How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Geoff Your Own Question
Geoff, Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 40
Experience:  Fleet Maintenance Training Instructor at Washington Metropolitan Area Transit Authority
Type Your Medium and Heavy Trucks Question Here...
Geoff is online now
A new question is answered every 9 seconds

I have a 2012 Peterbilt with an ISX cummins 600 hp - I was

Customer Question

I have a 2012 Peterbilt with an ISX cummins 600 hp - I was driving with cruise on and all of a sudden I got the nasty check engine msg, so trying to figure this out driving, let off the accelerator and the msg went away, applied acceleration and noticed that when boost pressure hit 30 pounds or more a lag in pickup occures then the check engine msg reappeared, so as long as i drive under the 30 boost manifold pressure i get no msg and able to work unit until a hill or when the need to accelerate quickly is needed like starting up at a lite or intersection etc. I have replaced the pressure temp sensor, mapping sensor, checked for leaks in air to air system, and the boots on the air to air, air filter is only 6 weeks old ( but also ran it with out air filter for a bit to see if that was an issue, while checking for air leaks in the air to air system found a crack in turbine housing on the turbo and have replaced it with a new turbo no change in the problem, as well replace the water seperator fuel filter, as well as the fuel filter.
I feel like it is starving for fuel at the higher need for fuel, could it a collapsing fuel line from the inside of the fuel line or the pump, or the crossover valve, or is there something else that i am missing.
I have not had it diagnosed on a computer yet because the code does not stay active.
your thoughts please
Submitted: 2 years ago.
Category: Medium and Heavy Trucks
Expert:  Geoff replied 2 years ago.

Hi, my name is ***** ***** I'd like to help you. It sounds like you've put a lot of parts on your truck. I can steer you towards the correct repair, but I need the codes that became active when these symptoms showed up. They should be accessible with the INSITE diagnostic software or most popular generic scanners, even though the faults are not currently active. You also mentioned that you replaced the turbo. What diagnostic software did you use to complete the installation? I only ask because it is necessary to use INSITE during installation of a turbo or there will be an active fault that appears.