My 1986 chevy pickup has dual fuel tanks and the problem is the gas gauge jumps up and down regardless of how much fuel is in the tanks whether left side tank or right side tank.

Harvey N Tawatao

• 3854 Answers
• Posted on Apr 06, 2009

SOURCE: 99 chevy silverado fuel gage malfunctions

What cases this is a bad signal from your sening unit in the gas tank. Before you go out tearing that apart check the wire harness from the tank to the frame. The wire's may have a break in it and Good luck

SOURCE: Fuel leaks from rear tank to front.

The leaking from one tank to another was covered by a recall from Ford. Not sure if they still foot the bill for installation of the required check valves. These are still available from the dealership. The rear one is the hardest to install. The check valve can be installed without pulling the rear tank. As for your front sender I would clean all of the connections to the sender and make sure it has a decent ground. If it still only reads at the 1/4 tank level you will have to replace the sender to rectify the problem.

SOURCE: 2002 Chevy Suburban: Fuel gauge reads empty, tank is half full

Youre gauge is controlled by a plunger in the fuel tank which is attached to the sensor and the fuel gauge. it sounds like when the plunger goes down half way its either getting stuck down lower then it should. Needs replacing. Any mechanic can do this install for you.

SOURCE: 1982 chevy truck with dual gas tanks with guage or tank problems

all you need to do is listen to hear the tank switching valve is working. It will make a soft noise under the rear cab section with the key on with the engine off. zif you do hear it sounding the switch your tank unit for that one tank you try to switch to is a fault. Sorry no illustrated diagrams are on hand, just knowledge

SOURCE: 2002 Chevy Silverado 3500 Fuel gauge reads 1/2

If this was not a problem before the pump replacement then the sender in the tank may of faied or is contaminated with sulfer which is corrosive to the silver electrical contacts.

Do a search on sulfur corrosion and fuel sender units. Gm has big problem with this. Its possable the stress from removing the old and installing the new pump created an issue with contacts. If this is the case you will now need a sender unit.