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Advanced Full Text Search - TIBU7417 - AFI Fuel Supply Line Rubbing{1274}

T echnical Information Bulletin

AF I F uel Supply Line Rubbing{1274}
Me dia Num be r -TI B U7417-00

Caterpillar: Confidential Y ellow

P ublicat ion D at e -02/ 01/ 2014

D at e Updat e d -02/ 01/ 2014

SB-10054882-7890

i05615949

AFI Fuel Supply Line Rubbing{1274}
SM CS - 1274
On Highway Truck:
CT660 (S/N: TGA1-UP; TGD1-UP; TEJ 1-UP; TRK1-UP; TKL1-UP; TEM 1-UP; TEP1-UP;
TGS1-UP; TJ S1-UP; TGT1-UP; TSW1-UP; TSY1-UP; TGZ1-UP)

Intr oduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is
known, use the solution that is identified below.

Pr oblem
If the fuel lines are not routed correctly, the AFI Fuel Supply line can rub through from the fuel system return line.
This situation can cause regen issues or an inability to perform regens. When the ECM senses a pressure issue in
the line, the ECM will stop sending fuel to the AFI from the DSI. You will not see a fuel leak in the area. What you
will see is a regen issue and aftertreatment temperatures not reaching the correct temp and eventually the ECM will
abort the OBFCT.

SYMPTOMS
Regen issues
Inability to perform regens
No fuel to the AFI from the DSI

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Illustration 1

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Example of an AFI Fuel Supply Line rubbing

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Illustration 2

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Example of an AFI Fuel Supply Line rubbing

Example of a Bad OBFCT with a Hole in the AFI Fuel Supply Line
Notice that the AFT Fuel Doser CTL actuated three times to purge the air. The AFT Fuel Doser CTL went to 0
and AFT Fuel Pressure 2 never climbed off 0 PSI. You will not see any leaks. There is no fuel being sent to
pressurize the line.
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Illustration 3

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Solution
Table 1
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Required Parts
Item

Qty

Part Number

Description

1

1

376-2674

Fuel Tube

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Illustration 4

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(1) 376-2674 Fuel Tube

Inspect and verify that the AFI Fuel Tube (1) is secured to the AFI bracket with the P-Clip. Ensure that the line
separator clip is installed on the return and AFI line. Be sure that the DSI supply line is not rubbing anything. Refer
to Illustration 4.

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Illustration 5

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Example of a good OBFCT after the AFI Fuel Supply Line was repaired

Notice the AFT Fuel Doser CTL actuated and stayed active and AFT Fuel Pressure 2 is working properly now.
Refer to Illustration 5.
C opyright 1993 - 2014 C ate rpillar Inc.
All R ights R e se rve d.
Private Ne twork For SIS Lice nse e s.

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