Hello,
2004.5 2500 4 door 4x4

I will keep this as short as I can. I am having a severe loss of power when towing. Hills I used to tow a fifth wheel up at 65 now at 30 mph. The truck always shows the p 0148 code and occasionally when towing, the truck will cough and completely cut out for a few seconds then the check engine light will come on and then show the p 0251 code. The light will remain on for a day or two then goes back out.

I've had the dealer look at it and they are telling me that all of my injectors need replaced. They haven't checked the injectors themselves but have done an "in and out" test and everything checks fine so it must be the injectors. I'm not sure I'm ready to spend $$$$$ on their hunch.

A few years back, I installed an Edge EZ and almost immediately started having injector problems. I took it off after about six months out of frustration and have since ran bone stock. Could this problem be a residual from the Edge EZ? Any help is greatly appreciated.

 

I forgot to mention that when I'm towing up hill with the window down I can hear what can best be described as a spark knock sound. I know it can't be spark knock.........this is just a sound description.

 

Below is the information per another thread
Pulled from the 06 service manual:

P0148-HIGH PRESSURE COMMON RAIL (HPCR) CHECKSUM
For a complete wiring diagram Refer to Section 8W.
² When Monitored:
While the engine is running.
² Set Condition:
A deviation between the fuel pressure set point and the actual fuel pressure.
Possible Causes
OTHERS DTC’S PRESENT
FUEL LEAKS
FUEL CONTROL ACTUATOR
FUEL PRESSURE SENSOR
CASCADE OVERFLOW VALVE
CHECK VALVE DAMAGED OR BLOCKED
FUEL RETURN LINES OBSTRUCTION, DAMAGE, OR DEBRIS
LIFT PUMP FLOW
AIR IN FUEL SYSTEM
LEAKING FUEL INJECTORS OR HIGH PRESSURE CONNECTORS
PRESSURE LIMITING VALVE
HIGH PRESSURE FUEL PUMP
INTERMITTENT CONDITION

 

p0251 is related to your CP3 injection pump. I had the same symptoms as you, cutting out for a second and flashing CEL for a few days. I was going to replace the FCA myself to see if that helped but the dealer ended up putting in a new CP3 under warranty. As stated above it could be a lot of things, rail press sensor, popped rail relief valve, FCA/CP3. You would probably have other symptoms if it was injectors (white smoke, fuel in oil, etc.) other than those codes and most injector problems don't even throw codes! You out of warranty? Too bad you can' trust the dealer because knowing your actual v demand rail pressure would tell a lot. I ended up installing a rail press guage and low press fuel after my ordeal to keep an eye on these things. ohh and its always suspicious when they say all 6 injectors need replaced! wheres the kill test or % contribution test results that are making them so sure its injectors??

 

Thanks guys for your responses. After reading bradler's post and several conversations, I am on the hunt for a system that will moniter fuel pressure, EGT, boost and so on to see if I can begin to understand what is going on and hopefully find the problem. What type of system do you guys recommend? I've heard of Smarty, Banks, Edge and Quadzilla. Are one of these better than the rest? Thanks again.

 

My cousin has the same truck we do and had similiar issues and he needed a new CP3. I had similiar issues and needed a new CP3 and after they installed it i still had the same issue and we put it on a dyno. well lo and behold we got a rebuilt CP3 that wouldn't maintain the pressure under load. Went back to shop and got another CP3 replaced with another unit and truck runs fine. My truck would run great alone but under loads it felt like we were losing ground. I can's say if this is your issue but the symptoms sound exactly like the ones we were having and it was fuel related in both our trucks.

 

I have an in-tank lift pump because mine went out at about 50k miles. Is there any way to test the lift pump so I can either rule it out or replace it? I am convinced that I have a fuel delivery problem and that it's not the injectors. Chances are it's the CP3 as Skeetsbo is suggesting but before I go replacing it I would like to rule our everything leading up to it. What about the FCA; Any way to test that? thanks everyone for all you input. This forum is way more helpful than my dealer.

 

Read tsb here may help diag

https://www.dieseltruckresource.com/....html?t=267822

 

I would think there is some kind of pressure test you can do on the line from the lift to the cp3. My lift pump was in it's original spot and I had a fass system on my truck that's in lieu of my factory lift pump. When they dyno'd my truck as the load increased you could see that it wasn't supplying the fuel on the computer screen. It was way below what the truck was needing in the reading. The fact that my truck ran great w/o a load kind of supported that the lift pump was getting the fuel to the CP3. When it was under demand was when it fell off and that's how they diagnosed that the CP3 was the culprit. The cp3 job is to maintain the pressure in the rail by boosting the pressure in the pump. I'm not a real techy guy but that's how we found it and I hope I explained it well enough so you could understand. There are others on here whose vast knowledge will be able to offer up a better explanation and may be able to help you identify your issue better.

 

AZ hunter1 I don't know why I didn't think of this sooner. Southwest diesel on 27th avenue is one of a very few authorized bosch rebuilding center for our CP3. they should be able to diagnose the issue for you and isolate it. They have been in business for years and have a good reputation.

 

This series of videos does a pretty good job of showing how to diagnose injector issues.

http://www.youtube.com/watch?v=eMbB4UMZMpI

 

Have them do a pressure limit valve test. The Pressure Limiting Valve will most likely need to be replaced. There is also an updated ECM which should also be replaced (unless the ECM had been replaced prior with part number 05191829AA / R5191829AA or newer) to prevent repeat PLV failures. The service kit for a revised ECM and a PLV is P/N 68003886AA.

 

Update-

I hate it when people don't follow up with these things so here goes.....

Thank you to all who offered help. I decided to try another shop here in Phoenix, Deer Valley Diesel, and they diagnosed the problem as the #1 and #2 fuel injectors. I had them go ahead and replace them and it fixed the problem. I am back to pulling the TT up the hills at a respectable speed. Pulled the rim going to Woods Canyon Lake (for those of you who are familiar with AZ) at 61 mph with the air on. Sure is nice to have my truck back running like it should.

 

We camped at Aspen Campground a couple weeks ago, it was sure busy. Glad to hear you are back in action, and I will keep Deer Valley in mind if I need anything..