Engine code P0191

[Deleted member 995608]

Started to act up on start up a few weeks back but now I have the code P0191. Once it starts, it's fine for the rest of the day.

Changed the filters on the FASS and the engine mounted filter. I OHM's the injectors today and found nothing out of the ordinary (Cummins re-mans w/ 50K + miles). I unplugged the FCA and it started fine and then gave me the code P0251. I also checked the injector harness and the fuel line fittings for leaks and nothing found.

I'm trying to sell the truck so I hate to throw parts at it but it does need to operate correctly. At this point, I'm thinking its the FCA or maybe the rail pressure sensor.

Any ideas?

 

[Deleted member 995608]

Just had a buddy bring over his scanner and it specifically says the "fuel rail pressure sensor" is faulty. I'll order that part first.

 

[JJPage]

JH you may want to check out the fuel rail press relief valve before ordering parts, see if it's leaking. In fact while you had the FCA unplugged would have been a good time to check it's integrity.

 

[Deleted member 995608]

JH you may want to check out the fuel rail press relief valve before ordering parts, see if it's leaking. In fact while you had the FCA unplugged would have been a good time to check it's integrity.

If the relief valve is leaking, would I see a visible fuel stain or wetness?

I how do I test the FCA? Ohm it? Hit with a hammer?

Thanks Jes. Best wishes.

 

[cerberusiam]

P0251 is the FCA not reacting correctly, P0191 is range performance on the rail pressure sensor. With those 2 codes start checking battery connections and grounds plus make sure your batteries are good. They frequently show with connection issues.

The PRV can be chcked by removing the banjp bolt on top of it and bagging the line (it returns a LOT of fuel), drying the well out with cleaner and air, running the engine at about 1000 rpms and unplugging the FCA. If it stays dry it is good, if you see fuel seeping it is bad.

 

[JJPage]

The PRV can be chcked by removing the banjp bolt on top of it and bagging the line (it returns a LOT of fuel), drying the well out with cleaner and air, running the engine at about 1000 rpms and unplugging the FCA. If it stays dry it is good, if you see fuel seeping it is bad.

Do not look into the valve while testing, if it is leaking, the high pressure fuel could really cause you some damage.

 

[Deleted member 995608]

Thanks fella's