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Fuel Pressure Sensor Failed


ZamF16

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https://kulite.com//assets/media/2017/06/Aircraft-Generic.pdf

Can’t find the Mooney specific version on their site...

https://kulite.com/?type=catalog&s=Apt

Some interesting details...

The only way I can tell the sensor is vented...

It has two etched stripes around its body....

The vent hole is in the center of the stripes.

There is quite a bit of electronic parts residing inside the can.... looks like a Wheatstone bridge in there...

Our gauges are selected to read PSIG...   psi-gauge.... meaning the pressure being read is independent of where the gauge is... this is important as our gauge is going through some atmospheric pressure change that we don’t want to be part of the reading...

MBTF... is a gigantic number... that obviously doesn’t include the number of T/Os our particular sensor sees...

best regards,

-a-

APT-153-1000-30psig

An example of the standard APT series of sensors is below...

3F008076-9320-47B8-866D-7BFAC66AF693.png

990D2EF5-98A3-4EAE-93B8-F6525068B4D1.png

5321DC25-0229-4794-84FB-6EE3D5A9D3BB.png

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22 minutes ago, Don Bishop said:

The Kulite is part number:  APT-153-1000-30psig

The fuel pressure Omega part number is PX309-030GV for cable, PX319-030GV for mini DIN conection and PX329-030GV for twist-lock connection. See the attached catalog pages. I had to go look this up again since it has been a few years. I can't remember now for sure but I believe the pipe threads might need an adapter.

Since the Mooney drawing 940183 says you can retrofit the OP and MAP for an M20M, M20R and M20S with Omega parts it doesn't seem much of a stretch to use Omega for fuel pressure. Maybe there is something different about fuel pressure other than the range but I couldn't see it comparing specs.

Jim

PX309-100mv.pdf Transducer Replacement.pdf

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On 6/20/2020 at 12:58 PM, drstephensugiono said:


320d4aa2543b4e4fdeb7944a31327781.jpg
e765091b500709642c6da155cde6930e.jpg


Sent from my iPhone using Tapatalk


Dr. Stephen seems to be using a different sensor than the other Bravo owners...

his has a wire exiting the side of the body... And it’s label, not completely readable, but has a different code...

 

Best regards,

-a-

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The other sensor...

Druck, is a baker Hughes product...

https://www.bakerhughesds.com/sites/g/files/cozyhq596/files/2019-06/druck_pressure_takes_flight_brochure.pdf

 

Getting closer, but no real definitive answers...

Looks like either one fails after a couple of decades...

No low cost alternative seems to be available on the open market...

Best regards,

-a-

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  • 7 months later...

The fuel pressure indication on my 1994 M20J quit. I made some voltage measurements and determined that it was the Kulite transducer that had failed. Mooney no longer supplies these. The Kulite part number (APT-153-1000-30PSIG) was special built for Mooney. Kulite wouldn't give me the specs or confirm that it has an equivalent standard part. It appears that it is standard except for having a cable connection rather than a connector. Omega was much easier to deal with. I purchased a PX309-030GV. It has a cable connection and is the same physical size and electrical specs as the original (Wheatstone bridge, 10V excitation, 100 mv output at 30 PSIG). The only difference from the Kulite is that the Omega has a NPT nipple whereas the Kulite has a flare nipple. This necessitated installing a #4 FNPT to #3 AN flare adapter. So, I removed the CPC connector from the old transducer cable, installed it on the new transducer cable, installed the adapter on the new transducer, installed it in the airplane, verified that it read the correct pressure and my IA agreed it was an owner produced part.

The Omega part was $209.45, has a six day lead time (they build them to order) and came with a calibration record traceable to NBS.

Skip

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2 hours ago, PT20J said:

The fuel pressure indication on my 1994 M20J quit. I made some voltage measurements and determined that it was the Kulite transducer that had failed. Mooney no longer supplies these. The Kulite part number (APT-153-1000-30PSIG) was special built for Mooney. Kulite wouldn't give me the specs or confirm that it has an equivalent standard part. It appears that it is standard except for having a cable connection rather than a connector. Omega was much easier to deal with. I purchased a PX309-030GV. It has a cable connection and is the same physical size and electrical specs as the original (Wheatstone bridge, 10V excitation, 100 mv output at 30 PSIG). The only difference from the Kulite is that the Omega has a NPT nipple whereas the Kulite has a flare nipple. This necessitated installing a #4 FNPT to #3 AN flare adapter. So, I removed the CPC connector from the old transducer cable, installed it on the new transducer cable, installed the adapter on the new transducer, installed it in the airplane, verified that it read the correct pressure and my IA agreed it was an owner produced part.

The Omega part was $209.45, has a six day lead time (they build them to order) and came with a calibration record traceable to NBS.

Skip

This is good information.

Do you think Omega could make one for the Bravo?

Its a higher pressure, I think 50psi.

I had a custom probe made by Omega and they were also great to work with.

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8 hours ago, drb930 said:

This is good information.

Do you think Omega could make one for the Bravo?

Its a higher pressure, I think 50psi.

I had a custom probe made by Omega and they were also great to work with.

Omega makes a wide range of pressure ranges including 0-50.

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Omega instruments is a giant in the industrial instrument business...

They had really big catalogs before the internet was born...

https://www.omega.com/en-us/


They may have rebranded other manufacturers such as Dynisco...

Expect that they have what you are looking for.  Attention to tiny details will be very helpful...

 

Owner supplied parts... was invented for this reason.

PP thoughts only, not an active chemical engineer...

Best regards,

-a-

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On 3/15/2021 at 12:40 PM, LANCECASPER said:

I have a Kulite Fuel Pressure transducer just removed for an upgrade for the Bravo if anyone needs one. It has 730 hours on it.

Also interested, if you have not sold it.

