Cat Lift Trucks (& Caterpillar) P5000:
intermittent engine surge at full throttle

For discussion: I have an intermittent engine surge/hunt at wide open throttle. Things checks are fuel pressure, MAF sensor, wiggle test on wire harnesses, carb clean sprayed around joints and vacuum hoses, no change during surge/hunting. Truck is not producing a fault code. A/F LP goes out of range, normal is 75-125, sometimes runs 130-135. Anyone with experiencing this problem?
  • Posted 20 Nov 2014 11:11
  • Discussion started by dieseltech
  • Michigan, United States
Showing items 16 - 17 of 17 results.
my money would be the assistant injector, and would swap one from a known good unit for testing, but what they said above is right on.
  • Posted 20 Nov 2014 13:12
  • Reply by edward_t
  • South Carolina, United States
"it's not rocket surgery"
Does this truck have a longer than normal crank time when its first started???
If the A/F ratio is going high,possible causes are intake air temp sensor......MAF sensor...is it dirty??? Can you check O2 sensor and see if it is switching back and forth??
Another possibility is the assistant injector leaking or not working properly as well as main injector issue....or a pressure relief valve in the injector holder is sticking open some.....with the engine off and key on do you hear fuel going thru injector and intake and going past relief valve......there are two relief valves in the injector holder...might be good idea to remove injector holder remove main and assistant injectors and clean the injector holder of gum and tar...also check fuel PSI...should run around 4.5-5 PSI
  • Posted 20 Nov 2014 11:24
  • Reply by kevin_t
  • Pennsylvania, United States

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