Fuel sending unit intermittent.

[capthaak]

The right side fuel sending unit on my 81J has become intermittent and unreliable. Anyone else have such issues? I would imagine so. How expensive and are there any upgrades?

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[Mooneymite]

Before I did anything too expensive, I'd check the grounding wire for the sending unit.

[laytonl]

Are you sure it's the sending unit and not the gauge?  Poor grounding at the gauge will cause this.  Lee

[Mooneymite]

I don't have a J.  On my C, if the cluster gauge ground is bad, more than the fuel quantity is affected.

I guess checking the ground at both ends makes sense.

[Releew]

I went through this issue........  Happened when the tank levels got below 10 gallons.  The reading was all over the place.  This will be difficult to believe......BUT, since I started adding Marvel Mystery Oil on a regular basis the sending units have been rock solid at any level.  Sticky sensors.....  Don't know.  Do know there was a visual change and is now working on the panel and tank gauges.  Coincidence or real?  

 

Rick

[mooniac15u]

  On 11/1/2015 at 12:48 AM, Mooneymite said:

I don't have a J.  On my C, if the cluster gauge ground is bad, more than the fuel quantity is affected.

I guess checking the ground at both ends makes sense.

On the J each of the gauges grounds through the sensor.

[tony]

  On 11/1/2015 at 3:08 AM, Releew said:

I went through this issue........  Happened when the tank levels got below 10 gallons.  The reading was all over the place.  This will be difficult to believe......BUT, since I started adding Marvel Mystery Oil on a regular basis the sending units have been rock solid at any level.  Sticky sensors.....  Don't know.  Do know there was a visual change and is now working on the panel and tank gauges.  Coincidence or real?  

 

Rick

I'm getting ready for the entertainment to follow.....

[Releew]

Yeah me too......  But no kidding.  I can't pinpoint it, but that's the ONLY change in routine.

If you're old-school, you know MMO can perform miracles!!!

[carusoam]

A supplier of modern fuel senders has been on here recently posting the value of his new devices....

could be worth a search here on MS.  Especially if you are using a digital device like a JPI to show fuel levels.

best regards,

-a-

[Deb]

  On 11/1/2015 at 4:48 PM, carusoam said:

A supplier of modern fuel senders has been on here recently posting the value of his new devices....

could be worth a search here on MS.  Especially if you are using a digital device like a JPI to show fuel levels.

best regards,

-a-

He's Scott Philiben of CIES. He posts on Beechtalk. Here's a thread:

http://www.beechtalk.com/forums/viewtopic.php?f=7&t=103920&view=unread#unread

He makes senders for Cirrus and some Beechcrafts. He may be able to supply some Mooney models. A 337 is probably involved.

[carusoam]

D,

I ran out of time today to finish the post...

I am pretty sure he gave some background on his company and products here, somewhere.

Unfortunately, I am unable to find the details of what I saw.

Best regards,

-a-

[laytonl]

  On 11/1/2015 at 12:39 PM, mooniac15u said:

On the J each of the gauges grounds through the sensor.

I believe the signal does ground through the sensor at the outboard sender.  However the display itself is powered and grounded at the instrument cluster.  Or at least this is how I understand it.  I've seen gauges settle down with improved grounding at the instrument cluster.  The problem could be a poor ground in the sender circuit or a flaky ground at the cluster.  Lee

 

 

[mooniac15u]

I'm not sure where that diagram is from but here's the schematic for the cluster gauge for the OP's S/N.  You can see that there is power connected across all the gauges and then each has an individual ground that connects to the sensor on another part of the schematic.  The fuel gauges have a second connection to the annunciator panel for the low fuel lights. There is no common ground for the cluster.

I suspect that the ground in your diagram may be for the lights.  The cluster gauge was not lighted in 1981.

Edited November 5, 2015 by mooniac15u

[Eraaen]

  On 11/1/2015 at 3:08 AM, Releew said:

I went through this issue........  Happened when the tank levels got below 10 gallons.  The reading was all over the place.  This will be difficult to believe......BUT, since I started adding Marvel Mystery Oil on a regular basis the sending units have been rock solid at any level.  Sticky sensors.....  Don't know.  Do know there was a visual change and is now working on the panel and tank gauges.  Coincidence or real?  

