Fuel Pressure needle reversed ‘64 M20E

[Chocks]

Little help. Just got the aircraft and going through my punch list after some research.

FP/MP combo gauge. Fuel pressure needle is upside down and mirrored on wrong side of gauge. Fuel pressure indication is correct, but mirrored across gauge. 

Need to clean gauge fitting? Flip the needle how? Failing gauge? Just replace it?

Attached a quick vid and thanks for any help. 

[carusoam]

If you have an instrument shop on the field...

That would be a quick one...

The instrument comes out...

The shop probably has special tools to unscrew the face off the instrument...

If the needle got swapped...

It would be pretty easy to put right again...

Expect that it may have something a bit more challenging or Steve would have done it already... 

So while looking closely at that one...

Check in with @Alan Fox for getting a different one...

Best regards,

-a-

[N201MKTurbo]

Did someone put the fuel pressure fitting in the vent hole?

[InJuRo]

Did you change any other connections? Both instrument are connected through the firewall and with the older Mooneys the fuel pressure may be taken from the distribution spider on top of the cylinder. There the pressure at the spider distribution port is lower than at the fuel pressure port, so if connectors or tubing were changed, there may be a wring pressure for the instrument and it goes on "max"?

I had this issue when I got an EDM. When you connected it to the former pressure line of the instrument, the reading was minimal as pressure was taken from the distribution spider. Do you have a EDM installed?

Ingo

Edited May 6, 2021 by InJuRo

[InJuRo]

One more thing.... Does it change when you turn the electrical pump on?

[Shiny moose]

Well I got one from my F if you need one 125 shipped 

[MIm20c]

I’d replace the gauge with cheap used unit. However, this is Mooneyspace so I’ll recommend a G3x with EIS to replace that gauge. 

[Jim Peace]

was it serviced by certain MSCs?

[Yetti]

So I was taxing around and smelled fuel more than I should.   Finally looked over to see fuel dripping out of the panel on the Starboard side.    I am guessing the thing in the back of the gauge had popped.   So that is bad.

There is also hot oil going over to the oil pressure gauge.

So luckily I just finished the hook up to the Dynon skyview EMS.

Would highly recommend getting the fuel and oil back to the other side of the FIrewall and going electric.

Small rant.   The pin mapping and the Skyview manual were off and spent like way too many hours figuring out that my wiring was not wrong and the Pin mapping in the unit was wrong.   Grrrrrr

[InJuRo]

7 hours ago, Yetti said:

So I was taxing around and smelled fuel more than I should.   Finally looked over to see fuel dripping out of the panel on the Starboard side.    I am guessing the thing in the back of the gauge had popped.   So that is bad.

There is also hot oil going over to the oil pressure gauge.

So luckily I just finished the hook up to the Dynon skyview EMS.

Would highly recommend getting the fuel and oil back to the other side of the FIrewall and going electric.

Small rant.   The pin mapping and the Skyview manual were off and spent like way too many hours figuring out that my wiring was not wrong and the Pin mapping in the unit was wrong.   Grrrrrr

If I remember correctly there are two fuel lines on the back of the instrument. One to the instrument and one "vent line" back through the firewall which should end somewhere on the belly in front of the gear. In case the inner membrane of the instrument brakes and the fuel "passes through" it is then cleared through the vent line.

When the EMS was hooked up, did you you use the same fuel pressure port for both instruments?

[Yetti]

7 hours ago, InJuRo said:

If I remember correctly there are two fuel lines on the back of the instrument. One to the instrument and one "vent line" back through the firewall which should end somewhere on the belly in front of the gear. In case the inner membrane of the instrument brakes and the fuel "passes through" it is then cleared through the vent line.

When the EMS was hooked up, did you you use the same fuel pressure port for both instruments?

Apparently mine was vented to the cabin.   Both instruments?   The fuel line off the servo was rerouted to the Dynon KAVLICO FUEL PRESS SENSOR and no more engine fluids go into the cockpit area.

There are two lines that can vent fuel from the engine area.   One off the sniffle valve the other off the mechanical fuel pump

 

[Chocks]

On 5/6/2021 at 5:29 AM, InJuRo said:

Did you change any other connections? Both instrument are connected through the firewall and with the older Mooneys the fuel pressure may be taken from the distribution spider on top of the cylinder. There the pressure at the spider distribution port is lower than at the fuel pressure port, so if connectors or tubing were changed, there may be a wring pressure for the instrument and it goes on "max"?

