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cumminsdr
cumminsdr, Mechanic
Category: Medium and Heavy Trucks
Satisfied Customers: 3544
Experience:  All types of Cummins applications
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I have a QSL 8.9L Cummins in a 135kw genset, a 559 low fuel

Customer Question

I have a QSL 8.9L Cummins in a 135kw genset, a 559 low fuel pressure fault that will not clear, well it clears but comes comes right back and I need to find out diagnosis of the problem as inj. are $900 apiece, I'm more of a Bosch or PT pump guy myself(old school)
I work for a school district in the Alaska bush and this is one of our newer models, 2008.
Can I get any help from you guys as I'm not necessarily stumped I need a little direction on pinpointing the issue.
Thanx,
JP
Submitted: 5 months ago.
Category: Medium and Heavy Trucks
Expert:  cumminsdr replied 5 months ago.

What is the engine serial number? Do you have the Cummins Insite program for troubleshooting ?

Customer: replied 5 months ago.
S/N 21788384 Have talked 2 Cummins n Anchorage, they told me 2 go online 2 Quickserve as I would have a certain # ***** free hits. Went to Quickserve but could not find a shop manual just install & service stuff????
Expert:  cumminsdr replied 5 months ago.

You still need the Cummins Insite program for testing the fuel system along with special test fitting and adapters. Causes of this fault include:

  • Excessive fuel inlet restriction
  • Fuel filter plugging
  • Air in the fuel system
  • Fuel gear pump output low
  • Fuel gear pump pressure regulator sticking or leaking
  • High-pressure pump capacity decay (high leakage to drain from the high-pressure pump)
  • Fuel rail pressure relief valve leaks to drain
  • Fuel rail pressure relief valve opens at too low a pressure
  • Injector fuel circuit leaks to drain
  • Pressure sensor reads more than 10 Mpa [1450 psi] lower than actual pressure.

The most common failures are the fuel pump High pressure relief valve leaking and leaking injectors. Fuel filters should be changed first. With out the Insite program it is a guessing game to what is really the cause.You may need Cummins to get out to your location for diagnosis and repair. Let me know if you need anything else, Please don't forget to rate my service.

Expert:  cumminsdr replied 5 months ago.

Hi. Just following up,Please don't forget to rate my service

Expert:  cumminsdr replied 5 months ago.

Hi, Just following up. Please don't forget to rate my service.

Expert:  cumminsdr replied 5 months ago.

Please don't forget to rate my service.

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