Manifold pressure gauge on G1000

[Mlasalle]

Ever since I got my modern glass Mooney 2 years ago, I've had erratic problems with my manifold pressure indicator on the MFD. Several avionics guys have got it working again(a different diagnosis every time), but after a while I start getting erroneous readings again.

It reads a pressure lower than actual, erratic, up and down. The problem has always been a connection somewhere. Usually the large wire harness that goes through the firewall. Take em apart, clean em then back together again and it works fine for a few hours.

There is not a lot of Mooney G1000 avionics repair experience in my area.

Obviously, it's a loose connection, but cannot nail it down.

[29-0363]

Ditto for 29-0363. Have you tried applying contact cleaner to the pins on the bayonet connection? It helps but like you say, the erratic readings reappear.

[Mlasalle]

I don't know which one is the bayonet connection, but I'm sure it's been cleaned. BTY, my avionics guy said never spray corrosion X on connections. It works its way into the circuit boards and eats them up. A garmin no-no. Was told by Premier that hardwiring a separate wire to the MFD, outside the harness, should fix the problem. That means pulling out the panel. I haven't found a technician with the balls to tackle that yet. I'm not sure if I have em,

[Nathan Peterson]

Mlasalle,

 

If you get a chance look at my photo's that I posted and read... I hope this will help you out.  Nate

[Mlasalle]

Thanks Nate, I just figured out the photo thing on the main page and saw your pics.  Imma work on them again.  I noticed you are N490PS, I'm three behind you at N493PS.

[Nathan Peterson]

Mlasalle,

 

I saw the same thing N493PS... I sure hope that helps you out. 

 

Nate

[Nathan Peterson]

What did you come up with?  

[Mlasalle]

I haven't got to it yet. Flew this weekend. It's still bouncing around. I'll give a report as soon as I clean n grease the connections

[Nathan Peterson]

[jeff hodgson]

I have the exact same problem. 2007 o3, this weekend, MP drops, jumps and bounces. I was over mountains at the time so it was very exciting when it first dropped... Soon realized it was just the gauge, but still. What to do now?

[Nathan Peterson]

Mlasalle,

 

What did you come up with?

 

Nate

[neil]

I have the same issue.. Has anyone come up with a solution?

[Bob5151F]

I have had fluctuations on the high and low side.  I even got 32.5" on the takeoff roll, followed by off on high scale (>35). Not bad for a normally aspirated engine. The problem is intermittent and seems to settle down after 10-15 minutes of flying.

[JimK]

Anyone come up with a resolution to this problem yet?

I agree with Bob5151F. My O3 MAP is reading erratic (+\-2”) during the climb, then nearly rock solid for cruise, then erratic again on descent.  
I’ve swapped out the transducer, cleaned connectors, checked all line connections and pulled on all sorts of wires to check for intermittent connections.  None of that pointed to a fix for the problem and now that makes sense to me.  It wouldn’t be any of those things if the problem is almost exclusively in climb and descent.  It must be triggered by changing atmospheric pressure (climb/descent) but somehow linked to a G1000/GEA71 software glitch.  However, I have all the most current software and have talked with Garmin. They gave me some things to try but none worked.

still looking for a fix!

[PT20J]

Have you tried a snubber?