07 5.9 still acting up

[DickieGreen]

Hello folks im still needing help just a little review bad fuel pulled tank flushed tank replaced in tank pump blew lines out from tank to underhood filter housing replaced filter no start injectors tested replaced all 6. crank about 6 to 8 sec would start after driving about 20 min if you let off fuel it would die the shop sdaid bad high pressure relif valve replaced it back to shop then they said cp3 pump so i replaced that same prob it cranks and starts after about 6 sec idles good after warms up and driving if you let off fuel it dies will not start without starting fluid unless you let it set wondering if some trash got to new injectors thanks for any help

 

[DickieGreen]

oh yea one code that keeps showing is p0148

 

[p-Bar]

Did you flush past the fuel filter? That would have been my concern. Random parts replacement will get you their but the mechanics need to diagnose the problem better. Are they using a DRB III or equiv. to see rail pressure ect. . ?? po148 fuel delivery error message . Wait for some others to chime in. What did you do for new injectors ? rebuilds? who's?

 

[DickieGreen]

when i changed injectors i blew out injectors lines but not the rail not sure on scanner just know it was snap on he said he could check all that and injectors were bosh rebuilt by taylor diesel in memphis tn and im thinking about towing truck to them and let them run scan thats all they do is diesels
Thanks for the info also truck feels weak

 

[p-Bar]

The Bosch remans are more bulletproof than the ones remaned by these rebuild co. . Need to see what your rail pressure is and monitor it . Good luck keep us posted . Have been told if you have some miles on the engine it's a good idea to change out the pressure relief.

 

[DickieGreen]

Thanks p-Bar

 

[p-Bar]

Your welcome. Did they replace the fca? It's located on the back of the CP3. Not sure if the new one came with one. Other post indicating retorque crosstubes , missing copper washer for injector or old one wasn't removed. Were these guys cummins mechanics. The code is from pressures not agreeing with one another (what's on the rail) and what the computer thinks

 

[DickieGreen]

Yes there was a new fca on pump taylor diesel works on cummins the guy that said replace pump has shop and works on all diesels

 

[cerberusiam]

Now, take the injectors out and use them for a core on a set of NEW to solve the problem. Bosch remans are enough of a gamble, anybody elses are really bucking the odds.

 

[g_dog1]

I didn't think failing injectors would through a code unless it was at the injector coils. With P0148, maybe when the ECM tells the FCA to give the CP3 more fuel, it isn't registering with the rail pressure sensor. Maybe your lift pump is failing. Did you manage to see what pressure into the CP3 was (after the stock fuel filter and on the inlet side of the CP3?

 

[AllianceDiesel]

Failing injectors wont throw codes but high return will cause hard starts. One thing to remember, lift pump is measured by flow not pressure. Without knowing rail pressure it is hard to diagnose

 

[p-Bar]

Injectors installed wrong will

 

[cerberusiam]

Injectors mechanically failing will cause the P0148, it is part of the toruble shooting tree. You have now replaced a bunch of parts that were probably just fine IF you had a GOOD set of injectors. Buying reman injectors from Injector-Schmucks-R-Us is just not going to end well. Time after time after time this happens. BUY NEW INJECTORS OR SUFFER THE CONSEQUENCES.

Even Bosch is not immune to the problems. Have now replaced 2 ot of a set of 6 in a little over a year, NOT a good sign.

 

[AllianceDiesel]

Ive never had a single problem with the bosch rebuilds I have installed. (Knocking on wood) Ive probably done a dozen sets from my current bosch supplier. I agree on his symptoms, if you replace something with a questionable part it useually bites you right in the rear

 

[jfluffy2]

Did you clean/replaced the cross over tubes?

 

[Prairie Dog]

Reman (even Bosch) injectors have a terrible record here on this forum. So much so that I would never even consider them.
Cerb is right as usual, go with new.

 

[PWong]

One thing to remember, lift pump is measured by flow not pressure. Without knowing rail pressure it is hard to diagnose

If the CP3 is working then any positive lift pump pressure before CP3 would indicate that the volume of fuel delivered to CP3 by lift pump is good.
A good lift pump pressure can be a good substitute for testing the volume of fuel pumped by the lift pump.

 

[cerberusiam]

If the CP3 is working then any positive lift pump pressure before CP3 would indicate that the volume of fuel delivered to CP3 by lift pump is good

That is not strictly true either. The CP-3 will work fine to a point even when it is drawing its own fuel or LP is just maintaining 0 psi. 5 psi an over at ANY load and rpm is adequate for stock fueling, 7 psi at idle and 1 psi under load will likely set DTC's and have physical manifestations. Even 0 psi at low load criuse will work but it is not good for the CP-3.

The whole story about flow not pressure detemring LP performance was nothing but a way to avoid warranty work and responsibility. There is no good way to adeqautely test flow without some expensive precision equipment. A flow number is totally meaningless as demange changes dynamically based on inputs and excess is constantly being returned to the tank. Without measurementson each and every possible fuel route it wild guess at best. Pressure at the CP-3 is the only comprehensive way to assess LP functionality. It is a known number that can easily be monitored and assessed.

 

[PWong]

Pressure at the CP-3 is the only comprehensive way to assess LP functionality.

Thanks for the conclusion.