Peugeot 306 1.4 petrol tachometer malfunction

I own a 1996 Peugeot 306 XR 1.4l petrol.

A new problem has occured recently - not sure what caused this as I
haven't performed any work on the car - only driven it a bit. The
tachometer (RPM meter, rev counter) is stuck at ~2900 RPM. It also
seems to respond in an odd manner: when I drive - and when the real RPM
passes 2900 RPM - it seems that the tachometer moves to around 3000RPM.
It goes back down to 2900 RPM when I'm idling or not performing hard
work with the engine (less than 2900 RPM). When I power down the car
completely, the tachometer goes back down to 0 RPM - so this isn't a
mechanical failure.

Anyone has any ideas what the problem is (I assume a bad voltage
regulator or something of the type)?

 

advance512 wrote in message

If this tacho works the same way as mine (pug 405 1995 1.8 petrol) a pulse
signal comes from the ECU and chip inside the tacho measures the frequency
using a quartz crystal timebase and the output of the chip converts back to
an analogue signal to drive the tacho needle which is a old fashioned moving
coil meter. A really cack handed way of doing it as the ECU already
understands frequency/time and could drive a tacho direct.
You might get lucky and find a source for a new chip but a tacho swap from a
scrapper might be the best route. I expect you only need to get one from any
4 cyl petrol 306.
or
It would be an easy job for an electronics hobbyist to knock up a circuit to
drive your existing tacho. There is no need for a quartz timebase with
0.001% accuracy when the meter movement is possibly 2-5% accurate.

Bob