AundrezIS]

I'm having the same problem. I just swapped the cluster for a new one and the tach and odo still don't work. :(

[nando]

So, replace gears, physically check relevant (or all) fuses for continuity, possibly replace SI batteries?

OR

Replace whole cluster for a new one?

the gears aren't expensive. you could get a new cluster, but it could have the same (or more) issues.

Check the voltage on the batteries for the SI board. They should be the lithium batteries - if they are under 3v, replace (with the same type of lithium batteries).

fuses of course, are simple.

[JakeP]

Gracias, nando. I'll test all the fuses and check voltage on the batteries, then report back tonight or tomorrow. I know Matt sells the gears, I just gotta get some from him.

[blindwOw]

Since you guys are talking about odometers, I have a question.

Is it possible to swap a VDO odometer into a Motometer cluster?

[AndrewBird]

The way to tell if clusters are compatible is to look at the service indicator lights. If both clusters have the same number of lights, they are compatible, whether it be Motometer or VDO.