2006 2500 Laramie, mileage loss.

[DanBarfknecht]

At 120,000 miles engine was producing white smoke at start up. Diesel Specialists of Green Bay Wi. found metal particles in fuel filter, said pump in tank was coming apart. Replaced tank pump, high pressure rail pump, and injectors as some injectors tested bad and concerned about filings in high pressure pump. $7000.00 ouch! Fuel mileage used to be up around 20 mpg in warm weather without load on truck. Since that work was done the best I have been able to record is 15 mpg. Mechanic said it sometimes takes up to 20,000 miles for things to settle in, at 25,000 with no increase in sight. Mechanic doesn’t have any answers for me. Thoughts?

 

[Ozymandias]

What injectors did you buy?

 

[DanBarfknecht]

Bosch certified reman pump and injectors and new Bosch crossover tubes

 

[Ozymandias]

Sounds good.
Did your mechanic install the CP3 phased like it is supposed from Cummins?
Some indys don't watch out for this and think it doesn't matter for a common rail.

 

[AH64ID]

At 120,000 miles engine was producing white smoke at start up. Diesel Specialists of Green Bay Wi. found metal particles in fuel filter, said pump in tank was coming apart. Replaced tank pump, high pressure rail pump, and injectors as some injectors tested bad and concerned about filings in high pressure pump. $7000.00 ouch! Fuel mileage used to be up around 20 mpg in warm weather without load on truck. Since that work was done the best I have been able to record is 15 mpg. Mechanic said it sometimes takes up to 20,000 miles for things to settle in, at 25,000 with no increase in sight. Mechanic doesn’t have any answers for me. Thoughts?

Hand calc’d mileage? Or going off the overhead readout?

 

[DanBarfknecht]

Sounds good.
Did your mechanic install the CP3 phased like it is supposed from Cummins?
Some indys don't watch out for this and think it doesn't matter for a common rail.

Please explain CP3 phased? Then I will call and find out

 

[DanBarfknecht]

Hand calc’d mileage? Or going off the overhead readout?

Both, mine isn’t too far off.

 

[AH64ID]

Both, mine isn’t too far off.

No 3rd Gen is accurate or consistent, and no truck is accurate with two different sets of injectors. If you’re using the overhead more than hand calc then that would explain the “loss”.

The computer doesn’t measure flow, it goes off what it thinks it’s injecting based on the duration tables. Those aren’t that accurate, hence the wide variety of error on a 3rd Gen. used injectors flow more than they did new, which means that the truck is using more fuel than it thinks so the mpg readout goes high. New injectors get installed and they flow less fuel, so the truck thinks it’s using more fuel. The mpg’s could be the exact same between the two; but there can be a huge difference in the reading.

 

[DanBarfknecht]

No 3rd Gen is accurate or consistent, and no truck is accurate with two different sets of injectors. If you’re using the overhead more than hand calc then that would explain the “loss”.

The computer doesn’t measure flow, it goes off what it thinks it’s injecting based on the duration tables. Those aren’t that accurate, hence the wide variety of error on a 3rd Gen. used injectors flow more than they did new, which means that the truck is using more fuel than it thinks so the mpg readout goes high. New injectors get installed and they flow less fuel, so the truck thinks it’s using more fuel. The mpg’s could be the exact same between the two; but there can be a huge difference in the reading.

Thanks, I will do paper and pencil for a while.

 

[Ozymandias]

Please explain CP3 phased? Then I will call and find out

It means the CP3 sits in a certain position to the crank so that the pump stroke of each of the 3 pistons falls together with an injection event. This way the rail pressure is more steady, otherwise it would be fluctuating up and down.
The FSM tells the mechanic how that is accomplished.

 

[AH64ID]

It means the CP3 sits in a certain position to the crank so that the pump stroke of each of the 3 pistons falls together with an injection event. This way the rail pressure is more steady, otherwise it would be fluctuating up and down.
The FSM tells the mechanic how that is accomplished.

I believe it also creates a quieter pump.

 

[Ozymandias]

Jep, it is important in several ways.

 

[BigPapa]

I've often wondered about this pump phasing. As you know, I'm certainly no CR expert, my experience is with the buses.

I've looked in our Cummins S/M's from '06 to '09's, and in all of them it shows this:

Is there something different about the Cummins in the Rams that requires this phasing? I've asked our good techs about it and they all say they've never heard about phasing the pump.

 

[AH64ID]

I've often wondered about this pump phasing. As you know, I'm certainly no CR expert, my experience is with the buses.

I've looked in our Cummins S/M's from '06 to '09's, and in all of them it shows this:

View attachment 140031

Is there something different about the Cummins in the Rams that requires this phasing? I've asked our good techs about it and they all say they've never heard about phasing the pump.

It may be as simple as the noise aspect on a passenger vehicle.

 

[DanBarfknecht]

It may be as simple as the noise aspect on a passenger vehicle.

Thanks guys for the input,I will contact the mechanic.

 

[Ozymandias]

I've often wondered about this pump phasing. As you know, I'm certainly no CR expert, my experience is with the buses.

I've looked in our Cummins S/M's from '06 to '09's, and in all of them it shows this:

View attachment 140031

Is there something different about the Cummins in the Rams that requires this phasing? I've asked our good techs about it and they all say they've never heard about phasing the pump.

If it is in phase, the pressure within the rail stays more or less consistent during the injection event. If it isn't there is a small pressure drop. We know fluids are not compressible.

I imagine that the power rating of the engine has something to do with it to.
Small power output, smaller fuel input for each combustion event, less pressure drop.

 

[BigPapa]

May be. The '06 bus is rated at 215hp. What's the Ram, 325hp?

I can't see a Cummins S/M for the Ram engine to see if it says anything about phasing. Cummins may not have even offered one, just left it up to Chrysler.

 

[AH64ID]

This TSB talks about phasing it any time the pump is removed and reinstalled.

I recall a bunch of discussions back in the day about guys phasing them at home to eliminate an engine knock.

https://static.nhtsa.gov/odi/tsbs/2022/MC-10214624-9999.pdf

 

[Ozymandias]

May be. The '06 bus is rated at 215hp. What's the Ram, 325hp?

I can't see a Cummins S/M for the Ram engine to see if it says anything about phasing. Cummins may not have even offered one, just left it up to Chrysler.

305 was the weakest one, since then we climbed the ladder fast and steep.

 

[sag2]

Phasing the pump is strictly for noise. It would Have a minimal effect on fueling as it only eliminates gear rattle which can't possibly be more than a couple .001 of an inch play between gears.