Fuel Pressure Fluctuation

[Rawze]

(05-31-2020 )B model Wrote:  ... My mechanic assured me that you never needed to set overhead unless the cam or injector went bad.
...

FIRE YOUR MECHANIC!!! - NOT ADJUSTING THE OVERHEAD VALVES OFTEN LEADS DIRECTLY TO A WIPED OUT CAM!!!

Cummins says 500k maximum, but realisticly, it should be done every 250k miles (or equivalent hours) if you value the life of your cams and engine.


* The injectors leaking. They get leaky if no one adjusts the overhead valves and injeoctr rockers often enough. - Always do an overhead adjustment Both valves and injectors before doing an injector leak test using the test block. This is because the injector rockers back off (get loose from wear) over time and the needles do not seat 100% closed, giving a false reading as a leaky injector if they are out of adjustment.

* The exact opposite happens on the valve cam side rockers. They get tighter over time due to valve seat wear and the rockers start riding the cvam all the time and wipe it out. - 250k adjustment intervals are your friend towards preventing wiped cams.

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Fluctuating idle will be usually one or more of ...

* Leaky injectors.

* Air in fuel system.

* Worn our metering (fuelling) actuators where they have developed slight step-wear in the shanks of the plungers (very common). ref: http://rawze.com/forums/showthread.php?t...619#pid619

* worn out head, leaky valve seats and guides.

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Wiped out cams...

* NOT adjusting your overhead valves often enough.
* Not changing oil often enough (oil changes should be based on fuel mileage, not any set interval). - related info: http://rawze.com/forums/showthread.php?t...4#pid48014

* Not keeping after your EGR and other systems (regular EGR tune-up, etc.) , the result of which is excess soot in the oil all the time.