[M3] Tach/Electrical Problems

["Tarun Kundhi" <julie-tarun@xxxxxxxxx>]

I just had my 91 M3 in the shop to get it prepped for my first track event.
After the work was completed the car was washed, including the engine
compartment.  When I picked up the car, it was running a little rough.  I
though the problem may be water in the electrical system and wasn't terribly
concerned.  However, once the oil temp had warmed up I tried to accelerate
briskly.  The car hesitated and back fired.  Immediately, I returned to the
shop. We diagnosed the problem as worn ignition wires and moisture in the
electrical system.

Since then I have replaced the ignition wires, the distributor cap and
rotor.  The car now runs great but there is a problem with the Tach.  It is
erratic, especially during hard acceleration.  The tach also appears to be
inaccurate at high RPM's.  The rev limiter kicks in when the tach is
displaying 6300 RPM's.  At idle the tach displays approx. 900 RPM's.

Below I have listed all the work that has been done in the past two days.

Replaced Control Arms
Replaced Driveshaft Coupling
Alignment
Valve Adjustment
Replaced Fuel Filter
Reset Service Lights
Replaced Ignition Wires
Replaced Distributor Cap
Replaced Rotor

The car ran great before going into the shop and it didn't have any
electrical problems.  Any help would be appreciated.

Tarun Kundhi
NCC
91 M3 (with crazy tach)

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