Rev Counter Not working

[samsaudi]

The rev counter on my 1990 C3 has developed an intermittent fault , sometimes it works ok other times the needle just sits at the bottom of the gauge not moving at all . Any ideas ?

Also -

Does anyone know where in the engine area the revs are measured , perhaps there is a corroded plug/connection or sensor . Any ideas ?

[dansp1]

I had the same problem, it was the pcb on the back of the clocks, found it by stripping the dash and flexing the pcb with the clocks all plugged in
http://www.sjmautotechnik.com/troubl...nt.html#speedo
some stuff on here

[msh]

Originally Posted by samsaudi

Also -

Does anyone know where in the engine area the revs are measured , perhaps there is a corroded plug/connection or sensor . Any ideas ?

Unlikely. RPM signal comes from transistor amplifier if it's K-jet or carb, or ECU if it's KE-jet or motronic - and one connector from engine wiring harness connects straight to instrument cluster. Ok, I dunno about RHD, in LHD form C3 has ignition control unit located in fucking place - below bonnet opening lever - if rubber seal through which bonnet opening cable passes, leaks, ignition control unit receives water

[pimpdriver]

Originally Posted by msh

Unlikely. RPM signal comes from transistor amplifier if it's K-jet or carb, or ECU if it's KE-jet or motronic - and one connector from engine wiring harness connects straight to instrument cluster. Ok, I dunno about RHD, in LHD form C3 has ignition control unit located in fucking place - below bonnet opening lever - if rubber seal through which bonnet opening cable passes, leaks, ignition control unit receives water

Where is the transistor amplifier on my B2 80 with a carb?

My rev counter hardly ever works.

[msh]

I have no idea about RHD B2, on LHD B3 it's bolted to left A pillar where it meets sill, next to drivers left foot.

Anyway, it seems from schematics that B2 more likely takes rev signal from ignition coil - although it seems that both approaches were used.