Fuel light on. Gauge indicates otherwise.

[james944]

Hi all,

All is going merrily. Except for one thing.

I'm driving down the road and my fuel light comes on. No problem right? Yes and no. The fuel light is on but the fuel gauge is reading half full. Strange, as this early Porsche 944s (square dash) fuel sender float touches the bottom of the sender the low fuel warning light comes on but the gauge needle doesn't point to reserve which you'd expect it to do.

I've just tested a new (reclaimed) sender unit without installing it. I know, savvy eh. Same thing, the light comes on when I positioned the float at the bottom of the sender but the needle still points to half full. When I turned the sender over to allow the float to hit what would be the top of the sender the needle moved to full and the light goes out. Sadly when returning the sender back the other way the fuel light comes on but the needle again points to half full.

Is the problem then in the gauge itself? Could it be a frayed wire somewhere?

Anyone else suffered with this problem and how did you solve it.

Thanks
James

 

[tref]

Remember the tank isn't the same section all the way down - there is certainly a "well" at the bottom, so half-way down the sender may well be nearly empty... I must admit with any car I try and "learn" the gauge... My current S2 I know I can do about 400 miles on, and at least 25 miles after the light comes on, but I have covered forty + miles with the light on. Admittedly the needle will be on the bottom of the gauge on that. Early dash cars I have normally seen the light on with about 1/4 tank indicated as I recall. Even the S2 fluctuates by about 1/8 tank according to how it feels for any given actual volume...

 

[tref]

Oh, and what do all the other gauges do? One of my Turbos all of the gauges read higher than the other cars - I have guessed this to be something to do with the voltage regulator on the dash...