5 replies to this topic

[jeffster06]

I recently did a center smiths speedo conversion from my 3 clock mini (91 Cooper). Initially everything appeared to be working ok, except now the fuel gauge always reads E. Things I have done/tried so far...

 

Topped off tank, when I first did the swap the gauge read full which I believed was correct because I had recently filled up before starting the swap. When it showed E I wasn't feeling confident so now I know the tank is full. 

 

Measured sender resistance at the tank, I measure about 15 ohms

 

Measured the sender feed at the fuel gauge, I measure about 18 ohms

 

Checked the voltage off the stabilizer and have 10 volts being fed to the gauge. 

 

Tried grounding the green/black wire from the sender, gauge doesn't move at all. 

 

Not sure what else I can check, the gauge is brand new, is it possible it is defective? It appeared to be working initially then I noticed it wasn't working anymore, I had only driven 20 miles or so when I noticed it was on E, should add I didn't notice it while driving just while warming up to take it out on a different day. 

 

I want to test the gauge itself, am I correct in assuming if I put a 50 ohm resister on one leg of the gauge to ground it should show something on the gauge?

[Swift_General]

Either short the wire in the boot in the sender to earth or (better way as it eliminates the sender wire to boot) shirt the sender side of the gauge to earth. Gauge should go full. Is the temp gauge working?

[jeffster06]

Either short the wire in the boot in the sender to earth or (better way as it eliminates the sender wire to boot) shirt the sender side of the gauge to earth. Gauge should go full. Is the temp gauge working?

Temp gauge is mechanical so its not affected. I tried shorting the sender side of the gauge to earth and it doesn't move at all. I measured the resistance across the gauge as well and it shows open. 

[Swift_General]

If the sender side of the gauge is earthed and the other side at 10v then sounds like gauge is duff unfortunately. I'd just do a final check by wiring it up as such and measuring the voltage of one side of the gauge with respect to the other to make sure the reading is around 10v ( or -10v).

[jeffster06]

If the sender side of the gauge is earthed and the other side at 10v then sounds like gauge is duff unfortunately. I'd just do a final check by wiring it up as such and measuring the voltage of one side of the gauge with respect to the other to make sure the reading is around 10v ( or -10v).

I will give that a try, Hoping the place I purchased the speedo from sends me a replacement fuel gauge, seems this one had a defect. 

[jeffster06]

Finally got around to testing the voltage across the fuel gauge. Read 10 volts across it with the ignition on. Rechecked the resistance on the sender wire at the fuel gauge cause I drove a little. It was from my last reading of 18 ohms to 32 ohms so I'd say the sender is working correctly.