I have a 2002 f 250 superduty turbo diesel if I prime it a few time I can get it started but it won't run long fuses and relays were good I found the fuel regulator was bad replaced that but it's still doing the same thing could it be the fuel pump if so witch one

If you prime it and it runs till the prime is gone I would think it has something to do with fuel. The fuel pump could run but not put out enough pressure. I had a 88 blazer I was able to hook up a fuel pressure gauge by the left rear tire and found low pressure. I fixed the car when I changed the fuel pump. It could also be a fuel pump fuse or relay. If the pump is running it may rule out fuse or relay. Here are a bunch of video which has a good bit of info. Some of it may help. If you think it is a relay you may be able to swap relays with something else, if they are the same relay. Make sure what you swap with is not a vital part. I have found something like swap fuel with AC relay something like that. I actually went to a junk yard and found several relay for a dollar each one time. At that time I did not know anything about how to check them. They may not be a dollar now. Hope this helps
https://www.youtube.com/watch?v=MO2cDvDwPp0
https://www.youtube.com/watch?v=7syxAWw6Q-s
https://www.youtube.com/watch?v=X1bdHQ0HbdA
https://www.youtube.com/watch?v=pRWppSEogeo
https://www.youtube.com/watch?v=HGdOwERGoe8
https://www.youtube.com/watch?v=WdldGv40dS8

you found the right place buddy.. i know a lot of websites for repairs and manuals that can really help u..
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There is only a few cars fitted with an ancient petrol injection system that needed any priming.

Diesel engines mostly need the injection system priming but petrol injection systems do not.

Lots of cars use a system where the fuel pump runs for a couple of seconds when the ignition is switched on and that is all the time it takes to prime the fuel system. After a couple of seconds the fuel pump switches off and waits to restart when the engine is cranked.

As priming the system takes only a couple of seconds some manufacturers don't bother with the brief priming run of the pump and just have the pump start when cranking.

Could be faulty supply, fuse, pump relay or the pump itself.
If the car is fitted with an immobiliser, perhaps that is the problem.

check engine immobiliser and crank position sensor . Run fault codes and replace faulty units.

The fuel system needs to to have the air bled out of it. I suggest having a technician do it for you to prevent serious injury and damage to the vehicle.

fuel injection pump is failin or has issues--getta haynes manual for pro car maintenance

sounds more like the ECM than a relay, to me.

Hi,remove fuel filter fill it this should get ya enough fuel so it will start and continue to pump fuel ,riding system of air and system will be primed,Good luck.

Charge the batteries. take a Reading to make sure that you are getting almost 14v to both batteries. If it is not charging then take the alternator back off and have them check it. you might have bought a bad one. There is a way to test the glow plus with out taking them out. ( Take a piece of wire long enough to reach all the glow plugs from the battery. unplug the glow plug wire.If you touch the end of the glow plug with the hot wire it should make a little spark. if no spark then the glow plug is bad. do this to each one, but one at a time)

If it has glow plugs or an intake heater you will need to disable the circuit. Then you can use a small amount of ether to spray into the air cleaner.!!! If you spray too much and/or Dont disable the circuits you can damage the motor!!! When you spray the ether, if the engine starts and stalls then its not getting fuel. This could be related to the fuel pump, injection pump, the fuel system loosing its prime(fuel line leak), fuel shut-off valve or solenoid. If it doesn't start then it could be related to your timing, valves or maybe compression.