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Andy
Andy, Technician
Category: Heavy Equipment
Satisfied Customers: 1571
Experience:  310s and 310t technician licenses, 17 yrs experience, International Diamond Certified Tech 7 yrs
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We have an 06 4300 International with a DT466 engine. We seem

Customer Question

We have an 06 4300 International with a DT466 engine. We seem to be getting air in the high pressure fuel rail. Seems like it's running with a miss and as the day goes on, the truck will shut off 2 to 3 times a day. Air has to be bled from high pressure system in order to restart truck.We checked the fuel pressure at filter housing. Maintains 65 plus PSI. Replaced filter, check valve, pressure regulator, transfer pump, metal fuel lines and seals and fuel suction lines from tank and orings. Also checked high pressure oil system, replaced all orings on injectors. Replaced turbo and actuator and both TPS switches. Codes that came up where VGT actuator and TPS switches. Where else can we check for air getting in high pressure system.
Submitted: 5 years ago.
Category: Heavy Equipment
Expert:  Andy replied 5 years ago.

Customer:

Hi there! My name is XXXXX XXXXX I think I can help you resolve your problem!

Customer:

Where are you bleeding air from the fuel system. Is it at the schrader valve at the front of the fuel manifold?

JACUSTOMER-ztagtedv- :

Yes. And the filter housing maintains full pressure.

JACUSTOMER-ztagtedv- :

We've have been having this problem for three weeks and just can't get our hand on the problem. We're are tired of throwing parts at this truck.

JACUSTOMER-ztagtedv- :

The truck use to be able to go out on the route and last for 6 hours. The truck went out yesterday and only lasted 2 hours.

Customer:

If you have no air in the fuel at the filter housing , but seem to be finding a lot of air in the fuel manifold , then your problem is likely going to be compression leaking by the injector bore and getting into the fuel manifold .

Customer:

compression then slowly builds up in the fuel rail to the point that you start developing what seems like a miss and then gets to the point that the engine dies . Then , you are force to hand prime and bleed air out of schrader valve on front of fuel manifold.

Customer:

If you are certain that there is no aerated fuel coming from the tanks and the filter housing , then the compression gasket on the ends of the injectors are leaking and compression may be coming into the fuel system. I just answered a question similar to this problem and it ended up being his injectors ( they were loose) . I would pull them all out , replace all o-rings and end gaskets , clean the injector bores and make sure there are no end gaskets stuck in the bottom of the bores. Then, if the injectors are fine and the tips are good, re-install them and torque to 30 ft/lbs. Reseal the high pressure oil rail again with new seal kit (have to replace rail seal kit every time you pull it off ) and re-install . Torque it to 23 ft/lbs starting with the center bolts and working your way out towards the end bolts.


 


 

Customer:

Hope this helps you ! Please don't forget to click on ACCEPT as this is how I get paid for my time and services here on JUST ANSWER ! I will stil be here for you if have any further

Customer:

questions about this job !

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Customer: replied 5 years ago.
We already replaced the orings and compression gaskets on injectors. We found five of the injectors to look good with no evidence of compression lost. However number 6 seem to have a dis coloration design in between bottom oring and compression gasket. Could this cup be cracked? And if so, how do we go about checking this? Thanks Devin
Expert:  Andy replied 5 years ago.

If in doubt , I would definitely have another look at it with a magnifying glass to be sure there are no hairline fractures anywhere on the tips of each injector and also further above towards the lower o-ring . Fractures are all too often overlooked and easily missed.

 

And remember, everytime you remove the high pressure oil rail to get to injectors, you MUST replace the oil rail seals again to prevent leakage . Those seals have to be able to hold up to 4000 psi of hydraulic pressure for proper actuation of injectors .

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