Fuel Pump Timing Correction to Reduce Engine Noise

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Technical Service Bulletin
Technical Service Bulletin:
Released Date: 14-Aug-2019
TSB170124
Fuel Pump Timing Correction to Reduce Engine Noise

Fuel Pump Timing Correction to Reduce
Engine Noise
Warranty Statement
The information in this document has no effect on present warranty coverage or repair
practices, nor does it authorize TRP or Campaign actions.

Contents
Product Affected
•
•
•
•

ISX15 CM2250
ISX15 CM2350 X101
X15 CM2350 X114B
X15 CM2350 X116B

Issue
Symptom:
• Gear train impact noise that is most noticeable at or around 1500 rpm and worsens
as load increases.
• Gear train impact noise occurs at half-engine-order (once every 2 crankshaft
revolutions), similar to a fuel knock and has been described as sounding like a
“freight train” or “helicopter”.
Root Cause:
• Incorrect fuel pump timing. This problem is not related to the timing of the fuel pump
gear to the fuel pump. The fuel pump gear is keyed or indexed to the pump cam and
is always in a fixed position with respect to the internal timing of the fuel pump.
When the fuel pump is installed to the engine, it is possible to time the fuel pump
incorrectly with respect to the crankshaft position and thereby worsen engine noise.

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Fuel Pump Timing Correction to Reduce Engine Noise

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• Gear train impact noise caused by incorrect fuel pump timing will not lead to
progressive engine damage or mechanical malfunction
Verification
• Confirm gear train impact noise that sounds like a “freight train” or “helicopter”.
Reference audio clip below.
• Confirming that an engine noise complaint is caused by improper fuel pump timing
and not due to another issue is not possible without removing the fuel pump and
inspecting for its timing. No inspection or performance tests are available to confirm
fuel pump timing is the cause of an engine noise complaint prior to fuel pump
removal. See Resolution Section below.
• The following audio link is a representation of gear train impact noise producing a
“freight train” or “helicopter” noise.

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(http://tsb.cumminsvirtualcollege.com/TSB170124en.aspx)
Resolution
The following steps outline how to remove and install the fuel pump so the fuel pump is
timed correctly with the engine. Performing the steps below will help reduce engine
noise.
For X15 CM2350 X114B engines, perform the following steps:
• Verify base engine timing. See corresponding Service Manual. Reference Procedure
001-088 in Section 1.
• Remove high pressure fuel pump. See corresponding Service Manual. Reference
Procedure 005-116 in Section 5.
• Clean front face of fuel pump gear of excess oil.
• Locate fuel pump timing mark stamped on front face of fuel pump gear. Fuel pump
timing mark is either a “0” or “•” See Figure 1 below.

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Fuel Pump Timing Correction to Reduce Engine Noise

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Figure 1, Fuel Pump Timing Mark Examples.
• Using a paint marker, draw a line over fuel pump gear timing mark to outer edge of
fuel pump gear See Figure 2 below.

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Fuel Pump Timing Correction to Reduce Engine Noise

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Figure 2, Line over Fuel Pump Gear Timing Mark to Outer Edge of Fuel Pump Gear.
• Align a straight edge or ruler between center-line of fuel pump camshaft and center
of upper left fuel pump mounting hole. See Figure 3 below.

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Fuel Pump Timing Correction to Reduce Engine Noise

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Figure 3, Fuel Pump Camshaft Center Line and Mounting Hole Center Line Alignment.
• Mark fuel pump housing (ISX15 CM2350 X101 and X15 CM2350 X114B only):
◦ Count six complete fuel pump gear teeth clockwise from straight edge tool
and mark corresponding location on fuel pump housing.
◦ Example in Figure 4 below is an approximate location. All marks must be
made by counting gear teeth and not by matching Figure 4.

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Fuel Pump Timing Correction to Reduce Engine Noise

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Figure 4, Mark Fuel Pump Housing (ISX15 CM2350 X101 and X15 CM2350 X114B).
• Mark fuel pump housing (X15 CM2350 X116B only):
◦ Count eight complete fuel pump gear teeth clockwise from straight edge tool
and mark corresponding location on fuel pump housing. See Figure 5 below.
◦ Example below in Figure 5 is an approximate location. All marks must be
made by counting gear teeth and not by matching Figure 5.

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Fuel Pump Timing Correction to Reduce Engine Noise

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Figure 5, Mark Fuel Pump Housing (X15 CM2350 X116B).
• Rotate fuel pump gear until painted line over timing mark aligns with mark on fuel
pump housing. See Figure 6 below.

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Fuel Pump Timing Correction to Reduce Engine Noise

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Figure 6, Align Marks on Fuel Pump Gear and Fuel Pump Housing.
• Install fuel pump. See corresponding Service Manual. Reference Procedure 005-116
in Section 5. Never rotate pump while meshing fuel pump gear teeth with fuel pump
idler gear.
◦ While installing fuel pump, align fuel pump housing mounting holes to their
corresponding bolt holes in gear housing while fuel pump gear is inserted into
gear housing.
◦ If fuel pump gear will not mesh during insertion into gear housing, do not
rotate fuel pump more than ½ a tooth spacing to achieve mesh. Rotate fuel
pump away from engine if possible.
For X15 CM2350 X116B, ISX15 CM2350 X101, and ISX15 CM2250 engines, perform
the same steps as above in addition to the following step:
• Check the gear lash. See corresponding Service Manual. Reference Procedure 001088 in Section 1.
Production Status
Implemented for production. See Table 1 below.
Table 1, Production Information
ESN First

Build Date1

Plant

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Table 1, Production Information
ESN First

Build Date1

Plant

80021663

3 November 2017

Jamestown Engine Plant

Engine build date can be found on engine dataplate.

1

Document History
Date

Details

2017-11-28

Module Created

2019-8-13

Added noise audio clip. Divided directions by specific engine
model.

Last Modified: 14-Aug-2019

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