Rear tank not working!

Hey guys, I’ve been trying to get my rear tank working again. As of right now I can only run fuel off of the front tank. When I flip the selector switch it stops pulling gas from the front tank but doesn’t start pulling it from the rear. I’m not sure what the issue might be here. Both sending units have been replaced, the selector valve has been replaced, and the selector switch has been replaced as well.

Thanks in advance for any help.

If you have electric fuel pumps in the tank, can you hear it running?

Hate to be the one to say it..

Replacing a part does not mean the new part works. Can you test the rear sender?

I think you need to measure the voltage going to the selector valve.  also double check all fuses. for some reason I think the selector switch gets power from a shared fuse on some models, but I cannot say for sure. you might study the wiring in documents page.

You’re right, and I’m thinking about checking it again, but just a little while ago my selector switch went out and it defaulted to the rear tank without me knowing and ran out of gas. So as far as I know the sending unit can work.

Replaced all the fuses the other day, I’m going to buy a test light soon and check all the connections I can soon.

This image from the EVTM shows fuse 15 should be hot in start and run.




The fuel system defaults to the rear tank if the selector valve solenoid is not energized by the brown/white wire.
Sender switching is done by the switch in your dash.





Hope this is helpful.

Is this a "3" port selector valve type, located on the frame? With one electrical wire going to it.

If so the rear tank is the default tank and the front tank is the secondary.

With no power at the selector valve it should default to the rear tank. If it isn't then you may have the hoses reversed at the valve.

Figure 2 on pg. 100 (above) seems to show a straight fitting and a 90° fitting.
I'm not sure you could get them reversed?  But you have a good point!

On my 1981 there is no 90 degree fitting and the hoses are just hooked up to the valve with hose clamps. So a reversal of the hoses is extremely easy. The 1983 should be identical if not very similar.

Things did change with the in-tank fuel pump, but the 1983 with 302 should still be mechanical fuel pump only. (From the Factory anyway. )

Good to know!

I'm afraid I don't have anything to go by except the examples in the EVTM's here on the site (unfortunately there is no '82-'83-'84) so your experience is invaluable, Ralph.  

Even if the hoses are reversed it should still work in theory though right. Just pulling from the wrong tank? Right now it pulls gas from the front when it’s selected but pulls nothing when it’s set to rear

Yes, but the senders are controlled by the switch so you would be reading the opposite tank.

Perhaps you should check the line between rear tank and valve. If there's a crack or hole there the pump couldn't pull fuel.

Michael Cesaro wrote

Even if the hoses are reversed it should still work in theory though right. Just pulling from the wrong tank? Right now it pulls gas from the front when it’s selected but pulls nothing when it’s set to rear

Yes, it should work backwards, but as Ardwrkntrk states, you wouldn't see the fuel drop on the fuel gauges, when on the correct tank by the switch.

If the selector valve is defective, and hooked up backwards, it will default to the front tank. It will not pull anything from the rear tank no matter how the selector switch is switched.

If Fuel will not pull from either tank, (from the Front and Rear Tank) when the selector valve is in the rear "position":
   1: Temporarily hook the selector valve up backwards. If symptoms switch to the opposite tank, replace the selector valve.
   2: If the fuel still will not pull from the rear tank, then follow Ardwrkntrk's advice and see if there is a hole in the fuel line between the tank and the selector valve, including the fuel sender. I've seen the sump of the fuel senders spring a leak, and would only pull fuel above half a tank before. I've also seen the fuel lines plugged as well. The filter sock at the end of the sender for instance.

One of these suggestions should get you working again.