Need help with dual saddle tank issue

[dbreid]

I have a 1984 K30 with the dual saddle tanks, and I love it. I know, people will tell me to swap to a 40 gallon from a suburban, etc... But I kinda like the Saddle tanks.

Now, for the first year or so of owning the truck, everything worked great. They swapped back and forth, and everything was cool. Then, on my drive to the Rubicon (happened on the highway on the way there!) I lost the ability to swap tanks. Kinda sucked for the trip, but I worked around it with a siphon.

When I got home, I decided I wanted a well functioning system, so I went out and bought a new Switch (in the dash) and a new "junction" thing under the truck (the one that has the wiring harness and the million hoses going into it. So I replaced them both, and I still can't get it to switch....

Any advice?

The gas guage works (it comes up when you turn on the truck, and follows the tank), and everything works on the truck itself, but I just can't get it to switch. What else can I try?

I read the whole manual on this topic (I have the factory one), and it was less than illuminating.

Thanks in advance for any tips.

-Dan

 

[reddog64]

have you tried blowing all the hoses out, off the tanks of course???

 

[Jason4x4]

how do you know it isn't switching?

 

[dbreid]

answer

how do you know it isn't switching?

I guess I don't, really. Before I had the trouble, when I threw the switch, the gas gauge would swing to show the other tank's "fullness". I purposefully have one full tank and one half empty tank, so I should be able to tell when they switch.

I suppose it is possible that the tank is switching, but the needle isn't reading properly (which would be an electrical issue, I guess), but I am not sure how to debug that.

Any advice?

-Dan

 

[bigbadchev84]

hope this helps

 

[dyeager535]

These things can be a pain eh?

How easy is it to get to the solenoid? I'd probably try siphoning from somewhere between the fuel pump and solenoid, with the tank you know works disconnected. That'd tell you if its switching at least.

Other option is to drive around on the tank you THINK is the half full one, with a 5 gallon gas can in the back of the truck, until it starts to die, then hit the switch and see if it runs fine again.

The gas gauge portion of the dual tanks seems to be problematic, but probably only because dual tanks have twice as many components to fail as the single tank setups.