I've been using the dual tanks of my '96 as a sort of 'tanker' for the MC's. I remove the valve core on the pressure test schrader and attach a long piece of hose. I made a FP relay jumper w/toggle switch which I put in place of the relay to turn the pump on and off. My Q is: Anyone see any possibility of damaging the fuel pump doing this that I'm overlooking?

In case you're wondering why I'm doing this it's because our regional grocery store chain gives fuel 'perks' with purchases. The rules are once you build-up a discount and redeem the perks they must be used in one vehicle up to 30 gallons max. So you want to get the full benefit by filling a vehicle that has at least that capacity. I pretty much ride the 60 mpg bike in fair weather;-)

 

If you run the tank completely dry, you'll damage the pump & motor inside the tank. Click the black Bronco in my signature & look in the EFI Fuel Pump album. You might also find the Low Fuel Light album interesting.

 

Thanks Steve, yes I understand the importance of not losing suction on the pump. I believe they rely on the gasoline for bearing lubrication. I think what motivated me to post the question was that while I'm running the pumps with the electrical jumper they'll begin making some noise and change pitch even with full tanks. Possibly this is normal and something one wouldn't normally hear with the engine running (or the pumps might be going bad?). I suppose if I'm going to make a habit of taking gas out of this truck regularly I should remove the anti-siphoning tube on one of the filler necks so I can just siphon it out easier.

The amount of information on your site is mind boggling!

 

It has nothing to do with losing suction - the pump will reprime easily. The problem is motor cooling, & wear on the pump.

There's no anti-siphoning device in the filler neck. See views Y & Z.



Yes, the engine normally hides the pump noise.