takair Posted October 17, 2020 Report Posted October 17, 2020 On 10/17/2020 at 4:04 PM, 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 Expand Diaphragm style pump, so maybe.... Quote
Prestonalton Posted October 17, 2020 Author Report 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
N201MKTurbo Posted October 17, 2020 Report 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
Prestonalton Posted October 17, 2020 Author Report Posted October 17, 2020 On 10/17/2020 at 7:39 PM, 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. Expand 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
Guest Posted October 18, 2020 Report 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
Prestonalton Posted October 18, 2020 Author Report Posted October 18, 2020 On 10/18/2020 at 1:30 AM, 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 Expand Interesting, what exactly will this do? Clog up where the air is leaking in because of the heavy viscosity? 1 Quote
Prestonalton Posted October 19, 2020 Author Report 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
carusoam Posted October 19, 2020 Report Posted October 19, 2020 On 10/19/2020 at 3:15 AM, 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? Expand 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
gsxrpilot Posted October 19, 2020 Report Posted October 19, 2020 On 10/19/2020 at 3:15 AM, 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? Expand https://visitedstatesmap.com Quote
1964-M20E Posted October 19, 2020 Report 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
takair Posted October 19, 2020 Report 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
Prestonalton Posted November 3, 2020 Author Report 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
carusoam Posted November 4, 2020 Report Posted November 4, 2020 Great follow-up Preston! Thanks for sharing the feedback! Best regards, -a- Quote
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