Gday all,
    I have 2 issues. 1 -  The fuel gauge dosent work, no matter how much fuel is in the tank the gauge reads about 3/4 full.
                does anyone know what values I should be getting back from the fuel tank sender ? What Ohms should you get at low and high fuel tank levels?
                            2 - The tacho seems a bit erratic especially when revving out quickly. Sometimes it will sit on an rpm for a few seconds as the engine continues to rev, and the jump up to the new revs after a delay and continue this pattern.
   Im wondering if its an earthing problem at the dash cluster given 2 gauges have issues at the same time.
   Any thoughts welcomed

sounds like mine..
 
interested to hear replies
 
 

I have my old sender that i could measure if i can get it to work well enough to test but I dont have time today, might have to be next week. If i dont do it soon or nobody else replies remind me via a pm
 
Have you had the sender out? could be stuck at that point? I bought a resistance wheel from an electrical store and connected it in series with the wires at the tank to see if the guage was working and mine worked, as in changed when i altered the resistance wheel so i knew it was the sender. I was quoted $95 to fix the sender so i dodgied up another i found.
 
Havent got a clue about the tacho though sorry
 
Ryan

No haven't got the sender out, Im just at the start so hoping to save some time using other peoples experiences. Ive never considered using the potentiometer to check the gauge, that's a pretty good idea!

Here is the resistance specs for the fuel gauge.
Empty = 73 ohm
Half     = 23 ohm
Full      = 10 ohm
 
Cheers
 

I recently had a tacho doing weird and wonderful things.  At the next event I had an electrical short that stopped the car (part of a loom had rubbed through).  I believe the tacho issue was related to this shorting out within the ignition system.  Short story, yours sounds like a short or earth fault but really I am only guessing.