temp gauge playing up

henry944 · Aug 31, 2009

Hi everyone, this is my first post so be friendly!

I have just bought my first 944 1985 lux. However the temp gauge goes up and down as quick as the the oil pressure. its very odd! The engine was changed by porsche to a 2.7 1987 engine with lower miles. Could they have forgot to change the temp gauge to the 2.7? Im guessing it runs hotter than the 2.5.

The temp just goes up and down so quickly even though the engine isnt actually overheating. Any suggestions would be greatly appreciated. thanks

Mike_Pollock · Aug 31, 2009

Hi

Sory no idea - wish I could get mine to read even get on the scale!

Oh and good choice and welcome to the mad house!

Mike

scam75 · Aug 31, 2009

I had a problem with my gauge shooting sky high intermittently. Sometimes flicking the dash with my finger made it behave again! This pointed to a faulty gauge which has been replaced now. Funnily enough the new gauge sometimes sticks at absolute zero on start up. Nothing a quick flick of the dash doesn't correct!

Does it ever function properly or is it always erratic?

DavidL · Aug 31, 2009

It'll be electrical - possibly a bad earth, iffy wiring or a dodgy gauge.
Is 85 an oval dash or not?

henry944 · Sep 1, 2009

Thanks for the responses! It always plays up, never works properly. A flick of the gauge sadly doesn't do the trick.

It's an oval dash, and a bad earthing is the most likely as the battery dies after it's ben sat for over a week. Thanks for the info!

DavidL · Sep 1, 2009

As its an oval dash its easy to take the dash clocks out and change the temp/fuel one over.

At least you will be able to see if it makes any difference. Somewhere on Rennlist there is a picture of all the earth points - I would spend an hour finding as many as possible and clean them up.

If you are handy with a multi meter you can look for current draw.
These aren't exact instructions but it goes something like take all the fuses out, connect it to one of the battery terminals and then to the battery and then look for big deviations when you put each fuse back in.

Hopefully someone will be along to elaborate on this and stop you blowing the car up!

I'm currently running a new temp/fuel gauge in an attempt to stop the occasional flick to boiling as I go along. I know the car is fine - it will sit for a good hour and cycle through fan on and off with no issues - but that doesnt help the heart rate when a casual glance at the gauges reveals a very odd reading.

Typically whilst the temp seems ok the fuel gauge has a bad earth or similar as it reads full all the time. So it seems I have one gauge where one works and one where the other does. Great!