m32825
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My 803 had a Facet 40193 primary fuel pump installed in it. I was having problems with it dragging down and shutting off after brief periods of load testing. I could not find the recommended AirTex E1074 anywhere. Replacement Facet pumps were over $200, that didn't seem like a good choice given that they replaced it with an AirTex pump. I found that AirTex has a technical support line and they do answer their phones. They recommended an E8131, I got one on Amazon along with a small fuel filter element.
I also ordered a fuel pressure gauge and used a t-fitting to put it in line with one of my injectors so I could see what was going on before and after the replacement.
Here's my original pump:
Here's the pressure with the pump running, but not the engine:
I had about 3.5 psi with fuel flowing through the filters and back to the fuel tank through the return line. When I pinched the return line the dead head pressure was 5.5 psi. I tried running the engine to see what effect it had on the pressure and found that the injector pump action causes the needle to fluctuate from 0.5 psi to 3.5 psi. This is probably not good for the gauge, a damped one might be better, but seeing all the fluctuation was interesting, too. Seems like there's not much fuel pressure margin when the injector pump is running (low pressure close to zero), if things aren't working just right and there's a little more demand the injectors aren't getting what they need.
I swapped out the Facet for the AirTex:
Repeated pressure testing:
I had a bit less than 7 psi with fuel still flowing back to the fuel tank through the return line. When I pinched the return line the dead head pressure was 9 psi. I tried running the engine to see what effect it had on the pressure and found that the injector pump action causes the needle to fluctuate from 3.5 psi to 6.5 psi.
The unit performed well under load testing. I gave it ten minutes at 50%, 85%, 95%, and 115% with no problems. I'm calling the replacement a tentative success, time will tell how it holds up.
-- Carl
P.S. One thing I learned from this effort: when there's a big hurricane headed your direction, no one complains about time spent working on your generator. Stay safe, guys!
I also ordered a fuel pressure gauge and used a t-fitting to put it in line with one of my injectors so I could see what was going on before and after the replacement.
Here's my original pump:
Here's the pressure with the pump running, but not the engine:
I had about 3.5 psi with fuel flowing through the filters and back to the fuel tank through the return line. When I pinched the return line the dead head pressure was 5.5 psi. I tried running the engine to see what effect it had on the pressure and found that the injector pump action causes the needle to fluctuate from 0.5 psi to 3.5 psi. This is probably not good for the gauge, a damped one might be better, but seeing all the fluctuation was interesting, too. Seems like there's not much fuel pressure margin when the injector pump is running (low pressure close to zero), if things aren't working just right and there's a little more demand the injectors aren't getting what they need.
I swapped out the Facet for the AirTex:
Repeated pressure testing:
I had a bit less than 7 psi with fuel still flowing back to the fuel tank through the return line. When I pinched the return line the dead head pressure was 9 psi. I tried running the engine to see what effect it had on the pressure and found that the injector pump action causes the needle to fluctuate from 3.5 psi to 6.5 psi.
The unit performed well under load testing. I gave it ten minutes at 50%, 85%, 95%, and 115% with no problems. I'm calling the replacement a tentative success, time will tell how it holds up.
-- Carl
P.S. One thing I learned from this effort: when there's a big hurricane headed your direction, no one complains about time spent working on your generator. Stay safe, guys!
