Coincidentally, two RVs here in ABQ have been experiencing a similar issue and we're not sure why. For the first 150-250 hours, the fuel pressure was pretty constant at about 28psi. Now, the fuel pressure bobbles around in cruise between 23 and 28 psi. In my plane, it is not uncommon to see 18-20 psi at some point during climb out, while burning about 12-14 gph. It's even gone as low as 15 psi for a few minutes at a time. Boost pump brings it up to about 20 psi.
Both are RV-7s with Lycoming injected engines, AFP fuel pumps, no gascoltor, and plumbed as per Van's plans. The FF sender is just forward of the fuel pump. Field elevation is 5800 ft.
We spoke to our respective engine builders. One says it should stay steady at 28 psi, the other says it can jump around and operate as low as 14 psi before being concerned. Both are credible sources and reputable engine builders. We're curious what the forum has to say. Is this a leading indicator of mechanical fuel pump failure or normal operation? Thanks in advance.
Both are RV-7s with Lycoming injected engines, AFP fuel pumps, no gascoltor, and plumbed as per Van's plans. The FF sender is just forward of the fuel pump. Field elevation is 5800 ft.
We spoke to our respective engine builders. One says it should stay steady at 28 psi, the other says it can jump around and operate as low as 14 psi before being concerned. Both are credible sources and reputable engine builders. We're curious what the forum has to say. Is this a leading indicator of mechanical fuel pump failure or normal operation? Thanks in advance.