I had this issue when I got an EDM. When you connected it to the former pressure line of the instrument, the reading was minimal as pressure was taken from the distribution spider. Do you have a EDM installed?

Ingo

I'll check that. Yes I do have an EDM installed.

On 5/6/2021 at 5:31 AM, InJuRo said:

One more thing.... Does it change when you turn the electrical pump on?

Yes, it increases slightly, as expected with the pump on... of course mirrored on the opposite side.

[Chocks]

On 5/6/2021 at 7:27 AM, MIm20c said:

I’d replace the gauge with cheap used unit. However, this is Mooneyspace so I’ll recommend a G3x with EIS to replace that gauge. 

Soooo, the second I can put the GFC500 in my serial #131 E model, that will absolutely happen! 

[Chocks]

@Shiny mooseI'm saving your info for now. I'm gonna try one possible solution next week. If that doesn't work, we'll send you some of that digital cashola

[InJuRo]

On 5/8/2021 at 4:19 AM, "Chocks" said:

I'll check that. Yes I do have an EDM installed.

Yes, it increases slightly, as expected with the pump on... of course mirrored on the opposite side.

Increase in this case means that the indicator moves "down" or "up". I am not totally familiar with the mechanical construction of the instrument but if it moves "down" when you put the switch on, really check if it is simply connected the wrong way around, meaning vent and pressure port were mistaken.

I add some pics of my old instrument. I also did a short test and blew (with the mouth) some air in the vent port connection. Et voilà! This caused exactly what you indicated, the needle reversed (went to the left). So I guess there is a high chance that one of the connections is wrong.

There are ports on the back of the instrument, which are labeled MAN (Manifold), FUEL (Fuel in) and VENT (Fuel Vent port). They may be misconnected there or at the connection which goes through the firewall and will normally be slightly on the right half of the firewall (sie top of arrow).

Ingo

 

[75_M20F]

On 5/12/2021 at 5:27 AM, InJuRo said:

Increase in this case means that the indicator moves "down" or "up". I am not totally familiar with the mechanical construction of the instrument but if it moves "down" when you put the switch on, really check if it is simply connected the wrong way around, meaning vent and pressure port were mistaken.

I add some pics of my old instrument. I also did a short test and blew (with the mouth) some air in the vent port connection. Et voilà! This caused exactly what you indicated, the needle reversed (went to the left). So I guess there is a high chance that one of the connections is wrong.

There are ports on the back of the instrument, which are labeled MAN (Manifold), FUEL (Fuel in) and VENT (Fuel Vent port). They may be misconnected there or at the connection which goes through the firewall and will normally be slightly on the right half of the firewall (sie top of arrow).

Ingo

 

 

Where is the vent line plumbed to? On my F model there is just a plug in the vent port on the back of the gauge.

[InJuRo]

The Vent line goes to the belly of the front cowling and then ends "in the air", so that fuel simply "gets out". There is no connection to anything on the other side after it went through the firewall.

 

Ingo

Edited May 14, 2021 by InJuRo

[Chocks]

Now that I'm moved into my new hangar, I'm gonna finally pull the gauge next week and check it. So @Shiny moose you still got that combo gauge for sale just in case I need it?

[N201MKTurbo]

2 hours ago, "Chocks" said:

Now that I'm moved into my new hangar, I'm gonna finally pull the gauge next week and check it. So @Shiny moose you still got that combo gauge for sale just in case I need it?

No, I bought it. But it didn’t fix my problem. If you need it let me know and I’ll ship it to you for the same price.

It seems to work fine.

[Shiny moose]

Sorry, I have been gone and didnt see the question. Looks like turbo answered it for you. 

[Chocks]

On 5/31/2021 at 6:35 PM, N201MKTurbo said:

No, I bought it. But it didn’t fix my problem. If you need it let me know and I’ll ship it to you for the same price.

It seems to work fine.

I'll take it if you haven't offloaded it yet. Let me know and I'll DM you my info.

[N201MKTurbo]

39 minutes ago, "Chocks" said:

I'll take it if you haven't offloaded it yet. Let me know and I'll DM you my info.

It’s in the plane, I have to swap it out with the original. I’ll try to get to it this week. 

[Chocks]

No rush. I’m having the fuel divider rebuilt anyway. And I doubt I’ll mess with it until after OSH. 
Let me know where to send you money when ready. 

[Chocks]

Hey @N201MKTurbo, totally forgot to update you. Gauge worked perfect for what I needed. Thank you!

[carusoam]

Hey!

A real Chocks sighting! 
 

 

Best regards,

-a-