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 Jeremy Your Own Question
Jeremy
Jeremy, Certified Truck/Bus Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 2791
Experience:  ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, EPA 608/609 HVAC Certified, Steering/Suspension and ABS/Brakes Technician
9290743
Type Your Medium and Heavy Trucks Question Here...
Jeremy is online now
A new question is answered every 9 seconds

I have a int 4300 dt466 it started missing under load.

Customer Question

i have a int 4300 dt466 it started missing under load. pulled all 6 injectors out and had them tested. all were fine! replaced can senor.
still missing . had a mech. hook a lap top up to it,said the fuel pressure sensor was bad ,replaced it ran fine for 1 hour,problems back. seems like if you stop the engine and restart it a few times you can get it to run fine for about 1 hour. I also replaced the pigtail going to the pressure sensor.
what should I try next?
Submitted: 4 months ago.
Category: Medium and Heavy Trucks
Expert:  Jeremy replied 4 months ago.

My name is ***** ***** I will assist you with your question today.

I'm an independent contractor and I don't get paid until a rating has been made.

We can go back and forth as needed to help resolve the issue you are having. Follow ups are free after ratings, so rate in confidence!

Was the harness for the injectors tested? Do you have oil coming out and around the plugs on the driver side of the engine going into the valve cover? If so, the harness is bad and needs to be replaced for there is oil in it and it is shorting out.

You wrote the fuel pressure sensor was bad. Was the Injection control sensor replaced or the Injection control Regulator? What was the pressure showing on the top of the engine?

_______________________________________________________________________________

You want a 5 star service and I want to provide a 5 star service. Please consider that I don't know your skill level as well as I can't see, touch, smell, hear the vehicle/machine in question. Please provide as much detail as possible and I will provide as much back.

Once an answer is provided, you should see a rating screen. Please rate my personal service to you. The ratings are my personal feedback, they are not the site feedback.

Thank you for allowing me to assist you through Just Answer!

Jeremy

Customer: replied 4 months ago.
THE INJECTOR WIRE KIT I DID REPLACE! THERE ARE NO PLUGS ON THIS ENGINE ,IT HAS INJECTORS! NOT SURE WHAT YOU ARE TALKING ABOUT THE PLUGS LEAKING OIL?
IT SEEMS TO START MISSING AT 1700 RPM. IF I SHIFT TO THE NEXT GEAR ,IT RUNS FINE TILL 1700 RPM THEN I SHIFT AGAIN AND ITS FINE TILL 1700 RPM AGAIN. CAN YOU THINK OF WHAT ELSE I SHOULD TRY. THANKS RICK
Expert:  Jeremy replied 4 months ago.

I know there are no plugs... You misread. The plugs, for the harness. You have the plugs for the injectors. Oil tends to get in them and cause grounding from the harness pushing oil from the injectors. If you replaced the harness, you can ignore that.

I would test the IDM on the truck and make sure the voltages are what they are supposed to be. Remove it and have International test it if you don;t have the software to monitor the pulse width. There is a high likelihood that one of the new injectors is acting up (if this is a new problem and if not...) or the IDM is acting up. You did all the other common spots and that leaves the IDM being tested.

Customer: replied 4 months ago.
What is the idm?
Customer: replied 4 months ago.
What about running the rpm up to where the engine miss, and pull the plug on each injector till i fine one that does not change the engine sound!
Expert:  Jeremy replied 4 months ago.

The IDM is the Injector Driver Module. It's job is to pulse the injectors for the fueling.

Unplugging each one at a time will code the engine and shut the engine down. The best way on these engines to test is to use the computer to do the injector buzz test, cut out test, and monitor the pulse width return from the injector.

Related Medium and Heavy Trucks Questions