Andair Fuel Pump Problem

[Flyguytki]

Hmmm. thats no bueno. The only thing i could think of is what Andair said about putting a little oil in there, its completely off the wall and I know you are already doing it but its worth asking, Are you sure your supplying 12 volts to it? That could have a affect. maybe.

-david

[TS Flightlines]

Hum-----
This is an interesting thread. My Friend Dennis has a AFP in his RV8, and we did a first engine run last weekend. AFP pump primed immediately. So, I'm not certain of the priming issue with the Andair pump.
Tom

[CharlieWaffles]

Tom, it's not a priming issue, but a known issue (at least at Andair). Back in 2011 and older, they tested all pumps and packaged them up. They did not flush out the fuel and have seen a number of these pumps seize after they sat for a long time. It doesn't affect the pump if put into use soon after purchase. They are now shipping all units with preservative oil to combat this situation. But mine was just old enough from my build to be part of the old process.

[CharlieWaffles]

Originally Posted by Flyguytki

Are you sure your supplying 12 volts to it? That could have a affect. maybe.

-david

Yup - metered and also VPX confirmed amp draw.

[Wayne Gillispie]

Originally Posted by TS Flightlines

Hum-----
This is an interesting thread. My Friend Dennis has a AFP in his RV8, and we did a first engine run last weekend. AFP pump primed immediately. So, I'm not certain of the priming issue with the Andair pump.
Tom

Same here with AFP. No issues with tractor valve either.

[CharlieWaffles]

So here's the latest issue with the pump. It's not seized up, but now I need to figure out what's causing the problem.

I have the pump connected to the J12-12 pin on a VPX sport and have it set to 6Amps. When I power up the pump it still makes the weird pitch noise for a few seconds and then shuts off. I removed the pump today and connected it to my bench power supply (also 12V) and the pump worked! I reinstalled the pump and it went back to making the same noise. I connected the bench power to the pump while it was installed in the plane and it worked. So it has to do with the power in the plane. I used the multimeter and verified that when the assigned switch is triggered, the voltage on the line goes to 12V. I checked the ground from the pump and even used a different ground point ? no go. All the wiring is 18Awg, the +Vdc is about 10 feet long. The only thing I didn?t do yet is yank the pin out of the J12 plug and connect my bench power supply to it. When the pump is turned on, the VPX (via AFS EFIS Screen) draws up to about 2A briefly before the pump shuts itself off. Occasionally the VPX will show a fault and requires a reset when this occurs ? but not often.

I am wondering if my +vDC line is perhaps too small of gauge?
The crimp connector for the J12 pin is bad
J12-12 is bad and I should try a different pin to see what happens
Increase the amperage for the pump assuming it has a momentarily higher initial need. Spec sheet just shows 6A max (http://andair.co.uk/pdfs/PX375-TC.pdf)

[Wayne Gillispie]

I used 16 ga to mine. You may be reading 12V open circuit voltage when checked but when motor is in the circuit your voltage drops too low. Check voltage after pump is energized.

[N427EF]

All the wiring is 18Awg, the +Vdc is about 10 feet long.

I am wondering if my +vDC line is perhaps too small of gauge?

It may be and why is it 10 feet long?
Just hook up a jump lead to your main bus and see if the pump runs, don't see why it wouldn't after it's been running on your bench.
you'll confirm that you may actually have a VPX problem not an Andair pump problem.
FWIW, my pump wiring is 16G and less than 5 feet long protected with a 5 amp SCB.
It sounds like you are closing in on the problem hope you get to the bottom of it.

[CharlieWaffles]

The 10' is a rough estimate of wiring from the copilot side off of the VPX along the panel, the side fuselage under the pilot seat and then up the tunnel to the pump. It is likely to be under that length, but wanted to over estimate just in case.

[grayforge]

Any further results from troubleshooting this issue?