Help!1986 silverado dual fuel tank system wont work.

[355bullet]

I have a 1986 silverado with a dual fuel tank system. I just replaced the switch valve (acdelo) and the selector switch. I will not work, the fuel gauge passes the full mark for the passenger side tank. Any Ideas?

[pontgta]

Probably bad fuel pump or bad hose exiting the fuel pump

[355bullet]

brand new fuel pump, the truck runs

[Gmc.guy]

Is your truck Tbi? I would clean up the ground on the sending unit and the wire plug. I know that if you take the gauge sender wire off it will go past full and if you ground it out it will fall below empty. Usually a clean up if the wires will get it working again. Your saying the truck runs ? So it is switching tanks, just the guage doesn't work once it switches ? I'm not 100% I think it's a light tan wire for the fuel level and the others are for the pumps. Been awhile since I worked on a Tbi truck

[pontgta]

[QUOTE=355bullet;7501679]brand new fuel pump, the truck runs[/QUOTE

Runs on both tanks? just the gauge not switching? If so, you have a bad sending unit, fault in the sending wire from that side. I would start by grounding the wire from the tanks to see what happens.


Your 86 should be carb, so forget what I said about the bad pump. I thought you had in tank pumps

[355bullet]

I replaced the switch valve and switch. It wont switch over to the other tank. Right now its getting fuel from the passenger side tank.
It originally a carburetor truck
thanks in advance

[school boy]

I had nothing but trouble out of selector valves. I went through 2 new valves in 500 miles. I just ended up wiring up and installing new lines on one tank. The valves would lock up and wouldnt switch over. The last one wouldn't let fuel return to the tank.

[jocko]

this is likely the ground wire or sender for the passenger tank. Going past full is usually a ground wire issue.

[355bullet]

Thanks! I'll trace the wires