LOCOLJ Posted July 7, 2021 Report Share Posted July 7, 2021 Recently, I have been seeing an intermittent fluctuation in a rayjay turbo fuel pump. It is fluctuating from 20-24 psi and does it at altitude with the turbo disengaged (normally aspirated). The aux pump adds 2-3 psi and fuel flow on the G3 appears to be holding steady at 10gph at 10.5k. We have recently sealed up the intake box and replaced the rsa servo for our io360a1a 200 hp engine. My mechanics and others have told me not to worry about it, but it somehow doesn't seem right to me. No blue leakage out of the pump drain at all, and the pump is about 10yrs since overhaul. There is a pressure line from the air box to the pump; could that be leaking and causing this? Or is this normal when I have a sealed system? I am not noticing any fluctuation when flying below 9k normally aspirated, so I don't think I have an air leak in a fuel line. Any help with this would be appreciated. Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted July 7, 2021 Report Share Posted July 7, 2021 4 hours ago, LOCOLJ said: Recently, I have been seeing an intermittent fluctuation in a rayjay turbo fuel pump. It is fluctuating from 20-24 psi and does it at altitude with the turbo disengaged (normally aspirated). The aux pump adds 2-3 psi and fuel flow on the G3 appears to be holding steady at 10gph at 10.5k. We have recently sealed up the intake box and replaced the rsa servo for our io360a1a 200 hp engine. My mechanics and others have told me not to worry about it, but it somehow doesn't seem right to me. No blue leakage out of the pump drain at all, and the pump is about 10yrs since overhaul. There is a pressure line from the air box to the pump; could that be leaking and causing this? Or is this normal when I have a sealed system? I am not noticing any fluctuation when flying below 9k normally aspirated, so I don't think I have an air leak in a fuel line. Any help with this would be appreciated. Mine started doing that a few years ago. I have literally changed or rebuilt every part (including the engine) between the fuel tank and the gauge. Nothing fixed it. Let me know what you find. I hope you don’t spend as much as I have to accomplish nothing. 1 Quote Link to comment Share on other sites More sharing options...
Ragsf15e Posted July 8, 2021 Report Share Posted July 8, 2021 I don’t have a turbo, but my io-360a1a does that as well. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 8, 2021 Report Share Posted July 8, 2021 Hmmmm… What is a RayJay fuel pump? What FP sensor do you have? Or is all of this standard M20E hardware, being flown at standard NA altitudes, with a RayJay turbo installed and not operated? Does the FP stay in the green? The reason for the questions…. There are many more NA M20E MSers to draw experience from… than TN’d IO360 users… Best regards, -a- Quote Link to comment Share on other sites More sharing options...
LOCOLJ Posted July 8, 2021 Author Report Share Posted July 8, 2021 6 hours ago, N201MKTurbo said: Mine started doing that a few years ago. I have literally changed or rebuilt every part (including the engine) between the fuel tank and the gauge. Nothing fixed it. Let me know what you find. I hope you don’t spend as much as I have to accomplish nothing. Glad this is an easy one..... one mechanic indicated that the system is designed to be under pressure, but NA we are pulling vacuum and the fluctuation is the motor calling for fuel? To answer some other questions The rayjay system includes a special fuel pump which has a reference line to the airbox. The original fuel pressure gage is the one I am referring to and it is still in the green 14psi is the min. Until recently, I have not seen this fluctuation, so I am looking for reasons why I am seeing this change before I dismiss it. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 8, 2021 Report Share Posted July 8, 2021 Some fuel pressure sensors…. Have a vent hole. Around here, we have seen a few vent holes get blocked… by people that don’t know there is a vent hole there… Mostly sensors by a particular company used by Bravos…. The sensor has a small computer on board… and may start acting up… I wish I had some better experience to share…. FP info seems to be unimportant to Ovation drivers…. We didn’t get an FP gauge, just FF…. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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