18 gallon fuel tank, correct?

[John Larkin]

The car sits endlessly. I let it get really low. Went and bought 5 gallons today and poured it in. It only shows 1/8 tank. I probed the sending unit which showed 12 ohms. That sounds like 1/8 tank to me. But the tank doesn't hold 40 gallons (I can do math). The last time I had the sending unit out, it swept perfectly from 0 - 90 with no issues. I wonder if things get exponential at some point? I am adding another 5 gallons in the morning and will retest. It is a stainless Racetronix sending unit and hanger.

 

['87 Turbo "T"]

Yep. 18ish.

 

[John Larkin]

Ah, the joys of antique cars. I got 5 more gallons this morning and read the ohm meter. Still stuck on 12 ohms, oh no. After 30 seconds of thinking about it, I bounced the rear of the car for about 30 seconds. The ohms began to climb and stopped at 52. I started the car and voila, just over 1/2 tank showing on the gauge. That should be correct with 10 gallon + what little was in there before. Mystery solved. Now to solve the mystery fuel smell.