Porsche Enthusiasts Club Forum

Hi Folks,
I own a 944s2 from 1990. I brought the car around 6 months ago. The car needed a
few minor fixes, small stuff really, changing fuses and fixing the drivers door so that
it would open from the outside not just from the inside!. Apart from that the car is
an absolute pleasure to drive and I use it daily around 60 miles to and from work.

I have a problem with the combined petrol/temp gauge. If I fill up the car full (80 litres)
the needle on the petrol gauge only ever goes up to the 3/4 full line, never up to the
top. After much driving, when the needle comes down to the bottom (R) reserve line,
the reserve light does not come on right away. I can drive a lot more miles before the
reserve light comes on. When the reserve light comes on I drive to the petrol station,
fill the car up full again, only to find that there was not around (8 litres) of petrol left
in the tank as it should be for reserve, but around 16 litres?. So there is always more
petrol remaining in the tank and what the petrol gauge reads.

I brought a new petrol tank "sender" unit and installed this hoping to fix the problem. It did
not. I've had a couple of suggestions from friends, could be dust in the gauge, on the
needle, or that it could be some kind of an electrical "short" problem. I am a bit wary of
going out and paying £150 for a new gauge only to find that it will also not fix the problem.
Please as anyone seen this problem before? I would really appreciate some good
suggestions and advise.
Thanks/Warren

Either bend the float arm on the sender to suit or some gauges can be adjusted to 'calibrate' them

Electrical shorts will 99% of the time cause the gauge to stay at full

Dust on the gauge never heard of that being a problem and doubt if it ever could be

Hi Dave,
Thanks for your reply. This problem existed before with the old "float" (petrol level
sending unit). I have installed a new one, so surely I do not have to "adapt" the
float arm on this new unit to cure the gauge fault? Do you think that buying a new
gauge will cure this annoying problem?.
p.s check out the website below for this new innovation in spark plugs. I have been
using these pulstar plugs now for 5 months. The car does have more torque and feels
more lively with these plugs. They are a little expensive but when you consider they
last around four years, they eventually pay for themselves.

http://www.pulstar.com

Thanks again Warren / 944 s2

Err, I wouldn't try & fix it because they all do that! I used tofind it quite frustrating with mine when it was my daily driver but got used to it. I can't believe the "precise" germans allowed it out like that!

Just bend the arm, we had to do it all the time on Fords

It won't alter the other end of the range though will it! The whole range seems compressed from 1/4 to 3/4!

With my old gauge I didn't have this problem. (The one you got Jim) Now I have! So If it bothers you that much you could try a different gauge. But get a second hand one! £15ish is the going rate for the full cluster including speedo & rev counter. The stock gauges are poor quality. I don't remember any adjustment on the gauge itself. Once your used to how many miles on a tank it's less important.

Hi

I had a similar problem on my 928, someone told me to try this and it worked ...lol....and I was amazed

Where the sender joins the loom are four spades...on a 928...

I was told to CLEAN all those 4 spades and they have to be bright and shiny not just look ok....

I did it and unbelievably my gauge at full moved from just over 3/4 to totally full, it actually worked, so worth a try......

I think now that minuscule bits of corrosion on the connections was altering the resistance sent to the gauge...

All the best Brett

Hi Warren,

My car does exactly the same thing as yours. The actual tank capacity is 88 litres. The drivers manual suggests that when the low fuel light comes on, you have about 8 litres of fuel left in the tank. I then drive another 30 miles or so then fill up. When I have totally brimmed the tank, the petrol pump indicates I have put in about 80 litres. I reckon that there is another 8 litres in the car still before I need to fill up. So in theory, I should be able to drive 60 miles from when the low fuel light comes on before hitting rock bottom. Anyway, I would only try this if I had fuel can in the boot!

The guage is only an indication of the contents in the tank. There is so much movement on the gauge too. If on an incline, you can appear to have more or less in the tank. I would n't worry about it too much.

Regards, Ben

my gauge varies dependant on which way you are turning or if you are accelerating or braking hard !!

My 1991 S2 does similar strange things when it is full to the brim it reads full then takes forever to move off the top stop, when it gets to empty, indicated by the reserve light going on and I fill it up I can only get 60L in so my reserve is around 28L. But I just live with it and fill up with the reserve light on at least I only have to put 60L in rather than 80L and I know if mine indicates empty I still have plenty of available fuel.

I did think the reserve on the S2 was more than 8L I thought from memory my handbook indicates 12L or 15L reserve whereas my 924S is stated as 8L might be wrong though.

Hi,
Found this useful article from Pelican parts in USA. Titled " Solving strange
944 gauge problems". Shall give this a go soon. I will get that blinking petrol
needle from 3/4 to full. Also my odometer is not working but am hoping that
will just be a problem with the switch in the dash, the back connector pins
or something and not the odometer plastic gear.

http://www.pelicanparts.com/techarticle ... oblems.htm

Also I found another site which sells the plastic gear to fix the odometer
and 944 stainless steel hatch lock pins (they don't rust,).

http://www.rennbay.com/928-mph-odometer-gear-p-53.html

http://www.rennbay.com/944-hatch-lock-p ... p-123.html

Rgds/Warren

Hi All,

Interesting articles. My only concern is why you would disconnect the negative wire from the battery. Being an Electrical/Electronic Engineer, I have always disconnected the positive side. The reason being that if you disconnect the negative side, it could short onto another source i.e. bodywork etc and in effect create another circuit/short circuit. In my opinion, you are always safer to disconnect the positive side.

Regards, Ben

You should always disconnect the earth wire first, less chance of causing a spark as you remove the cable.

If the alternator had been overcharging the spark could cause the battery to explode