Running a diesel out / dual tanks

I know you were asking about the dynamics of the engine running out of fuel, but another problem, is running your in tank fuel pumps with too little/no fuel, it is not good for them.

Matt,

I wouldn't do it just as a matter of principle, however another good reason to NOT do that is because in the 7.3 the injectors use the fuel as a lubricant, and in case you haven't priced them, they're VERY expensive to replace. Secondly you run the risk of picking up "stuff" from the bottom of the tank, this could lead to all kinds of problems. I would highly reccommend you go to "thedieselstop.com" and just read through some of the information provided there. Ask questions, those folks are very knowledgeable. I think you'll like the site, I always learn something there.

Matt, I have two diesel Ford pickups, a Peterbuilt w/a Cat diesel, and my other vehicles are Prevost and MCI motorcoaches with Series 60 Detroiters in them. I have learned that it is best to run the tank down to 1/4 then fuel or in your case switch tanks. Given a diesel's abhorence for dirt or any sort of crud in the fuel, air, or oil, this is just a further safeguard for your motor. I don't believe that the 7.3 has a self-priming system on it. I know my 94 7.3L IDI does not, so if you run out of fuel a lot of cranking will be required to get the air out of the system. Of course, you can crack an injector to help bleed the air but still about three or four batteries will be required to restart it, unless you are very, very lucky. Just my observations. DaveD

It was my experience on mine, that if you're going 65+ mph when it goes down, you'll be fine. Just flip the switch, floor the pedal and wait. BUT if you're going to be puttering around with a low tank, then you'd better go ahead and switch it and wait 'till you're on the highway to run it out. At best, they're a real pain to start when they've been run out. At worst, you'll be bleeding the filter housing and cranking the battery dead.

The bit about running low on fuel being hard on pumps is a wives tale. There's no scientific evidence that it makes a difference.

the fuel is drawn off the bottom of the tank all the time. I never did understand this line of thinking.

Ya Steve, you are probably right. It a good bet all these other bozos have just been sucked in by an old wives tale... OK Then...

TEC TIP #1620 Federal-Mogul Document #1620, Technical Education Center Keeping Your New Fuel Pump and Fuel System Healthy Don't make a habit of driving with a nearly empty gas tank. Running out of gas is not only inconvenient, it can burn up your fuel pump since the pump relies on the gas flowing through it to cool it.

Allowing a pump to run with little or no fuel will cause the pump to overheat, leading to build-up and formation of gum within the pump housing and higher than normal amperage draw, resulting in a meltdown of the brush housing. Most modern vehicles place the pump in the tank where it can be kept cool with a constant bath of fuel, but this location isn't so ideal when it comes time to replace that troublesome component.

One thing that I did learn from dealer was that the only time the parts guy saw pumps dead this early was on short haul delivery trucks and taxis that were driven with mostly empty tanks of gas. (Being submerged is a coolant.) Turns out my van had been previously a hotel shuttle. So the when gas hits $4 a gallon and most people drive around with 1/4 tank and put in $12 every

3 days - it's gonna be a good time to be in the fuel pump business.

The pump needs a steady supply of fuel around it to maintain a reasonable operating temperature, and running the tank too low deprives it of this. It also makes the pump work somewhat harder, which means that running most vehicles down below the 1/4-tank mark (or thereabouts) is a good way to shorten the life of the pump.

Electric Fuel pump Placing the pump in the tank puts the component least likely to handle gasoline vapor well (the pump itself) farthest from the engine, submersed in cool liquid. The pumps are designed to run submerged in gasoline.

I agree the fuel cools the pump. BUT, if you run out, then the pump stops running. Then you switch tanks and the other pump runs. The most the pump could run with no gas is the amount of time it takes the oil pressure to drop off to nothing. I manage a fleet of 34 trucks, 18 of them fords and have not seen an excessive amount of fuel pump replacements. And we always run them till they drop before switching.