Paccar no pulling power

Could there be a more true statement in our line of work!!

 

I honestly hate it when I hook up and see faults that I have seen the failure for a thousand times over, and you are certain what the likely cause is. The moment you cut corners and don’t follow procedures it will surely bite you in the ### and make you look like a fool for assuming it was the same as all the others.


If it was easy as getting the code and changing said part, we would not have to train 100 hours a year and charge 200 bucks an hour.

 

Ok so I cleaned and checked all the air management sensors. Still nothing. I actually had a check engine light on last week and it was the fuel shut off valve for the diesel doc injector. When that light was on, the truck actually had more power. I have since fixed the problem and the light is out, and now back to the low power issue on the top end as usual. I had a friend explain to me that because that was considered to be an EGR fault, it will close the EGR to protect the engine and that is why I had more power because I was able to build more boost. So now it has me wondering if it is something to do with the EGR? I did a road test while monitoring the sensors and the EGR position. The only difference I could find on the EGR was when I did a key cycle where I have good boost for a minute or two, the EGR position read 41-42, and when it didn't have the proper boost, it went down to 34-35. Do you know what that number represents? Percent open? Percent closed? Any other ideas regarding the low power issue on the top end? I am getting to the end of my patience trying to figure this problem out.

 

Ok still working on this low power issue. When the engine is in Standard mode is when it has low power. When it goes into SCR High Efficiency mode, it seems to run better. Also runs good when in SCR Heating mode when from cold. Also notice as soon as it goes from SCR Heating to Standard mode, the BPV goes to 100% open and stays at 90 to 100 the whole time. When it does go into SCR High Efficiency mode, it will drop and start fluctuating. I don't know if this is how its supposed to work. Its just an observation. This testing was done while bobtailing. Also a reminder that I have put 6 NEW injectors already in this truck. New differential pressure sensor, new pressure before turbine sensor and pipe, and new boost sensor. I have also taken off and cleaned the other pipes associated with these sensors. It also has new Nox sensors before and after catalyst, new def doser, and a new EAS computer. There are no check engine lights on and no codes in the computer. I have also cleaned the EGR Venturi, the pipe from the venturi going across the front of the engine to the intake horn, and the intake horn itself. I have also taken off, cleaned and checked the temp sensors with a meter where possible. Also the humidity sensor. I also left them out and ran a recording on these sensors and cooled them down with ice and they all seemed to respond correctly. Any ideas or what to do next?

 

Any information from anyone?

 

Standard mode

 

Solved?

 

No not yet. Still working on it.

 

Have you solved yet have been having a similar problem

 

UPDATE!?!?

I'm having the same issue. Mx13 deleted. Low power and chugging after high power demand. (e. uphill pull) Resumes to normal after letting off gas for some time, until next high power demand.

Makes me think it's starved for fuel. Seems like it uses up what pressure there is then starts limping.

My first try will be to change the Lift Pump. The high-pressure pumps could be starved for fuel if that is weak.

Got a SPN 1347 and SPN 5571 code briefly. Both refer to fuel supply.