Fuel Pressure Fault code

[34nineteen]

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[njloco]

Wait, that's not a Bud he has in his other hand is it ?

[Cooter]

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OMFG, i'm pissing myself

[Ggeezer]

There is a U-shaped outlet hose from the pump that is internal in the tank. That hose likes to get pinholes and leak internally in the tank, it gets worse and worse until its not enough to feed the regulator and the pressure drops from the rock solid 49 psi its supposed to have until:

"the fuel pressure when the bike is running with ECM Droid and it hovers between 40 and 50 psi" which is PROOF there is something DEFINITELY wrong with the fuel supply. I know you don't want to do it again, but that failed test is PROOF there is something DEFINITELY wrong with the fuel supply.

IMO it's sure worth 45 mins to find out. Those hoses are very special and should come in a complete re-build kit. Take it out, stick the pump assembly in a bucket and jump it to a battery, plug the end, you'll know right away.

Hope that works for ya

edit: Whats you AFV? I'm betting it's nowhere near the neutral 100 it's supposed to be because it's been compensating for low fuel pressure.

Cooter,
If by "U shaped hose" you mean the corrugated translucent white flex hose that came with my rebuild kit then that was replaced at the time of rebuild about 2 years ago. I can easily pull the pump (since I'm such an expert now ) and test it as you suggest.

Questions,
When you say "put the pump in a bucket and run it off a battery" do you mean I should run it at least partially submerged in gasoline? I assume that I will need to find some way block off the pump outlet so that it will build up to at least 50 psi too, correct?

[Ggeezer]

Gord: Got your PM and email address and thanks. I'll respond this morning. On your pump situation:
The 2010 XB pump is unique to that year. Easily identified by the large metal "W" shaped clip holding the regulator to the housing...large black plastic motor shield...wiring harness unplugs from the pump body itself. The pump is unique to 2010 XB models and as you mentioned, fuel delivery system also unique to 2010. Pump is cycled on and off by the ECM receiving pressure readings from the fuel rail sensor. All prior XB pumps charge the system with key and kill switch on...then shut down till engine starts...then run continuously. Your pressure sensor is simply telling the ECM that the rail pressure is substantially below minimum, signaling the CEL...the stored fault code...the pump to run near continuously. You have either a faulty pump regulator or pump motor, or both.

You stated pump "replaced". With what???? If it was rebuilt by a novice with online Quantum parts, therein lies your problem.

Hey Barrett,

I replaced the original pump with one of your kits back in July 2020.

[34nineteen]

I will need to find some way block off the pump outlet so that it will build up to at least 50 psi too, correct?

The fuel pressure gauge will work as an effective way to block off the outlet and read pressure too. Use your existing fuel hose from the pump to the rail to connect the gauge/block off.


Back in 2021, Barrett was using pumps built by slave labor brought in from oppressed countries that he traded with the overlords for spices and Gros Michel ("big Mike") bananas. These pumps were assembled in the fiery depths of Lancaster county, where Barrett (formerly "user-deleted") ruled supreme with an iron fist. At this time, the "great uprising" and oppressed people struck back against the mighty Pennsylvanian and he was banished to the land of Mid-Atlantis where he now runs a motorcycle company. Granted, during this time pump quality was a bit off due to unrest with the workers. If he would have only kept that vending machine stocked, this could have all been prevented. Damn you!

[Cooter]

Cooter,
If by "U shaped hose" you mean the corrugated translucent white flex hose that came with my rebuild kit then that was replaced at the time of rebuild about 2 years ago. I can easily pull the pump (since I'm such an expert now ) and test it as you suggest.

Yes, but thats a good sign that it's new

Questions,
When you say "put the pump in a bucket and run it off a battery" do you mean I should run it at least partially submerged in gasoline? I assume that I will need to find some way block off the pump outlet so that it will build up to at least 50 psi too, correct?

Yes, but water is fine. Stick your thumb over the end and it will build pressure enough to check for leaks in the system. The cause of the 40-50 psi wandering is what we are looking for. A sp[lit regulator body, leaky connection or hose, etc, because if you were losing pressure somewhere else, it would be leaking on the floor.

I'm not sure it's true, but even if the 2010 fuel pump is a pulse-width modulated pump and the fuel pressure sensor controls it. It should still be a rock solid 49psi because theres no way to tune a fuel map correctly with inaccurately varying pressure.

[Ggeezer]

Thanks Cooter, I'm on it. I'll let you know once I run some of the fuel out of it first.

[Ggeezer]

Okay, I fixed it. It was the flex hose which was leaking at one of the hose clamps.

I tested it in a bucket of water with a piece of plastic tubing placed over the fuel pump outlet that had a very small hole in it to let some water pass. I hooked the pump up to a variable power supply that I have and ran the voltage up slowly to 12.5 volts. The leaks became very apparent very quickly so thanks Cooter for the tip. An added bonus is that I was also able to test the regulator at the same time which I can now confirm works perfectly.

I was able to use a short piece of .25 ID rubber fuel line instead but now there is interference between the pump and the inner part of the fuel tank/frame. I was able to squeeze it in there to test but I don't like that it had to be forced in there so I will probably order another flex hose from Barrett or someplace local if I can. At least I was able to get it to clear the fault code which makes me very happy.

Thanks again guys.

This forum is invaluable to a hack like me. Without it I probably would have junked this bike years ago.

Cheers, Gord

[Cooter]

Glad that worked out

Importantly, regular fuel hose is NOT rated to be submerged in fuel and will disintegrate quickly:/ Check that the hose you used is rated for that