ID this fuel level sending unit, please

[dameeks]

I'm having problems with my fuel level gauge. I have Autometer Phantom gauges in an FFR MKI. Gas tank is from a 91 Mustang. The gas gauge was reading backward, so I measured the resistance of the sending unit. It shows that it is about 35 ohms when full and just under 200 ohms when empty. So, I swapped gauges with one that reads 33 ohms when full and 240 when empty (I know, it's not an exact match, but it was the closest thing I could find). Now the gauge reads in the correct direction, but only reads 3/4 full when the tank is full. I haven't had the chance to see what it reads as the tank is emptied, yet. So, I'm wondering if there could be something wrong with the sending unit itself. I didn't build the car myself, so I'm not exactly sure what sending unit is in it. I pulled the unit a few days ago and snapped a couple of pictures.

Can anyone tell me if this is the stock Mustang sending unit? Or, if not, what this unit is and how I get my gauge to read correctly?





Thanks,
Darren

[Double Venom]

One of two problems, you're still not matching the correct sending unit to the Autometer gauge, OR since the sending unit you are holding appears to be adjustable for different tank depths, it's simply not adjusted to match your tank.

Hook up your sending unit to the gauge and run the float all the way down and back up manually. If it then reads correctly, adjust the float depth to match your tank. If it still doesn't read correctly, simply call Autometer and order the correct sending unit.

DV...hope this helps

[dameeks]

I tested the sending unit while it was out. It reads 200 - 35 ohms, empty to full. I knew the autometer gauge wouldn't be exact (240 - 33), but what I did expect was that when full, my sender would read 35 and the gauge would therefore appear full. I just checked and the resistance at the sending unit is about 41 ohms, and the tank is about a gallon shy of being full, yet the gauge reads a little over 3/4 full. I'd really like to avoid pulling the sending unit out again, as it's in about the most difficult place in the car to be able to get to, without dropping the tank.

What I'm really wondering is if the sending unit is the stock mustang one (based on a few pics I've found I don't think so). And, if it's not, what the heck is it? I can play around all day trying to match up a gauge to the resistance, but I'm hoping I can tell Autometer that I have an xxxx sending unit, and then they can tell me which gauge to get.

Thanks,
Darren