• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

fuel sending unit

Share this page

6

69tr

Jedi Trainee
Offline
Does anyone know how many ohms the fuel sending unit should read in both up and down positions? (69 TR6)

My fuel gauge does not work and the easiest thing to check right now is the sending unit.

Thanks, Pete
 
I do not have first hand information specific to the TR6, but most Smiths sending units (after the introduction of the voltage stabilizer in the mid-1960s) operate from 240 Ohms = Empty, to 30 Ohms = Full. Those values are nominal, your exact readings will vary a bit from that range.
 
Perhaps this will help.
My '74 TR6 has a properly working fuel guage. When trying to get the TR3 one to function, I made the following measurements on the TR6:
0 ohms@Full, 52 ohms@1/2, 128 ohms@1/4.

My (early) TR3 is completly different, and I think the TR4 is also different.
 
Those values sound very plausible if Smiths didn't standardize on one resistance range.

Any of the vehicles without the voltage stabilizer (definitely the TR3) will be different as you say. The systems without the stabilizer will go from near 0 Ohms at empty to somewhere in the vicinity of 90 Ohms at full. (Increasing resistance as the tank is filled as opposed to the stabilized system where the resistance decreases as the tank is filled).
 
Back
Top