Recently had a customer come in. Said they had a diagnosis needing Injectors. Replaced Injectors, and came up with a fuel delivery error p0148. Replaced fuel rail pressure sensor, pump in tank. Ran some fuel pressure override tests and went from good pressure to 0%. After an injection pump replacement, it ran great. Ran for about 15 miles and the code came back, and it completely shut off and had no pressure at all. Couldn’t pull its weight back to the shop, and would die going uphill again. Any ideas? Bad pump?

Hook up a live data tool and watch the rail pressure. If the rail pressure start to slide downward as the engine warms up then you have a rail leak. Most likely the crossover tube is not seated properly in an injector or the crossover tube is loose slightly. I've seen this before. The one I dealt with the rail pressure was good cold as it warmed up it continued to slide down till it would no longer run (below 4k PSI). Let it sit and cool down the pressure returned. We started checking crossover tubes... Bingo! The truck has been running since. 

We sell quite a few pressure relief valves here at the dealer. mopar# 5093113aa they are expensive but like i said they fail quite often it seems like

Is there another name for it so I can figure out what PRV you are talking about? Thanks for sharing.

I second that the rail pressure limiting valve could be the culprit for low rail pressure. Other items I've seen cause issues on common rail diesels, as @Mopar1973Man mentioned cross over tubes, restriction in fuel supply lines from the tank, poor lift pump performance, plugged fuel filter, bad fuel actuator on the pump.

 

Being in a shop I've seen my fair share of pumps being junk out of the box. I just worked on a 03 Cummins 2500 today that had a weak in tank lift pump that was exhibiting the same symptoms you describe. It had a 2 week old Napa lift pump the was the issue. I was seeing -15 inhg vacuum at the CP3 when everything warmed up and the engine barely able to run. Another new Napa in tank lift pump fixed it.

I've heard that in-tank fuel pump you should look for Delphi they seem to be the better brand of pump typically for gasoline or diesel.

43 minutes ago, 04Mach1 said:

Other items I've seen cause issues on common rail diesels, as @Mopar1973Man mentioned cross over tubes, restriction in fuel supply lines from the tank, poor lift pump performance, plugged fuel filter, bad fuel actuator on the pump

 

Oh yea we see alot of poorly maintained trucks. Gotta change those fuel filters. I cant tell you how many times we see trucks come in for performance issues and they leave after paying for some diag work fuel filter(s) and a bottle of CRC diesel fuel therapy. (Napa number 05232 our tech swears by it for whatever reason). And these filters are so fine they dont take much to clog.

5 hours ago, 2000Ram2500 said:

 

Oh yea we see alot of poorly maintained trucks. Gotta change those fuel filters. I cant tell you how many times we see trucks come in for performance issues and they leave after paying for some diag work fuel filter(s) and a bottle of CRC diesel fuel therapy. (Napa number 05232 our tech swears by it for whatever reason). And these filters are so fine they dont take much to clog.

Plus those who skip on the maintenance also buy the cheapest fuel possible which usually is dirty and has a lot of water in it compounding the lack of fuel filter replacement.

 

My favorites are those that spend $60k on a truck then complain about the cost to maintain it. I had a guy in the shop on Monday with a lightly used low mileage 2012 Ram SRW 3500 with a seized VGT upset because I charged him $435 to install his used unknown HE351VE turbo. Then he got upset because I only gave him a 30 day warranty on my labor and nothing on his supplied part. 

Kind of why I do the double stack filter setup. AirDog 150 with Donaldson 3um filter and then the stock filter can is still there and I've got a 7um filter in there. So no matter what I've got a better chance of keeping dirt and water out of the injection pump and injectors. I will not buy the cheapest fuel either. I typically stay to either name brand truck stop that sell high volumes of fuel or name brands like Chevron. No mom and pop fuel stations for me. 

I need to get a better lift pump for this reason. Its got a big line on it and I was told by the previous owner its a Fass but no built in filter it just has a real basic strainer cut in line before the pump. But I only used the factory filters since I work there it only makes sense. Cummins oil and fuel filters which is actually fleetgard. Fuel same thing now anyways but living in CA its hard to spend around 4 bucks a gallon for the good stuff when all your doing is city driving getting not the greatest mileage to begin with. Now I get better stuff. Still no Chevron but i stay away from the real cheap places and mainly go to costco or maverick