another 6NZ fuel preasure ??

loads4fun · Dec 11, 2018

truck 307 said: ↑

One day " my" unresolved problem will also be behind me.
CAT said zero blow by on injector seats and O rings when they ( under my platinum warranty) swapped out all 6 injectors trying to resolve my issue.
Bottom gears from a stand still , all the clean smooth power I want. After the truck sits a few days, the same, smoooth running.
After 10+ hours truckin, the same, all good.
But the 90% of the time over and above that, shake, sputter, pop.
If I'm off the throttle for 5+ seconds,
( coasting down a grade, rounding a curve to get on a big road, etc)
I can put foot to floor through all 18 gears and no issues.
Any time I'm off the throttle 5+ seconds all is Good thereafter for usually the next 5 to 15 seconds of regular throttling .
But otherwise, I'd swear I was running out of fuel or timing is being thrown out.
Coolant temps climb, fan comes on and no way can I get RPM's above 1500 as it feels like I'm gonna rip the crank out with the vibrations and low power.
Tank vents all good. Fuel supply lines new. Pump is a year old. TPS also a year old. Both wiring harness replaced.
All sensors replaced. Dropped tanks to check suction tubes all good. Zero air in Fuel, both pre and post head ( CAT hooked up sight glasses we drive for 90 minutes)
Zero blockage in exhaust. Fuel pressure great. Always use CAT filters.
Fuel pressure regulator valve changed 3x. Divider and divertor valves changed.
ECM swapped out 2x.
It's driving me insane.
Open to ideas if you've got one.
Thanks guys .
P.S...the throttle positioning sensor was never calibrated was told not needed . But I called around and the consensus is that if the sensor and pedal ( complete) is changed then no, no need to calibrate. But if the sensor "only" is changed then yes, it should be calibrated but the guy's at CAT say it won't make a huge difference ...hmmm. Gonna get it done anyway, gotta get to the bottom of this.

check the cam gear, I've seen them crack and break where the weights are, it will chip out by the tone teeth.
"HELP"......
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another 6NZ fuel preasure ??

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another 6NZ fuel preasure ??

loads4fun Bobtail Member