[apcoleman7.3]

I have a 97 7.3 and my fuel gauges haven't been reading correctly lately. Today when I was leaving my house, about a block down the road my truck ran out of fuel and sputtered out and I had to have a buddy tow me home. I am not the type to run her down to empty however my gauge was reading incorrectly. I switched to the back tank at home (which is full) and have tried cranking on her but did not start and batteries died. I have tried watching videos and such however I do not have conventional fuel bowl so I am confused. I have a crude diesel regulated return kit on her (fuel bowl delete).
Here is a picture of my setup. The fuel pressure gauge is where the bowl used to sit and the filter is by the fuse box.

 

[JGK]

Mine is a super duty. But yours is modified. Do you have a pump, an electric pump, prior to that filter? Or is your pump the mechanical one on the engine, that I believe the OBS Power strokes have? I without knowing the full configuration of your system, it’s difficult to advise, but you can start with determining if your filter is full. Simply back it off and if it is not full, fill it up with fuel. Charge your batteries and try again.

 

[apcoleman7.3]

Mine is a super duty. But yours is modified. Do you have a pump, an electric pump, prior to that filter? Or is your pump the mechanical one on the engine, that I believe the OBS Power strokes have? I without knowing the full configuration of your system, it’s difficult to advise, but you can start with determining if your filter is full. Simply back it off and if it is not full, fill it up with fuel. Charge your batteries and try again.

I have the stock mechanical pump. I have determined that my pump seems to be working and it seems to be filling up the filter. I have tried charging my batteries up and cranking it with the filter full, but no luck. I checked the fuel tank selector switch, it seems to be working. The rear tank is close to full. I was under the impression that there was air in the lines, which there was, so I put some air in the tank with my compressor to try and push the air out through the filter, and one big bubble came out and now there is fuel in the filter as there should be. However the truck still won't start. Thanks

 

[apcoleman7.3]

I have the stock mechanical pump. I have determined that my pump seems to be working and it seems to be filling up the filter. I have tried charging my batteries up and cranking it with the filter full, but no luck. I checked the fuel tank selector switch, it seems to be working. The rear tank is close to full. I was under the impression that there was air in the lines, which there was, so I put some air in the tank with my compressor to try and push the air out through the filter, and one big bubble came out and now there is fuel in the filter as there should be. However the truck still won't start. Thanks

Wondering if maybe it could be a bad CPS or if maybe the fuel pump burned out with all the cranking I have been doing today?

 

[JGK]

I doubt if cranking would burn out the fuel pump. Have no experience with these pumps and don’t know if pumping with an airlock can damage them… But I seriously doubt if that fuel pump is the issue. Suspect airlock elsewhere. But though I have experience with a variety of diesel engines, this particular Engine is not one of them

 

[bugman]

I'd say that you need to find the valve to purge the air out of the system

 

[apcoleman7.3]

I'd say that you need to find the valve to purge the air out of the system

I put a new CPS in just to be safe. I think this black valve on the filter purges the air out. It has to be because there are no other ones to my knowledge. Thanks

 

[dieseldogtom]

The black valve look to be nothing more than a simple on/off valve (shut off valve) likely installed in an attempt to make fuel filter changing less messy. (though I wouldn't think it really necessary with the location being so high above tank. Unless to stop pressurized system from pumping fuel through).

 

[JGK]

Did you install this fuel system, or did you purchase it like it is? After rereading your original post, I’m wondering if it’s possible that you did not actually run out of fuel… But rather developed a fuel line crack. Was also wondering if you have ever changed that spin on filter because I’m having a hard time imagining how you would refill the spin on cartridge, unless you just fill it from a can before spinning it on. I also wonder if there is a check valve between that filter housing and the tank or tank selector valve.

I would definitely give your fuel lines a very very thorough examination, particularly between the pump and the filter. Right now it appears that whatever was causing your initial loss of fuel pressure (you didn’t actually define your original fuel pressure issues)then caused your engine to quit, and perhaps your assumption that that fuel tank was out is leading you down the wrong path. I am suspecting that all of your symptoms from your original Observation of unusual fuel pressure, to the engine dying, to not being able to get it restarted, are symptoms of a singular problem, which may be or damage fuel line, for now that I have a different picture from whole scenario… albeit perhaps not entirely accurate… That everything may point to the fuel pump.

 

[JGK]

Also, you cannot purge air by opening something prior to the pump, unless you have a substantial head of fuel, which you clearly do not.

 

[JGK]

1) changed all filters.
2) inspect all fuel lines and fittings
3) purge air from the system… This may require system modifications, or a shop vac with the hose in the tank fill while hooked up to the discharge of the shop vac to generate some fuel head from your tank
4) if you do use the shop vac procedure, strongly consider moving the filter to the frame rail sometime in the near future, and add another ball valve on the suction side of that filter housing like you have presently on the discharge side. Would probably also not use the port as they are being used now but just do a straight pass through