Tach Not Working!!

[chiefcorey]

My dad has a lowered '97 328is. Over 207,000 KM's on it.

His problem: The Tach goes to 2,000 RPM then stops. Any idea what could be causing this, and if there is a fix?

Only other thing is that sometimes if he punches it hard, it will jump up to a high RPM, but he doesn't really drive like that normally.

Thanks!

[jase7678]

My car does the same. I was hoping it was a sender that was at fault, but sadly it's my tacho. I deduced this by running the test detailed here:

http://home.att.net/~ebaines/e36_instruments.htm

The last test is a sweep of all the gauges - my tacho jumped rather than swept. If yours sweeps, it's probably a sender.

Hope this helps.

Jason.

[chiefcorey]

Thanks, I'll try that out and see what happens. Any idea what it costs to replace a sender or a tach?

[jase7678]

None at all. I don't think the tacho can be isolated. I base this on reading this forum and not knowledge however as most posts point towards a new binnacle which is around $300. I put up with the jumping :)

Jason.

[gringo]

My dad just bought a 1999 328ic. It has the same problem -- tach stays at 2500 rpm unless you go above 5000 rpm, in which case it drops to 0. I believe that the tachs have two perpendicular coils that determine the magnetic field that the needle will align with. My guess is that the fields are pointed (1) 45 degrees left of up, and (2) 45 degrees right of up. The coil that drives field (1) is working, but the coil that drives field (2) is dead. The solution then is to replace the tach. I bet that any gauge will work, we just need to wire it correctly. Taking the dash apart is hard part.

Has any removed thier instrument cluster? Is it difficult? How long does it take?

[RahgBag]

Removing the cluster is simple, but it's a pain. Look above the glass and there are two screws holding the cluster in place. Unscrew these, and push on the bottom of the glass until it starts to pop out. Mine took quite a bit of force. There are 3 plugs on the back. They are kind of tricky, you have to grab the slider portion in the middle of the plgu and pull on the slider, not the plug itself to get it to slide out. You'll figure it out. The wires are really short and if you have big hands like me it's hard to do this. You'll need a long, thin torx driver to remove the screws. I don't remember the size, but auto zone had the driver for pretty cheap. Then the cluster comes in half and you can get to the gauges. There's a DIY in this thread:
http://forums.bimmerforums.com/forum/showthread.php?t=535358