Can you rephrase this. I`m not sure what your saying. Try unplugging the the front tank and see if the back tank works right like it did before.

 

There is no air commingle out of the fuel rail. The back tank is working fine.

 

I didn`t see any thing that said the bulb turned on momentarily in the thread or I missed it.

 

Check Hilda never comes on. Is it hard to get to replace?

 

I wounder if the wires on the pump it self are right. Ohm test them. Pump side is really low on resistance and the gauge sending unit is 8-73 ohms. 8-73 ohms is depending on how much gas is in the tank.

 

If that tank hasn't been used in a long time the tank selector switch may be corroded because it hasn't been flipped in a while. You can take it apart and clean the contacts, I had to do mine because I hadn't used the front tank in years.