I’ve been trying to get to the bottom of this but haven’t had much luck. I recently purchased an instrument panel with rev counter on impulse as I saw it didn’t have a glow plug light so I thought “great, it must be for petrol”.
After some research it seems the red area on a diesel rev counter starts just under 5000rpm and for petrol it starts just over 5000rpm, but I’m not sure if this is true in all cases. I realise I may have been jumping to conclusions basing it on this fact alone.
Can anyone answer any of the following:
1. Is it possible to ID whether this is for petrol or diesel from the pictures below?
2. Is there any harm in just plugging this dash in and seeing what happens? Alternatively I could just test the rev counter on it own. I’m aware there are three connections to the rev counter (positive, signal from coil, and earth) does anyone know which is which?
The blue ribbon looks like it’s had some wires soldered on to repair it. If the rev counter is petrol I’ll do away with the blue ribbon and get a wire kit.




Cheers,
Scott