Don’t run dry. Just don’t. Please don’t run so low on diesel fuel that it will literally run out of fuel while you’re driving. This doesn’t just happen suddenly and without warning. If you’ve paid any sort of attention to the multitudinous low fuel warnings that preceded running out, you knew what was coming and then sent it to the back of your mind. Despite ample warning, the diesel really will stop flowing at some point and it really will be game-over.

Running out of diesel fuel in your heavy-duty Cummins, Duramax, or Power Stroke diesel truck is more than just an inconvenience. Unlike gas engines that can often be restarted with a quick refill, diesel engines have unique fuel delivery systems that make running out of fuel a potentially more serious issue. So just don’t—but if you do, think before you crank.

First, How Will It Feel?

You’ll likely remember what’s wrong before you come to a full stop—which will happen in a matter of seconds. Your truck may begin to hesitate, lose power, or sputter under acceleration. At this point, if you can shut it off before it dies, that would be ideal. It will stall completely, usually with a hard jerk. That’s your diesel engine starving for fuel—specifically, air entering the fuel lines where diesel should be. The dashboard will light up with various warnings (maybe about reduced power and emissions); the check engine light will go on.

Note that diesel trucks don’t run out slowly and without fuss. It is sudden and violent. The whole process could happen in under 100 feet and in less than half a minute. There’s no question—you know exactly what’s happening.

For example, a light turns green and you accelerate. Halfway through the intersection, it feels like you get rear-ended hard enough that you nearly bonk the steering wheel. The truck sputters violently and it sounds awful. For the sake of safety, you get through the intersection before attempting to pull over. The truck dies immediately and you lose power steering and power brakes, leaving the tail-end partly in a lane. This was ideal, as you had a shoulder to pull onto. Luckily you weren’t on the freeway. To reiterate: not only is this bad for your truck, it’s a bad situation for your safety because you don’t have enough warning (once it’s literally running out).

Is Running Out Of Fuel Bad for My Engine?

The first real danger lies in introducing air into a high-pressure common rail fuel system. Diesel engines are sensitive to air. Air pockets can reduce fuel pump lubrication and create cavitation, potentially damaging the injectors or fuel pump—especially in newer emissions-equipped engines. Secondly, in addition to general strain on the fuel pump, sucking fuel from the bottom of the tank introduces grime and bottom-of-the-tank gunk.

What’s the Restart Procedure If I Run Out Of Fuel?

Each brand has a slightly different procedure, so it’s best to consult your owner’s manual before you try restarting. However, here are the general steps:

1. Refuel the tank – If possible, add at least five gallons to ensure the pickup tube is fully submerged.
2. Prime the system – Many late-model trucks (especially Power Stroke and Duramax engines) have self-priming systems or electric lift pumps. Turn the key to the “on” position (without cranking) and leave it there for 30 seconds. Do this a few times to help the pump push fuel through the system. To “cycle the key” with push-button systems, press the start button without having a foot on the brake.
3. Start the engine – It may take longer than usual or several tries. Don’t crank for more than 15 seconds at a time. If it starts and dies, repeat the priming cycle. The check engine light should clear itself after a few drive cycles.

For older Cummins trucks (pre-2003), you might need to manually bleed the fuel lines using the hand primer or by loosening injector lines.

If in doubt, hit the fuel station earlier rather than later. If you adhere to low fuel warnings, you still have several gallons of reserve and should be at no risk of actually running out of diesel.