On my 2006 Cummins 6 speed truck is bone stock just straight piped it has a slight lope at idle no white smoke and when driving the truck blows a little bit of black smoke and in higher gears it seems to loose power . I’m thinking it’s the pressure relief valve or the fca but some insight would help. Truck isn’t making oil or losing mpg

Hook up a live data tool and watch the rail pressure. 

 

Also how many miles on the current injectors?

As far as I know 222000 the truck isles fine when it’s cold or when the ac is on but when it warms up it lopes 

Injectors are wasted... Time to replace them. Common rail injectors are only good for 100k to 150k most. Replace them all. Yup I know that a roughly $4,000 for just the injectors. Make sure to buy only new injectors if you want long life. 

 

Like on my 24V truck when the injectors wear out the idle starts to lope because the spray is wrong, and pop pressure are too low. Mine will lope as well on bad injectors. Even I find that 24V injectors are wore out about 100 to 150k also. Same problems can happen on CR engine too. The bad part is continue running on bad injectors could do damage to the engine. Last one I dealt with burned up cylinder 5 and 6. Lost all the compression and fuel washed the rings out. Needed to be sleeved. 

Edited July 30, 20205 yr by Mopar1973Man

Wouldn’t it smoke white and be making oil if it was injectors I have no cel 

No no change in smoke or anything you might detect a slightly long cranking time. Most injectors fail without warning without any smoke change. 

Truck starts right up every time 

Just like @Taz truck sitting in my yard he's got a couple of bad injectors. It starts and runs slightly off beat idle. No real smoke difference and no growing oil. He's parked he waiting to get the money together for injectors. The last truck that blew up was a 2005 Dodge and it washed the rings out but didn't grow any oil at all. Required rebuilding. Then the last truck I sold was a 2010 Ram 6.7L owner didn't want the injector replacement issue he also had the grid heater light on. The new owner has the issue which I notified them as well.

Idk I didn’t know if it was the pressure relief valve truck runs good in lower gear but higher gears it won’t get out of its own way 

Again hook up a live data tool and check your rail pressure. Then you might look up how to test return volume. 

 

Might even check the fuel pressure to the CP3. If it running weak it might be starving the CP3 on the top end.

Did I read that right @Mopar1973Man? $4000 for the new injectors on his CR engine?

Yes. That is roughly what new injectors cost. Remains are cheaper but like span might not be as good.

OMG! that's crazy. 

You know why I'm holding on to my 2nd Gen. 

 I feel lucky that I found the one I have. Not knocking the newer ones but wow, wouldn't have expected such a difference in price for injectors.

Even DAP is $500 per injector new times 6 that is $3,000.00. 

 I won't feel so bad when I order new ones for mine now