I have just about given up on this truck.

The truck is not a daily driver and my problems started a few months ago with a faulty lift pump.

I upgraded the lift pump with the Dodge in-tank upgrade. It seemed to work fine at first.....then came a lack of power, stalling, and eventually hard/no starting. (second time I drove it (300miles) after the upgrade)

My research here seemed to point to a faulty fca. I replaced the fca.....but it made no difference.

I took the truck to the dealership for their 'expert' diagnoses, as guessing can get costly.
The dealership diagnosis said it was DEFINITELY the injection pump. I bought an injection pump, rail pressure gauge and injector line blocking nut.
While doing my own diagnosis with the injector line blocking nut, I became quite confused. It seemed like the engine was more likely to start once the fuel system had been opened.

I decided that it was not the injectors so I went ahead and changed the injection pump. Engine cranked for about thirty seconds and fired up. Continued to start it in the shop for the next couple days. It still wanted a full three seconds of cranking time, but it seemed to start.

Then on the third day still sitting in the shop........it failed to start again (obviously NOT the IP) Rail pressure shows about 1500psi when cranking........just like it did when it wouldn't start before the injection pump replacement. I now own the injection pump and sent the one I removed back for the core.

As I see it.......the only things left are the rail and injectors.

Any ideas?

Mike

 

It seems to sound like your cp pump not building pressor

 

what is a blocking nut? where is it located? did u put cp3 on urself?

 

Blown pressure relief valve? You can pull out the banjo bolt and tap for 1/8 pipe plug. Install plug and reinstall banjo. If blown it will not allow pressure to be built up enough to start.

 

I did put the cp3 on myself.

this is the blocking nut : Tester,Injector ISBe (Common Rail) found here http://hoeslidiesel.com/store/page13.html


What is CP pump?

Green......I would have to cut new threads in the rail where the pressure relief valve fits??

The starting is eratic. Sometimes it will start, other times it will not. Could the pressure relief valve work sometimes but not work other times?

I should also add that the injection pump I removed had a remanufactured tag with a mopar brand on it.....obviously it had been already replaced by the previous owner. (hope it fixed the problem for him and he didn't throw his money away like me)

Thanks
Mike

 

Everyone left?

 

Green.......I understand what you are saying now...I just had to think about it for a minute. I am kind of leaning toward that relief valve.....but I am pretty pessimistic about the whole thing now (possibly due to the dealerships' MIS-diagnosis costing me $)

Mike

 

I ran with the plug in the banjo for quite awhile. Now with the twin pumps I have the second pump feeding into the rail where the relief valve once was. It could also be that the injectors are bypassing to much fuel back to the tank, but I would rule out the relief valve first. If the relief valve tests good and you want to keep it operational just remove the plug.
Good luck!

 

thanks Green............I will plug that relief valve off tomorrow and see what happens.

Anyone know what is a good crank time for these engines? Once I get my problem figured out......I would like to see it start in less than three seconds crank time

 

My truck is up and runing in a second or so of cranking.Do you have any codes?There was a flash for long crank.Not sure what year models it applied to.Its been debated as to whether or not the relief valve is a one time blow or can reseat after blowing.Kind of a 50/50 mix of opinions.Plugging the banjo bolt is an easy enough check.You can also just remove the banjo bolt on the relief valve and gently push the return line to the side and visually check for fuel passing by the valve.If you try this you will need to dry the top of the valve out first and then crank and verify if its leaking(nothing should come out) and also keep in mind a decent amount of fuel will be flowing out the disconnected return line.I zip tied a ziplock bag on it to catch the fuel.

 

I would like to see my truck running within a couple revolutions as well. I have a few 25 year old mercedes diesels that start in less than one second in the cold i.e.- -10c

It is my opinion that an engine that starts well and idles well is usually a healthy engine

 

I have had the 0251 code a couple of times...and also ? 0480 and 0483? the codes in the 400s were related to the electric fan, which I noticed while changing the IP, the wires have been cut for some reason

the 0251 was related to the fuel system.....I have forgotten the exact description

 

Did the new cp-3 come with a fca? The 0251 is an fca code.

 

Got this off another site


P0251 - CP3 Pump Regulator Control; Injector Pump Fuel Valve Feedback: The ECM detects a discrepancy between PWM supplied to FCA and PWM returned from FCA.

Possible causes:
- Intermittent condition
- Fuel Control Actuator
- Return wire open from FCA to ECM
- Supply wire open from FCA to ECM
- Supply circuit shorted to voltage
- ECM

 

The new cp3 came with a new fca. I just put a new fca on the old cp3 a few weeks ago. The code I erased a couple days ago DEFINITELY re-appeared after the new fca was installed. But the code could have been there before I installed the new injection pump........which came with another new fca installed.

This 0251 code was present before I installed the new fca. I erased the code once the new fca was installed, then it re-appeared again. I'm not exactly sure when it re-appeared.