Ran Out of Fuel: Why a Diesel Will Not Just Restart, and What to Do

The direct answer: a diesel that has run its tank dry has pulled air into the fuel system, and adding fuel does not remove it. The system has to be primed — filled and bled using the engine maker’s procedure — before the engine will start and keep running. Do not crank it continuously hoping it will catch: that overheats the starter, flattens the batteries and runs the fuel pump without the fuel that lubricates it.

First: can you keep driving?

It is not going anywhere until it is refuelled and primed, and most are restarted where they sit. Stop cranking and call if it will not start after priming, or starts and dies repeatedly. (916) 571-8888. If you are stopped in or near traffic, hazards and warning devices come first: see our warning triangles guide.

What to do

1. Put in enough fuel. A few gallons may not reach the pickup, especially on a slope or with dual tanks joined by a crossover line. Add a meaningful amount, to both tanks if there are two.
2. Prime the system the way the engine maker specifies. Depending on the engine, that is a hand primer pump on the fuel filter housing worked until it firms up, or an electric lift pump that primes through a set number of key-on cycles. The procedure is in the operator’s manual.
3. Crank in short attempts with pauses between. Follow the starter duty limits in the manual.
4. Once it runs, let it idle until it smooths out. Rough running and stumbling for the first minute is the last of the air.
5. Check for leaks at anything you opened, and watch for a water-in-fuel or low fuel pressure warning.

What not to do

• Do not crank for long stretches.
• Do not use starting fluid. Diesels with intake heaters or glow plugs can ignite it in the intake, and it can damage the engine.
• Do not pre-fill fuel filters with unfiltered fuel unless the engine maker’s procedure says to. On modern high-pressure systems, fuel poured into the clean side of a filter goes straight to the injectors unfiltered.
• Do not loosen high-pressure fuel lines to bleed a common-rail engine. The pressures involved are dangerous, and those systems are not bled that way.

If it still will not start

• Still air-bound — not enough fuel in the tank, a primer pump that is not sealing, or a loose filter letting air in on the suction side.
• Plugged fuel filters. Running a tank to the bottom draws up water and sediment that then blocks the filters. They may need replacing before it will run.
• Batteries too low to crank at speed after the attempts so far (battery, alternator or starter).
• Something else stopped it. If the gauge showed fuel when it died, the problem may never have been an empty tank: see truck stalling and truck won’t start.

If it ran out sooner than it should have

• A fuel gauge or sender reading high
• Dual tanks not equalizing — a blocked or kinked crossover line, a closed valve, or a plugged tank vent leaves fuel in one tank that the engine cannot reach
• A fuel leak from a line, the tank or the filter housing
• Fuel theft while parked
• Fuel economy that has dropped (fuel economy decline)

Afterwards

Have the fuel filters checked or changed if the tank was run to the bottom, and drain the water separator; our water in fuel page shows how. An empty DEF tank is a different problem with its own warnings and speed limits: see DEF derate rules.

How we help

Running out of fuel is one of the faults most often dealt with where the truck sits: priming, filters, and a check that nothing else caused the stop. Tell us the engine, whether you have added fuel and how much, and what happens when you crank. See mobile truck repair and emergency roadside assistance.

Common questions

Why won’t my diesel start after I added fuel?

Air in the fuel system. The pump cannot move air the way it moves fuel, so the system has to be primed before fuel reaches the injectors.

Does running out of diesel damage the engine?

Once, primed correctly, usually not. The risks are from what follows: long cranking, sediment and water drawn from the bottom of the tank, and a fuel pump run without fuel.

How much fuel do I need to add?

Enough to cover the pickup with the truck sitting as it is. On a slope, or with two tanks and a crossover, that is more than a couple of gallons.

Do I need new fuel filters after running out?

Often, if the tank was run completely dry. If it starts and then loses power under load, restricted filters are the first suspect.