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On 8/5/2020 at 9:44 AM, Don Bishop said:

Thank you, Jim!  That was exactly the information I needed.  I'll post again after getting the UMA transducer and let everyone know how it went.

 

Don, did you ever get the UMA transducer installed and working?

Dave

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On 3/18/2021 at 5:10 PM, ZamF16 said:

Don, did you ever get the UMA transducer installed and working?

Dave

Hi Dave!  No.  UMA said they could make the transducer, and we sent them the specs.  They promptly said they could not make it.  Kulite said they could make me one, but I had to buy five at $7020.00 each.  JPI customer service was so bad, I decided to go with EI and put in a whole new engine management system.  Solved the problem.  

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  • 4 weeks later...

There is a SI fix for the Kulite pressure transducers - change the wiring connectors.

Some possibly new info on both the fuel and oil pressure transducer front. My fuel pressure indication slowly decayed to ZERO yesterday. I talked to Lynn at AGL Aviation today and he sent me the attached SI from Benz Airborne Systems, the company that bought(?) the Kulite business. They've traced most failures to the original Mooney OEM connectors and provide guidance on using an alternate wire connection method that should resolve 90% of the issues people are seeing. A lot of folks were already on the right track with taking the OEM connector out of the circuit and splicing or using other better sealed connectors.

It's in the SI, but the Reader's Digest version is that this applies to both the fuel and oil pressure transducers, and failure modes include fluctuating indications, decaying indications, and pegged indications both high and low depending on which wire connections are involved.

Simple fix for what had become a big problem.

Thanks @AGL Aviation!

Cheers,
Rick

BENZ AIRBORNE-KULITE TRANSDUCER.pdf

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On 3/15/2021 at 1:40 PM, LANCECASPER said:

I have a Kulite Fuel Pressure transducer just removed for an upgrade for the Bravo if anyone needs one. It has 730 hours on it.

 

image.thumb.png.ba998faa972bb5457950903818e13111.png

image.thumb.png.3deb744289581effe677a693a72c6ffd.png

 

https://www.ebay.com/itm/114615261419

Feel free to make an offer via PM on here.

Hey Lance, where was the connector for your fuel pressure transducer located in the engine compartment? I tried to trace the wire from mine to the connector tonight but it looks like it goes into a bundle and straight to a firewall through connector. That seems weird to me so I think I’m missing something and would like to localize my search. My next step is to tear into the wire bundle to separate out and trace the transducer wire.

@LANCECASPER

Thanks for any help!

Cheers,
Rick

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23 minutes ago, Junkman said:

Hey Lance, where was the connector for your fuel pressure transducer located in the engine compartment? I tried to trace the wire from mine to the connector tonight but it looks like it goes into a bundle and straight to a firewall through connector. That seems weird to me so I think I’m missing something and would like to localize my search. My next step is to tear into the wire bundle to separate out and trace the transducer wire.

@LANCECASPER

Thanks for any help!

Cheers,
Rick

The oil transducer is easy, it's up on top in the bundle, but the fuel pressure transducer should be behind and below the intercooler.

 

152540580_ScreenShot2021-04-13at10_37_18PM.thumb.png.37b718daf4d0a5eb642192fcb83516a7.png

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15 hours ago, LANCECASPER said:

The oil transducer is easy, it's up on top in the bundle, but the fuel pressure transducer should be behind and below the intercooler.

Thanks. I've traced the wire from the fuel pressure transducer back into a wire bundle and will have to break the bundle open to find out where it goes. I can't see anywhere along that bundle where a wire breaks out to a connector before the firewall. This should be fun.

Cheers,
Rick

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3 hours ago, Junkman said:

Thanks. I've traced the wire from the fuel pressure transducer back into a wire bundle and will have to break the bundle open to find out where it goes. I can't see anywhere along that bundle where a wire breaks out to a connector before the firewall. This should be fun.

Cheers,
Rick

Sorry I misunderstood, I guess I read it too quickly, thought you were looking for the transducer itself.

I'm pretty sure the connector was buried in that bundle, but If not I wonder if they have already taken that connector off and done the service instruction you mention. If you still have the cluster gauges the wires have to go through that big connector on the firewall, so somewhere between there and the transducer . . .  happy hunting . .lol.

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On 4/14/2021 at 8:37 PM, Junkman said:

SUCCESS - fuel pressure transducer connector was cleverly hidden below the oil pressure transducer connector and bundled wire, all zip tied to the engine mount.

A follow-up and clarification on how I fixed my fuel pressure indication anomoly. Hopefully it will save someone else some work and expense.

Bottom line up front - I cleaned the original OEM connectors with contact cleaner, checked the security of wires to pins, reconnected everything and the cockpit fuel pressure indication ops checked GOOD.

To recap the symptoms I've had that were remedied by cleaning the connector:

1. Fuel pressure pegged high (two years ago)
2. Decaying fuel pressure
3. Zero fuel pressure

I opened the connectors expecting to find some obvious corrosion or a loose wire but instead found very clean-looking connector pins and sockets and solidly connected wires. I didn't inspect with a magnifying glass but I have to assume there was some light surface corrosion that I couldn't see, based on my results. I sprayed both connectors with contact cleaner and reassembled the connector just to see if that would fix the issue without cutting any wires to install new connections. Electric boost pump pressure indicated a solid 50psi on the ops check, and the engine driven fuel pump indicated a solid 30psi on the test run and two subsequent flights.

So don't pitch your fuel pressure transducer without doing some work on the connectors first unless you've verified the transducer itself is indeed bad. This may include executing the Benz Airborne SI I linked in a previous post that recommends replacing the OEM connector. If I have another recurrence I'll install the new connections called out in the SI. It looks to be about a 30 minute job.

Cheers,
Rick

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