desired rail only 12K ?

DPC

DPC

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Sep 10, 2009
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I have a 2006 5.9 cummins, FASS lift pump, and EFI. I just changed crossover tubes (6.7 style) coper washers, o-rings, and ARP studs for injector hold downs because I had a leaking tube. After I got everything done the truck starts but acts like it is in limp mode. No smoke, no rough idle, no codes, just no power. After logging with EFI my desired and actual will only reach 12K even at 100% throttle. I can unplug my CP3 and PSI will hold at 24-25K but my desired will only go to 12K and still no power?

I changed all fuel filters just to rule that out, no change. I am not making oil either.

I also reflashed ECM with stock tune, no change.

When I drive it I can floor it and it will maybe reach 25mph, rpms will even climb to 2000-2200 or so but it just does not want to go.

Suggestions? Thanks.
 
Yea take them hold down studs out and use the factory bolts.I had those studs,not worth 5 bucks of you ask me.

I know a few people have had problems with the new style crossover tubes.More then likely a tube is not seated in the injector right.
 
If the crossovers were leaking when I unplug the CP3 it should not be able to max out rail pressure? Also why is commanded rail only 12K when at 100% throttle?

I just finished going through the entire fuel system again. I had extra washers so I put new ones back in. When I took it apart everything was tight and torqued to spec like it should be. I matched the crossovers with the injectors when I reassembled. I have the same issue no power. Truck does not smoke or idle rough, starts like it should.
When I drive it I can floor it and it will slowly build up power and start moving, it will even shift. At one point it seemed to get moving then I heard a squealing type sound (torque converter slip?) . Trans oil looks good and trans temp was only 110.
 
Update. Went on another test drive and slight improvement. Pedal acts dead for about 5-6 seconds slowly building speed then bam it will hit and take off. It won't pull on top like it should but much better than it was. I could almost drive it if it werent for the dead pedal on take off. The pedal goes back to being dead every time you let off the throttle even when going 65mph. It seems to pull out of the dead pedal slightly faster if i feather the throttle. Is the TPS going bad? I still have zero codes.
 
logged run

RPD and RPA are always very close. Can rail PSI still be maintained with a leaking crossover? I really don't want to pull the tubes again. How can I upload the EFI log file? I get an "invalid file" message when I try to upload. Thanks.
 
Are running the duals? if so it sounds like 1 of the FCAs is dead or electronic problem with the splitter (Module)
 
No clue.

I put everything back to the way it was, old feed tubes and hold down bolts. No change. I have no clue as to what is wrong. I still have a dead pedal.
 
It may be the pedal or a bad FCA I would change out the FCA First The TPS should throw a code!
 
If your desired rail is 12k...it has nothing to do with a potential leak.

Desired is set by the tune in the ECM. Your tune is dictating your desired.

If you meant to say, actual, then yes you have a leak.
 
2007 5.9 said:
If your desired rail is 12k...it has nothing to do with a potential leak.

Desired is set by the tune in the ECM. Your tune is dictating your desired.

If you meant to say, actual, then yes you have a leak.
Click to expand...

Desired and actual are the same or very close. This certainly is not a leak but an electronic gremlin. I went against my better judgment and changed everything back to stock because of the coincident of the fault. I will check the TPS and FCA tomorrow.
 
If desired/actual are same and it's commanding 12k...look at TP and calc load.

If the ECM doesn't see demand for fuel, it screws everything up.
 
Leave it at stock until you can pin-point the source of the problem. Check your throttle position VS load compare.
 
TCDiesel said:
Leave it at stock until you can pin-point the source of the problem. Check your throttle position VS load compare.
Click to expand...

Yes it will stay stock until the problem is identified. At 100% throttle 12K was the highest it would command. Truck will hardly move.
 
Check and see if you have a MAP sensor acting up. I had a dead pedal issue recently with no codes and it wound up being a bad MAP sensor. Log it and see what its giving you. Mines an 05 so I didn't have the luxery of EFI to help identify the problem
 
2007 5.9 said:
What's throttle position?
Click to expand...

It reads 100% with the pedal to the foor. TP position and percent seem to match as I moved the pedal. I will check it again when I get home from work.
 
Who's doing your tuning?

Would you be willing to try a tune to see if it's tuning or other?
 
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