Truck Data - 06 / 2WD / No Mods / 230k / all stock / No codes

On my last trip with the 5th wheel before I sold it a year ago, the truck just seemed like it was struggling while merging into traffic from a feeder with a slight incline. I sold the 5th wheel and havent had any issues other than a noticeable loss of power. I didnt worry about it much since I wasnt pulling anything, no codes, decent MPG and starts every time.

Fast forward a year and I just bought an all aluminum and fairly heavy boat and the loss of power is becoming an issue.

Ive got a gauge pillar - temp are fine, 5-600 cruising unloaded, 6-800 loaded and 1000-1100 if Im on it on an incline but there isnt any power, boosts up to 22-26 without issue but I do get black smoke until she spools up.

Ive got an ELM and Torque app so plugged it in to watch rail pressures and notice that Im not getting over 19500 ... ever. Idle is from 6-7k and very erratic, but really stands out is that the pressure gradually increases with engine speed and drops everytime it shifts around 3-5kPSI leading me to believe the lift pump is shot and Ive been running on the LP boost pump pulling from the tank. At 70 if I put my foot in it, it drops to 14-15k and will slowly work its way back to 18-19 ... never 20-23

Im not trouble shooting a 230k mile lift pump, a new one will be here Saturday but the erratic idle has me worried about the FCA. Ive been trolling these forums for a while just to familiarize myself with diesels / cummins issues over the years but this one I need a little help with.

Ive had it since new, regular maintenance like clock work and plan on keeping it until it wont drive anymore ...

 

I need to add something I saw as well when doing some investigations.

I noticed that the boost pressure being read on the ECM is off at certain times up to 5-7 psi compared to my mechanical gauge so I ordered a new MAP sensor. 230k miles and it may be starting to **** the bed.

Could I be defueling because the engine thinks its getting more boost than it actually is and falling on its face ?

Might also explain why I dont hear the turbo anymore like I used too, but Ive checked it, the wheels free and no lateral movement.

 

Replacing the lift pump may help, have you been running a clean fuel filter with the same issue? The FCA is relatively easy to replace and only $100 at your local Cummins dealer. I replaced mine a while back, dodge wanted about $300 if I recall correctly and the cummins dealer had one in stock for $100.

Install/removal is 3 torx screws- they are a PITA since you need to be careful not to strip them out

The erratic idle sounds like a dirty filter or FCA more so than lift pump.

The lack of rail rail pressure when pushing it sounds like a Lift Pump, FCA, or Rail pressure sensor. It could be a bad CP3 also but I wouldn't worry about that at this point. It also is likely not the RP sensor since these are usually reliable.

I know you ordered a lift pump already, depending on what you are looking to do with the truck I highly recommend upgrading to a Fass w. Sump kit or air dog. I have been very happy with mine. Great RP, smoother idle, water separator, and filters need to be changed every 25k miles or once a year in my case.

 

The fuel filter gets changed every 10k with oil changes and made no difference. Engine idle speeds pretty stable its the idle pressure thats swinging 1000 psi.

Only problem Ive had with this truck is I lost the #4 (if i recall) injector feed line and dumped 1/4 a tank into the engine compartment in the 30 seconds it took form e to realize what was going on at 75mph several years ago.

 

I think we have all had issues with that #4 line so you're in good company. I would stick with your plan of lift pump and see if there's an improvement. We have about same mileage- I put my fass on at 215k when I didn't have a RP gauge yet so I am not sure how my stock pump was holding up at that point

 

Thx for the help, Im keeping this baby stock and reliable. She's been the best vehicle Ive had by far and just needs a little TLC at the moment.

I seriously considered the FASS system but couldnt digest 400+ bucks for it when my truck ran perfect for me with the standard lift pump.

Ive got a Jeep I built up as a play toy

 

Replaced the left pump, it was nasty and helped improve things a bit.

Rail pressure reacts faster but Im still having a reduction in pressure everytime the trans shift and still cant get over 19.5k PSI

Im going to get an FCA from Cummins tomorrow and rig up a pressure tester and check for boost leaks.