Fuel gauge (dual tanks)

[Busaman]

So my righthand (auxillary) sending unit came in finally, installed on tank and began hooking up to the truck. Had another broken wire (red/whitestripe). fixed that and it seemed to take care of the problem. I began to actuate the switch from left to right tank and my left side tank (drivers side) stopped working!!!!!!!!!!!!! Took a break thought about it for a while and thought screw this, I"ll install the right side tank and then drop left side back down and start looking for bad wires on that side. Keep in mind I just replaced (left side)sending unit last week.I took a meter to the selector valve. Had good connection on both red wires but couldn't even get continuity on the 2 green wires . Went inside, ate dinner came back out to the garage switched tanks back and forth about 5x and both side worked just fine. Thoughts???

 

[Busaman]

By looking at the schematic, I either have a faulty switch or selector valve? I also replaced the selector switch out last week.

 

[Boone83K10]

since I went through this about 6 months ago, your selector valve is failing. Mine was an electrical fail. It was switching mechanically, but would give false readings. It would say my driver tank was always 3/4 full and passenger was always 1/4 full.

Pretty easy to change out minus the stupid fuel clamps. Mine were turned towards the frame rail (GENIUS!!)

 

[Busaman]

And you've never had a problem since?

 

[Boone83K10]

nope...

I replaced the entire passenger side. Fuel lines, tank, sending unit, selector valve, selector switch and I completely cleaned out all the gunk in the filler/vent hoses, oh and don't forget new gas cap! lol

I had to... here's why

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[Busaman]

holy crap man!!! that's looks nasty. Thanks for the info. I've done everything but the selector valve. I"ll prob sit on it for a while.

 

[Boone83K10]

I would go ahead and replace it because they really are pretty cheap. that way you won't be stranded in case it fails while you're driving it

 

[Busaman]

Yeah it looks like I"m going to have to. Which one did you go with out of curiousity? (BW or AC Delco)? I was under the truck checking it out last night. Did you remove or loosen the crossmember at all? It was tough for me to get my hands up in there on some of the lines.

 

[StickDeath]

So i have the same set up on my 73 and they guy who owned the truck before me said the passenger side tank was giving him problems. So he just cut all the wire back the fuel selector value. Could this be the reason why my fuel gauge isnt working ?

 

[Busaman]

After diving head 1st into this issue, I don't think it should matter if the wires are cut back on the one side. Once that solenoid is switched to the other side(working side), it should only be measuring resistance on that side.

 

[Boone83K10]

Yeah it looks like I"m going to have to. Which one did you go with out of curiousity? (BW or AC Delco)? I was under the truck checking it out last night. Did you remove or loosen the crossmember at all? It was tough for me to get my hands up in there on some of the lines.

I did not remove the crossmember. Did you take off the stone guard? Mine is missing so I could easily see it. It wasn't fun with the fuel lines trust me. I unbolted it and the lines move just a little so you can work with it.

I bought this one..

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http://www.autozone.com/autozone/pa...tor-Valve/_/N-8ve9x?itemIdentifier=18894_0_0_

 

[Boone83K10]

So i have the same set up on my 73 and they guy who owned the truck before me said the passenger side tank was giving him problems. So he just cut all the wire back the fuel selector value. Could this be the reason why my fuel gauge isnt working ?

what is the gauge doing? is it a "3 o clock"? that would be a bad ground. If it's staying the same then it could be a sender or selector valve or the gauge.

 

[Busaman]

yeah I removed the rock gaurd. I assumed it was a heat shield. My selector valve was so flakey, I just had to go buy a new one to prove it out. I checked continuity at the sending units, sometimes I had it(continuity) and sometimes I didn't. The ports on the new valve is larger than my current fuel line. I jumped up a size in fuel line, which wasn't a big deal I had intentions of replacing all the fuel line anyway.

 

[StickDeath]

what is the gauge doing? is it a "3 o clock"? that would be a bad ground. If it's staying the same then it could be a sender or selector valve or the gauge.

its almost in the 6 O clock position. Doesn't do anything i was hoping maybe a cut wire but nope.

 

[Boone83K10]

6 o clock??????????????????????????


that sounds like a broken needle. Just flopping away on the bottom.