I have a 2002 F-450 crew cab 2wd automatic 7.3 diesel with 298k on the body and about 120k on a Jasper engine. About a month ago I started it in the morning to let it warm up. Went to make coffee. Came back and it had died. It was low on fuel and I didn't pay attention. Played hell getting it primed back up. Now if I don't let it warm up for twenty minutes it won't run worth a flip and has been dying out. Changed fuel filter. Unplugged ICP. No change. When I crank it it will turn over for about thirty seconds then oil pressure gauge moves, then engine starts to run very roughly. It will die. I repeat a few times. It will eventually start and start and stay running. Blows whitish grey smoke until it warms up. No loss in power till CEL comes on. Still not too much loss. Sometimes it takes a long time to get it running. Sometimes it will die after I get out of the driveway if I don't let it warm up. Truck was serviced maybe 3000 miles ago. No water in fuel. New fuel filter. New air filter. It is a company truck. I work for a small company building cell towers. Don't wanna spend money at dealer or high dollar shop if I don't have to. Any help would be appreciated.

 

sounds like low pressure pump issue (pickup or supply pump in tank) shop should b able to check fairly cheap test port is next to filter on left side i think spec is 40-50 psi off hip could be wrong

 

This sounds like it may be a low oil pressure issue. It should not take 30 seconds of cranking before the oil pressure gauge moves. How many miles since the oil change? Check the engine oil level and in the HPOP reservoir. If the hpop reservoir runs low, it will pick up air and cause symptoms similar to what you expressed.

You can try parking your truck on a steep slope with the engine down slop. See if you develop oil pressure quicker. If this is true, then you have a problem with the oil pickup tube seal.

 

I didn't start having problems until I ran out of fuel. I'm thinking about dropping the tank and checking out the pickup and filters in it.

 

Before you drop the tank, you should check the fuel pressure. Here is a link to a thread that I show how to check fuel pressure: https://www.ford-trucks.com/forums/1...rt-help-3.html see post 44 and 47. You should have 60 psi.

If I read your post correctly, it seems odd that if it is a fuel delivery problem that it only runs poor for the first 20 minutes. Checking your fuel pressure will be the best way to diagnose fuel delivery.

Is it possible that it is just coincidental that the problem occurred when you had low fuel, but you did not truly run out? I am just throwing this out as a possibility. It throws the cel on, so you should get it scanned and see what the dtc is.

 

It ran out. I had to put three five gallon cans of diesel in before it would prime back up. It's been occurring ever since that morning.

 

Okay. This is also odd. I have run 7.3s out of fuel before (including a 2002 f-450). All I had to do was add a couple gallons and cycle the ignition key on a few times to let the system prime itself. The trucks would always start right away with no troubles and maybe a slight rough running for less than a minute, and no smoking. This is the reason why I suggested that maybe it is something else. Post if you get it figured out. I would like to know what caused your problem.

 

Checked HPOP reservoir when truck was cold and hadn't been run since night before. About 1 inch from top. Filled up. Cranked right up. Let it warm up. No CEL. Drove to parts store. Had about 1/2 tank fuel. Bought some diesel purge. Couldn't pull up any codes. Put in diesel purge. Topped off tank. Drove around for about an hour. Went to Wally World for about an hour and a half. Started right back up. Drove home. We will see what happens in the morning.