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The machine I'm working on only starts with starting fluid.

Customer Question
The machine I'm working...

The machine I'm working on only starts with starting fluid

Mechanic's Assistant: What is the complete model and serial number of your machine?

The model is a CP56 serial number is *****

Mechanic's Assistant: Are you fixing this yourself? What have you tried so far?

Yes. I've replaced both diesel filters and check for fuel pressure. I ran Cat Et and I get ah low fuel pressure code

Mechanic's Assistant: Sometimes things that you think will be really complicated end up being easy to fix. The Heavy Equipment Mechanic I'm going to connect you with knows all the tricks and shortcuts.

Ok thank you sir

Mechanic's Assistant: Anything else you want the equipment mechanic to know before I connect you?

No that's it sir

Submitted: 3 years ago.Category: Construction and Road Equipment
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Answered in 9 hours by:
11/16/2018
Mechanic: catmastertech, Technician replied 3 years ago
catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 3,994
Experience: Field service technician for CAT 19 years.
Verified

Hello,

I am sorry no one could help you earlier. I hope this is not too late to be helpful. All experts are not employees, we work from home in our spare time to answer questions and like most places, this is a busy time for everyone.

I am assuming this is the code you found. See the details below.

E398 Low Fuel Rail Pressure

SMCS - 1702-038

Event E398

Conditions Which Generate This Code:

The Electronic Control Module (ECM) detects a fault with low fuel rail pressure. The ECM detects the following faults:

  • The ECM determines that the expected fuel rail pressure is lower than the pressure that is requested by the electronic control system.

     

  • Diagnostic code 0262-03 5 Volt Sensor DC Power Supply voltage above normal is not active.

     

  • Diagnostic code 0262-04 5 Volt Sensor DC Power Supply voltage below normal is not active.

     

  • Diagnostic code 1797-03 Fuel Rail Pressure Sensor voltage above normal is not active.

     

  • Diagnostic code 1797-04 Fuel Rail Pressure Sensor voltage below normal is not active.

     

  • No diagnostic codes are active for the fuel rail pump.

     

  • No diagnostic codes are active for the fuel injectors.

System Response:

The event code will be logged.

Possible Performance Effect:

E398-2

The engine will be derated until the keyswitch is turned to OFF.

Troubleshooting:

Test Step 1.

Low fuel pressure may be caused by the following faults. There can be a fault with the fuel return system. There can be a fault with the fuel pressure control. There can be a leak in the high pressure fuel system.

A failed relief valve, the fuel pump or an electronic unit injector may cause an event code to be logged.

The event code does not represent a fault with the electronic system. This event indicates low fuel rail pressure. Refer to Testing and Adjusting, "Fuel System - Inspect".

Results:

  • OK - STOP

I have seen a few pressure sensors cause this and a few relief valves. However, I often find a leakoff issue with the pump or injectors.

You will need to perform the leakoff test with the CAT tooling to find the source of the leak.

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catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 3,994
3,994 Satisfied Customers
Experience: Field service technician for CAT 19 years.

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