[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?

 

[BR1]

60 degrees does nothing to thicken the fuel. do you still have the in tank pump? any way to bypass the airdog? what is your RP at idle?

 

[Sean Steinberg]

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.

 

[Sean Steinberg]

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?

 

[BobSagetIsGod?]

Where’d you run the return from the cp3?


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[Sean Steinberg]

Back to the top of tank like the AirDog instructions said.

 

[BobSagetIsGod?]

What happens to fuel pressure if you unplug the FCA?


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[Sean Steinberg]

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.

 

[BobSagetIsGod?]

If it spike to 26k unplugged, and settles back down when when you plug it in, it should be good


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[Sean Steinberg]

So not the FCA you are saying?

 

[BobSagetIsGod?]

If the pressure spikes when you unplug the FCA, and settles back down when you plug the FCA back in, it should be functioning properly.


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[BobSagetIsGod?]

Airdog trouble shooting:

Loss of Fuel PSI/Running Out of Fuel

Initial question: Do you have flow from the PureFlow product?

If the answer is yes, where is the location of the gauge port being used?

The gauge port in the filter housing will not work when the fuel is routed around the stock fuel filter housing.

The gauge port utilized may not be in the pressure stream of fuel.

The pressure gauge is not reading pressure.

The vehicle is receiving fuel; however, the pressure relief for the pump (ex.: VP-44 / CP-3) is open and allowing fuel to return to the tank through this pump.

Pinch the line going to the pressure pump to stop the flow of fuel after the pressure gauge. Remove the relay from the unit's wiring harness. Place a jump wire between the red and yellow wires in the relay socket. Read the pressure in the dead head mode.
If the pressure goes up to the desired pre-set pressure, the problem is indicated to be with the pressure pump relief mechanism.
If the pressure does not show on the gauge, the problem is indicated at the unit or gauge. Check to another gauge.

Check the line connections. Engine to engine. Tank to tank.

Remove the Return to "Tank" fitting. Spring and ball in the pocket? Properly seated?

Remove the gerotor cap. Is the gerotor turning?
If the electric motor is running and the gerotor is stationary, pull the center gear off the motor shaft. Is the flat inside the gerotor center gear rounded or missing?
If the electric motor is running and the gerotor is turning slowly, check the voltage to the motor. Low voltage will reduce the motor RPM's; hence, reduce or stop pressurized flow.
If low voltage check the wiring connections and voltage regulator.


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[Sean Steinberg]

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?

 

[BobSagetIsGod?]

I would not, that’s just to find out if the FCA is working or not.


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[Sean Steinberg]

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.