Loss of Fuel Prime Causing Hard Start Issues in Certain 3456, C15, and C18 Generator Set Engines{1258, 1261, 1262} Caterpillar

Loss of Fuel Prime Causing Hard Start Issues in Certain 3456, C15, and C18 Generator Set Engines{1258, 1261, 1262} [TIBU7348]
Loss of Fuel Prime Causing Hard Start Issues in Certain 3456, C15, and C18 Generator Set Engines{1258, 1261, 1262}
1.1. Introduction
2.1. Problem
3.1. Solution
C18 (S/N: ZKB1-UP)
Generator Set:
3456 GEN SET (S/N: CCB1-UP; C1G1-UP; C3G1-UP; C4G1-UP; CAH1-UP; GHJ1-UP; C2T1-UP; CBX1-UP)
C15 GEN SET (S/N: T4A1-UP; ZKA1-UP; PEC1-UP; C5E1-UP; STG1-UP; C5H1-UP; C5L1-UP; NKL1-UP; X5M1-UP; X4R1-UP; CYY1-UP)
Petroleum Engine:


The problem that is identified below does not have a fully validated solution. Until a permanent solution is validated, the solution that is identified below has in some instances, improved performance.


On occasion, some 3456, C15, and C18 engines have been experiencing hard start issues because of loss of fuel prime. This issue has been observed occurring mainly in units that were exercised at intervals of more than one week.


If the 233-6742 Check Valve Gp is installed in the secondary fuel filter base, replace with the 327-4448 Check Valve Gp .

An orifice in the new 327-4448 Check Valve Gp provides the benefit of fuel flow for priming. This orifice allows for priming without having to overcome the high cracking pressure of the 233-6742 Check Valve Gp . Additionally, this orifice regulator and check valve provides an air purge mechanism, thus improving priming and starting capability. The additional step of incorporating the 447-1817 Check Valve and 443-6656 Check Valve is needed to prevent loss of fuel prime.

Perform the following procedure for the installation of the check valves. Table 1 contains the part numbers needed for this change. Some parts listed in Table 1 may not be needed if the parts were previously installed.

Note: Ensure that health and safety requirements are adhered to at all times.

Table 1
Item     Qty     Part Number     Part Description    
1     1     6K-9194     Flared Elbow    
2     1     214-7568     O-Ring Seal    
3     1     447-1817     Check Valve    
4     1     327-4448     Check Valve Gp    
5     1     443-6656     Check Valve    
6     1     137-5541     Fuel Priming Pump Gp    
7     1     195-1068     Fuel Filter Base As    
8     1     326-1641     Water Separator and Fuel Filter As    
9     1     343-5527     Bowl    
10     1     6V-3683     O-Ring Seal    

  1. Lock Out and Tag Out generator is applicable. Use the following procedure to isolate the generator set before starting any work on the unit.

    1. Open the generator set breaker.

    1. Put the 4-position start switch "ESC" into the OFF position on "EMCP2" or push the "Stop" button on the "EMCP3".

    1. Activate the emergency stop.

    1. Isolate the AC auxiliary voltage for battery chargers, coolant heaters, generator space heaters, and disconnect the battery cable.

    Illustration 1g03506445

  1. Remove the 233-6742 Check Valve Gp and replace with check valve group (4). Torque the check valve to 28 ± 3 N·m (21 ± 2 lb ft).

  1. Install check valve (3) at the fuel return port of the secondary fuel filter. Install o-ring seal (2) on the male end of check valve (3). Refer to Illustration 1 for location.

  1. Remove any previous check valve installed at the tank supply.

    Illustration 2g03506476

  1. Install check valve (5) after the primary fuel filter, refer to Illustration 2. Torque check valve (5) to 58 ± 5 N·m (43 ± 4 lb ft).

    Note: Since the check valve will be installed in the field, the risk of contamination will exist. Contamination can affect proper operation of the check valve.

  1. Verify that the check valves are operating properly after installation.

    1. Start up and run the engine for a minute.

    1. Shut down the engine.

    1. Disconnect the line between the primary fuel filter and the fuel transfer pump. Use the fitting between the fuel transfer pump and fuel inlet line for the disconnection.

    1. Let the line sit for 15 minutes or more.

    1. Verify that the vertical fuel line is still fully primed by looking down at the line.

    1. Verify proper operation. Ensure that there are no fuel leaks. Verify that no additional check valves are installed other than the check valves that are listed in this article.

  1. Verify that the primary fuel filter system includes the following components:

    • 195-1068 Fuel Filter Base As

    • 326-1641 Water Separator and Fuel Filter As

    • 343-5527 Bowl

    • 6V-3683 O-Ring Seal

    Note: Verify that the latest improvements for the fuel system have been implemented. Refer to Engine News, SEBD9581, "Hard Starting of 3456 and C15 Generator Sets" for more information.

  1. Inspect the 137-5541 Fuel Priming Pump Gp . If necessary, replace the priming pump and the 1P-0436 Gasket . Leakage of the hand priming pump can contribute to drain down and hard starting. Inspect the three letter code on the base of the pump. Install pump with the letter "T" or above. The letter "T"indications that the pump was manufactured in 2012. The gasket is green in color.