Mooney217RN Posted June 20, 2021 Report Posted June 20, 2021 Fellow Mooniacs, looking for you’re help identifying this problem. On prior occasion, the MP indication on my G1000 has gone erratic to the low side at higher altitudes. Yesterday when flying at 10,500 in some very warm temps (high density altitude), the gauge became erratic again enroute to the SF Bay Area. On my return flight, the gauge indication basically crapped out. As I was l on final approach at my home airport, the MP began to read properly again, so lower throttle setting 10.5” MP, it was working. On departure out of the Bay Area, it was working. Again, conditions causing the malfunction are high altitude, or perhaps high pressure altitude. Density altitude on my arrival was around 8,500’. This morning, when checking the MP in static conditions, it is now reading 23.7, which would be about right considering the current density altitude of 8,700,. So engine running, MP indication errant and not functioning properly. High density altitude and hot ambient temps. Engine running fine considering the hot weather. Any thoughts on the source of the problem would be appreciated. MSC says bad connection. I think bad sensor. Quote
Cruiser Posted June 20, 2021 Report Posted June 20, 2021 Sensor. I have been told putting them in an oven at low temp for a couple hours sometimes works. Quote
Mooney217RN Posted June 20, 2021 Author Report Posted June 20, 2021 31 minutes ago, Cruiser said: Sensor. I have been told putting them in an oven at low temp for a couple hours sometimes works. That’s what I think, the sensor. Quote
carusoam Posted June 21, 2021 Report Posted June 21, 2021 Did you get a new MP sensor with the G3X? when the engine is not running… what were MP and altitude…. (Basic test of the MP system) If you have an MP leak… the MP typical reads higher than actual… A big leak and it will read the outside pressure at altitude. It would be hard to produce power and get a low MP reading… other than a failed sensor… PP thoughts only… Best regards, -a- Quote
Mooney217RN Posted June 21, 2021 Author Report Posted June 21, 2021 @carusoam MP reads 23.7 engine off. Field elevation 5,900’ density altitude 8,700’ 1 Quote
Niko182 Posted June 21, 2021 Report Posted June 21, 2021 seems like a grounding issue to me. Is the connection solid? Have you tried cleaning the connectors, and making sure they're tight? Quote
GeeBee Posted June 21, 2021 Report Posted June 21, 2021 Do a simple condition check of you MP pressure line first. I had similar symptoms once and it was the connection to the manifold itself was loose. Then start messing with the electronics. Quote
Jeff_S Posted June 21, 2021 Report Posted June 21, 2021 MP indication gets screwy on occasion. Just check the cannon plug and make sure it's clean and tight. That fixes 99% of the problems. I hope your sensor isn't bad, because I have learned that Mooney doesn't supply them anymore so it becomes a challenge to swap that out. Quote
Mooney217RN Posted June 22, 2021 Author Report Posted June 22, 2021 Good news/bad news on this. The MP line is fine, the fittings haven't moved and are not loose. The canon jack plug appeared to be seated properly. it was clean. I am going to clean it anyway with contact cleaner and re-connect. Haven't checked the wire harness connections to the plug yet, but they appear to be solid. Looks like both transducers have never been touched since installation on the aircraft at time of manufacture. there is no corrosion anywhere on the plug or sensor. I have the part #, and that's where the bad news starts. The part is no longer manufactured, and there is no replacement part. it's a Kulite Air Pressure Transducer, p/n APT-20G-1000-25A I am crossing my fingers that the contact cleaner will solve the issue, reconnect and I am on my way. If not, we have a major problem. Quote
carusoam Posted June 22, 2021 Report Posted June 22, 2021 possibly good news… You won’t be the first to have a Kulite sensor go awry… A search around here should reveal what other people have done to find a different sensor… Fortunately, the sensor isn’t a very unique device… https://mooneyspace.com/search/?q=Kulite MP&updated_after=any&sortby=relevancy&search_and_or=and Best regards, -a- Quote
Cruiser Posted June 22, 2021 Report Posted June 22, 2021 call Maxwell Aviation, MSC they will have a solution Quote
Jeff_S Posted June 22, 2021 Report Posted June 22, 2021 When I was wrestling with a balky MP again this spring, I told the A/P to clean out the plug but he also did some research on the transducer. Apparently this came up in Beech-land as well, and they seem to have uncovered a solution he found on the web, but it was going to be pricey. If Maxwell has an answer that would be good, and if you find this out please post to the group so we know. Luckily for me, just cleaning the plug fixed it again. That's twice I've done this in 7 years of ownership. I should just add it to the check-off list on the annual. Quote
Mooney217RN Posted June 23, 2021 Author Report Posted June 23, 2021 I cleaned both sides of the plug today with electrical contact cleaner. Reassembled. Worked fine in static and run-up, but haven't flown it yet. I am guessing that it is failing at high altitude and high ambient temps. Interestingly enough, the MP was 24.4 static subsequent to cleaning, 23.7 prior to cleaning, altimeter 30.11 on both occasions. Density altitude was 8,000' after cleaning. The other day when it was 23.7, the DA was 8,700' with the same altimeter setting. Quote
MatthiasArnold Posted June 23, 2021 Report Posted June 23, 2021 I had similar problems with my OP sensor in the past and documented this on MS. Since treating all plugs of the electrical connections (for OP and MAP ) including the ones at the firewall and GEA the problems went away like magic. Best, Matthias 1 Quote
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