Oil pressure gauge FSD

[MarkP]

Hello fellow Carpokers,

Our 944 oil pressure gauge always reads full scale deflection. I believe that if the two terminals are reversed this is the result, however I have reversed the connections to no avail.

I have checked the wiring in the engine bay and all seems good, so the fault would appear to lie behind the instrument cluster. Having never tackled this kind of a problem before, what should I be looking for exactly? Has anyone had the same issue perchance?

As usual, any guidance is appreciated!

[walfreyydo]

The early 944s and late 944s had different gauge setups so knowing the year of your car would be helpful.

Assuming you have a late 944 (oval dash) the gauge cluster backside has some black oval "football" shaped contacts for each of the four secondary gauges (oil pressure, fuel level, coolant temp, voltage). On that contact is a small hex nut. Make sure the nut is fairly tight and free of corrosion on the contact point that the nut makes with the blue flexible circuit board. Typically this is more of an issue with gauges that tend to "bounce/twitch" but still worth doing if you are in there.

Secondly, you should also test (or replace) your oil pressure sender, as these can also show pegged readings when the sender is bad.
https://www.clarks-garage.com/shop-manual/lube-03.htm

[MarkP]

Thanks for the swift reply walfreyydo - ours is an early 944 - 1985, made just before the transition. I will pull the dash apart around the gauge cluster and see what I can see.

[944er]

Most likely the sender unit. One wire goes to the gauge, the other to the light.

[MarkP]

Thanks 944er - I have changed the sender for a new unit, so I will investigate the wiring now.