Quote:
Originally Posted by barry123400
As soon as you notice the pressure starting to really drop off. It's probably time for a filter change. Besides all the side issues. When the fuel pressure drops down below .6 bar during normal cruising I think the fuel mileage is starting to decline.
Partially obstructed filters should have enhanced mileage as fuel to the engine was being restricted.. Until we get a lot of feedback we will not know how much fuel mileage is lost by very low pressure to the injection pump. There is no doubt it does hurt at this point.
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Correct:
When the fuel pressure drops, the first diagnostic step is checking/changing fuel filters.
Misleading/incomplete question:
Partially or fully obstructed filters do NOT enhance MPG, because the injection pump is starving = random weak uneven fuel delivery + suffering internal heating and lubrication loss (this does damage the injection pump).
Most drivers exacerbate the issue by heavier throttle application, driving until shutdown...
Note:
The injection pump fuel delivery piston and cylinder are cooled and lubricated by diesel fuel = drop the fuel pressure low enough/long enough (bad lift pump) or drive with plugged filters long enough = the injection pump will loose calibration and/or fail.
(as of April 2009)
Lift pump repair kits cost $10.00
Fuel pre filter cost $2.15
Fuel secondary filter cost $10.00
Average OM617 Injection Pump Rebuild cost $850.00
Have a great day.
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