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2017 5500, 80k miles fuel rail pressure issue truck is surging and won't run

1459 Views 14 Replies 3 Participants Last post by  Sean Steinberg
2017 5500, 80k miles.

Fully deleted the truck, head studs, valve springs, AirDog 4g2 last week.

First week out truck was doing great.

Then as it got colder, rail pressure was dropping.

Figured this was due to colder temps, but at 60-70* was a total dog and would barley move. Once tank was below 1/4 and fuel was warm ran fine.

Already have a BD Diesel fuel heater on order. But don't think those temps would thicken the fuel that much???

Put a fuel rail plug on also.

That was about a 3000 mile trip.

Now 300 miles on the next haul, truck wont run. Day started off fine, but have had a surging get worse and worse where now I can't do 30mph.

Idles fine, rail commanded pressure vs rail pressure pretty close on display.

No smoke colors from tail pipe.

Trying to move rail pressure is under 3k sometimes. But in park can get to 13k+.

Checked all the fuel fittings and wires.

Currently down trying to find a shop to work on it.

Any ideas?
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Tank pump is gone. I pulled the AirDog fuel line off the CP3 and fuel comes out quick.

When I pull the banjo bolt next to the relief fuel plug, fuel comes out at idle.

So we are leaning to a bad injector o-ring. I didn't change the o-ring when I pulled the injectors for the valves.

Have no o-ring kit arriving Sunday, and Monday installing new o-rings to see if that does it.

Between the new o-rings, and taking all the feed tubes off and on, hopefully we find it.
Did the injector & feed tube o-rings, and copper washers.

Did a few miles in town, then on the highway for 5 miles, everything was good.

Came back cleaned up tool, and headed north.

Ten miles later issue is back.

Surging fuel pressure to where you can't drive the truck. Stalled out at stop lights.

Could this be the FCA? Looking online some people say to test remove and shake for a ball sound. Any other tests?
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Back to the top of tank like the AirDog instructions said.
Just did that and started the engine.

Goes to 26k, won't change. Throws codes.

Was temped to unplug and go for a drive, but I'm at a truck stop and there is not much parking around here.

Will try that in am on way to auto parts store if no bette ideas.
So not the FCA you are saying?
I don't have a pressure gauge on my Air Dog.

Throttle control message light came on when I unplugged the FCA.

When the FCA fails, does it fail open, closed, or does it fluctuate back and forth?

If I unplug the FCA, can I drive the truck without hurting anything?
Installed a new FCA, no cure.

Just about gave up. Was calling shops to drop the truck off to.

Shop asked about the filters. I said I thought to try that, but just put this new Air Dog system on, filters had less then 2,000 miles before the issue started. And this truck burns a lot of fuel, so highly unlikely I got bad fuel. I also emptied the filters out a few times, no gunk or water came out.

Sure enough, changed the filters, issue is totally solved.

Boy do I feel dumb!

I also have a fuel pressure gauge to mount to the Air Dog on order.
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