07 5.9 ecm 5v sensor location

The sensor that's used for that is your rail pressure sensor I believe. It's bassically a check sum. Fuel pressure is not required.
Do you a have a gauge on ur fass. Is it pumping fuel?
Have you done a return flow.
I highly doubt it's your pump. However u say MOST of your injectors have been replaced. thats where I would start. Also check the relief valve on the rail. Is it making oil?? Probably worth a 25 dollar sample to determine that.
If all else fails it's
Most likely an injector.



Sent from AutoGuide.com App

This whole thing started with a stall and no start that led to a tow and a scan and a bad FPS. Replaced, ran great for a couple days. Then stalled and died and got restarted several times. Thought it could be FCA so replaced. Changed fuel filter. Ran for a couple days, then same problem. Towed, diagnosed at diesel performance shop, determined it was bad lift pump. Replaced with FASS. (no gauge) Ran great for a week, then threw a code and started lumpy, rough cold idle... went away after a few minutes. Did this for two weeks until I took it in today. Came up 0148, injector cut-out test showed no variation. They swapped out fca just to test, but wasn't the problem either. Recommend pulling injectors and checking return rates.
I'll try to test fps voltage, then look for the check relief valve and figure out how to test that.

You can search rail pressure relief valve and find out how to test that. With all that's been replaced your most likely needing to do a return flow.
Replacing the cascade over flow valve is a cheap way to rule out one problem. I believe they are about 60 bucks

Sent from AutoGuide.com App

I think I'll call the shop and ask them to do both. I am between houses and do not have all my tools and it's a pain. And even then, I'm only moderately capable of doing either, it's time really. Either way, it would be cheaper to have them do both than pull off the top and test my injectors for $600.
Oh, btw, FPS had 5.2v.

copelander said:

I think I'll call the shop and ask them to do both. I am between houses and do not have all my tools and it's a pain. And even then, I'm only moderately capable of doing either, it's time really. Either way, it would be cheaper to have them do both than pull off the top and test my injectors for $600.
Oh, btw, FPS had 5.2v.

Click to expand...

Yeah to test the prv is basically just taking off a fitting and lookin for fuel.
Good luck. Be sure to post results here.


Sent from AutoGuide.com App

I had a very similar issue, truck would randomly die when coming to a stop. Ended up being cross tubes weren't tight enough. Start with the simple stuff, its cheap and easy enough to just snug them up. Have you checked your rail pressure?

Okay, so I need to remove the breather cover, the CH cover and then use two wrenches to loosen cross hoses from injector tubes. Can I use wrench to tighten tube or do I have to track down tool #9015? And if so, where?

Well, that was fun. About 3 hours worth. I just removed breather cover, then cylinder head cover, and eventually the air intake manifold and heater to get to #2 injector tube. It was a little loose as well as #5 and I think #4. Tightened all, put back together and still no better.
I checked codes and threw four of them this time.

Still 0148, but also 0251 (Fuel Injection Pump Mechanical Failure Fuel Valve Feedback Circuit), 0088 (rail pressure too high), and 0193 (fuel rail pressure sensor high)

It runs the same as it did. After it warms up it'll eventually idle okay, but when I step on pedal there's is a hesitation for like 2 seconds and then it goes. At high speeds there is no problem.

:confused013:

Get a real scan tool, high end, on it and data record PIDS for REQuested RP, Measured RP, boost, TPS when it's running correctly and when it goes Dinky Dao.
post here.

sounds like intermittent leaking nozzles/pintles or inj. return valves. will show as low RP when it goes tits up.
can also be intermittent FCA or RP sensor wiring/connector.

hope you used a known accurate torque wrench on the connector tube nuts? or they're tits up ruined.

Out of necessity I bought a 24mm wrench to hold tube nuts while loosening connector tube nuts with 19mm wrench. Once off, I used the 24mm (or in the case of tube 2 a 15/16 socket) and tightened to about where the others were already, assuming (yes I know) they were plenty tight. I did not reef on any of the tubes. And when tightening the connector tube nuts I snugged them to about where they were when I took them off. No, it's not perfect, but it's what I had. It still runs the same as it did before.

Question: If my cp3 were bad would I still have high rail pressure problems? Does this sound like maybe a fuel return problem? I cracked the check valve while engine off and some fuel started to leak out so I retightened. The performance shop thinks it's the cp3, but it only has 32k miles on it.