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Diamond_Dan wrote:Our fuel pump breaker popped a couple of times just yesterday. A&P is checking it out today. I'll report back on the verdict, but he is saying most likely the pump is bad.

$775 + $42 shipping for a pump exchange from CJ Aviation + R&R by my A&P.

I sent two Dukes pumps to Aeromotors for overhaul. Upon fitting the first one I had the same starting problems that other have previously reported. I checked the the magnetos and ultrasonic cleaned the nozzles. No difference. I then checked the flow at the injector lines and found that with the pump selected to prime I was only getting a drip from one line. I have now fitted the second pump that Aeromotors overhauled and it works perfectly, starting is now back to normal. It seems that an Aeromotors overhaul is a bit of a lottery!

I use the (Dukes) electric boost pump in my DA40 to prime for starting, during takeoff, landing, and when switching tanks. On Wednesday, I used the pump to start the engine, and all appeared to be normal. After starting I turn on the ALT and AVIONICS (with the pump Off). I then taxied to the runup area, and all was normal until I switched the pump on, only to be met with so much static that it was impossible to hear the tower communications. Upon switching the pump off, the RF interference went away. I later checked the pump/interference issue with my plane in my hangar and the engine off, and I encountered the same issue.

Initially, I thought that the problem was either the brushes going on the pump's motor, or some intermittent grounding issue. However, upon removing the inspection/access plate (where the gascolator is located), I saw no issues with any of the wiring, so I assume that the issue is with the pump motor's brushes, even though the pump seems to be working fine. I now have a pump on order that I expect to receive next week. I will report back once it has been installed, but I am hopeful that that will cure the RF problem that only exists when the pump is turned on.

Sandy

Sandy,
Yep, this is one of the failure modes. I had the same thing happen with my first fuel pump. It still worked fine, but couldn't live with the static.

You will be replacing the pump, Sandy. I suggest doing it sooner rather than later.

Yes, Colin, I have already grounded the plane and ordered the replacement. I should have the "new" (newly overhauled by QAA, that is) this week. The access panel is off, and as soon as the replacement pump arrives, and my mechanic is able to come over to my hangar, it will get replaced.

Since I fly out of KPDK, which is the second busiest airport in Georgia (after Atlanta, of course), I really do use the radio. Besides, I don't want to fly somewhere and find that the pump has truly died, whereby I would not be able to restart the engine without being able to prime it.

Sandy

I received the new electric pump yesterday afternoon, and my mechanic and I installed it today. After having read many posts regarding the lack of reliability of the original Dukes pumps, I was somewhat surprised to learn that the reason my logbook had no record of my plane having had a prior electric pump replacement was that it never had one. The pump that we removed had a manufacture date of November 22, 2004, so it was the original pump in my 2005 plane. The pump actually has a notice on it that says it should be replaced/overhauled after 10 years, so having it last for 14 years doesn't seem that bad, particularly since, as I pointed out in my prior post, it never really failed, but the motor must have been going, as the RF noise was significant. All is quiet on the radio with the new pump which has the "B" revision.

Something that I found to be odd about the pump is that while it is operated on a 24V DC system it is agnostic as to polarity, and there was even a sticker to that effect on the wires of the original pump. Changing the pump out took just under two hours, including the time needed to remove the old pump, move the fittings from the old pump to the new one, solder the wires of the new pump onto the harness that was removed from the old pump, and install and leak test the new pump.

Sandy