takair Posted October 17, 2020 Report Share Posted October 17, 2020 2 minutes ago, Prestonalton said: So I am out here checking on the fittings and for leaks right now and noticed the l drain in front of the nosewheel tire is actually plugged up. Would this have anything to do with the issue I am having? Thinking about doing a test run-up after I clear the drain. Picture attached Diaphragm style pump, so maybe.... Quote Link to comment Share on other sites More sharing options...
Prestonalton Posted October 17, 2020 Author Report Share Posted October 17, 2020 Here is a video of a run-up I just did trying to replicate the issue. No fuel or oil leaking anywhere afterwards. The pressure didn’t get as low as it did during my climb out previously but it still seems irregular the pressure is getting so low when power is increased. You can see it comes up quite a bit once I reduced power. IMG_4336.MOV Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted October 17, 2020 Report Share Posted October 17, 2020 I would suspect the fuel selector. Have you switched tanks when this happens? About the only thing that will go wrong with a mechanical pump is the diaphragm will break or the spring will break. If the diaphragm breaks, it will leak out the vent line. If the spring breaks you will have low fuel pressure and no rise from the Electric pump pressure. Your symptoms suggest that you are sucking air somewhere. Usually the fuel selector. I've seen it do that without any visible fuel leaks. 2 Quote Link to comment Share on other sites More sharing options...
Prestonalton Posted October 17, 2020 Author Report Share Posted October 17, 2020 22 minutes ago, N201MKTurbo said: I would suspect the fuel selector. Have you switched tanks when this happens? About the only thing that will go wrong with a mechanical pump is the diaphragm will break or the spring will break. If the diaphragm breaks, it will leak out the vent line. If the spring breaks you will have low fuel pressure and no rise from the Electric pump pressure. Your symptoms suggest that you are sucking air somewhere. Usually the fuel selector. I've seen it do that without any visible fuel leaks. Yes, it is agnostic to fuel tank. That is the first thing I tried when it happened, switching fuel tanks. It happens on both sides. Quote Link to comment Share on other sites More sharing options...
Guest Posted October 18, 2020 Report Share Posted October 18, 2020 Try to dribble some 100 weight oil down the fuel selector shaft to see if it changes the symptoms. It may prove Rich’s theory. Clarence Quote Link to comment Share on other sites More sharing options...
Prestonalton Posted October 18, 2020 Author Report Share Posted October 18, 2020 18 hours ago, M20Doc said: Try to dribble some 100 weight oil down the fuel selector shaft to see if it changes the symptoms. It may prove Rich’s theory. Clarence Interesting, what exactly will this do? Clog up where the air is leaking in because of the heavy viscosity? 1 Quote Link to comment Share on other sites More sharing options...
Prestonalton Posted October 19, 2020 Author Report Share Posted October 19, 2020 Also, off-topic but how do some of you get the states where you've been in the Mooney? Is there a website that does it or something? Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 19, 2020 Report Share Posted October 19, 2020 4 minutes ago, Prestonalton said: Also, off-topic but how do some of you get the states where you've been in the Mooney? Is there a website that does it or something? Preston the search function is pretty good... When your memory isn’t as strong... When you get this part working... Check in with @gsxrpilot to be included in another important map.... This is the map of the home dromes of all the MSers... this can be incredibly helpful for those AOG days... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
gsxrpilot Posted October 19, 2020 Report Share Posted October 19, 2020 19 minutes ago, Prestonalton said: Also, off-topic but how do some of you get the states where you've been in the Mooney? Is there a website that does it or something? https://visitedstatesmap.com Quote Link to comment Share on other sites More sharing options...
1964-M20E Posted October 19, 2020 Report Share Posted October 19, 2020 I experienced this issue as well. I changed the transducer first and it looked like problem was solved. However, it poped up again. I changed the fuel pump and both hoses connected to it. The problem cleared up. However I did get a low fuel pressure alarm again on climb out. Hot day and long climb. I'm wondering if engine compartment heat has anything to do with it? I have the oil cooler relocation so the oil cooler is dumping heat right on my fuel flow sensor. It only recurred once. 1 Quote Link to comment Share on other sites More sharing options...
takair Posted October 19, 2020 Report Share Posted October 19, 2020 Another thing to check is the gascolator. There have been reports of the gasket drawing air under the lower pressure of the fuel pump suction, but not actually leaking fuel. I suppose the drain could have similar effect. Not sure how one troubleshoots that except by removing the bottom and checking the gasket. In my friends case the problem got worse with increased altitude and full power. 1 Quote Link to comment Share on other sites More sharing options...
Prestonalton Posted November 3, 2020 Author Report Share Posted November 3, 2020 Just following up on this thread. The problem was found and fixed! It was a loose connection forward of the electric fuel pump. It was only able to be found when I turned on the boost pump when priming the engine while my mechanic was outside. All the fuel would evaporate when I previously would do this so I had no idea fuel was leaking when priming the engine. We also replaced the mechanical fuel pump and are seeing upwards of 30psi. Much better than it normally read previously. Thanks for all the help on here for what to check and what not. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted November 4, 2020 Report Share Posted November 4, 2020 Great follow-up Preston! Thanks for sharing the feedback! Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.