 

Rick

Interesting, I've had the same issue on the left tank below about 9-10 gallons.  Will start bouncing and all of the sudden "Make Gas."  It will show I have 18 gallons or so.  What kind of dilution ratio do you use.  Any other concerns about adding Mystery Oil to the Fuel? Sounds a little strange to me.

Edited November 5, 2015 by Eraaen

[Bob - S50]

  On 11/2/2015 at 12:11 AM, Deb said:

He's Scott Philiben of CIES. He posts on Beechtalk. Here's a thread:

http://www.beechtalk.com/forums/viewtopic.php?f=7&t=103920&view=unread#unread

He makes senders for Cirrus and some Beechcrafts. He may be able to supply some Mooney models. A 337 is probably involved.

I've been following his thread (I actually started it) on Beechtalk.  He has units for K and newer available now.  $395/sender for a total of $1580 but you cannot use the stock fuel gauge.  The cheapest way to use his senders is to buy an Aerospace Logic FL252 for $651.  That's a total of $2231 + any taxes + shipping + install.

For the J and earlier he says there is a problem with the inboard senders.  Apparently some (or all?) have some tubing in the wing that requires the float arm to be angled to clear the tubing.  Not sure how to tell which specific aircraft have angled and which have straight without removing the float to look at it.  If it is straight, we can probably use the floats he sells for the K and newer.  If it is bent he basically gives me two choices.  Make one set just for me at about $650 for one inboard sensor, or find 50 or more owners who want his floats.  In that case the cost comes down to about $415 for each inboard float.  Makes it $1620 plus everything else.

I would love to have his floats as it should produce a fuel gauge accurate to within 0.2 gallons or so, as long as you calibrate the system properly when you install it.

Are there 50 other J and older owners interested in spending $2500 - $3000 or so for an accurate fuel gauge?

Does anyone know of a way to check the inboard sender geometry without removing it?  Tried digital photo (rib in the way).  Borescope equipment?  Something else?

Bob

[Releew]

  On 11/5/2015 at 1:42 PM, Eraaen said:

Interesting, I've had the same issue on the left tank below about 9-10 gallons.  Will start bouncing and all of the sudden "Make Gas."  It will show I have 18 gallons or so.  What kind of dilution ratio do you use.  Any other concerns about adding Mystery Oil to the Fuel? Sounds a little strange to me.

I add MMO based off the label recommendations.  I have use it in every aircraft I've owned along with several others I know in aviation. It's proven itself to me but is definitely a personal choice.  When I initially purchased the Mooney I did not use it.  Just happened to have some in the cabinet, used it and the fluctuation ended. 

I question it myself to whether this actually fixed something that was sticking mechanically, but the difference is real, no more bouncing on the instrument gauge!

It's the only two dots I can connect........

Rick

 

[jclemens]

If your issue is the sending unit you can try taking it out and cleaning it.  Go to the hardware store and buy yourself some naval jelly, it a thick hydrochloric acid gel used to remove rust stains. Once you have the sending unit in you hand fill the end of it where the arm pivots full of the stuff and move it back and forth.  Repeat this process for a few minutes.  Rinse thoroughly with hot water.  A second application is goods practice.  Reinstall.  You can see if this will help you and whether or not it worked with a multimeter.  Connect one lead to the center terminal and the other to the body of the sender.  Set the meter to read ohms.  The reading should range from 20 to 270 or so when the arm is moved through its full travel.  The numbers are not really the important part in this case, what your looking for a is a constant, smooth increase or decrease in the reading.  Anytime the resistance jumps around non-linearly this will be shown on your gauge as a jumpy needle.  You can repeat this test after the cleaning and see your results.  

[carusoam]

Great tech info, JC!

Best regards,

-a-

[mooniac15u]

I believe naval jelly contains phosphoric acid rather than hydrochloric acid. 

[StevenL757]

  On 10/31/2015 at 9:40 PM, capthaak said:

The right side fuel sending unit on my 81J has become intermittent and unreliable. Anyone else have such issues? I would imagine so. How expensive and are there any upgrades?

 

 

Sent from my iPad using Tapatalk

So, hopefully I can offer something constructive, and paraphrasing a lot of what Bob says above.  Most of us know this has been a recurring problem with many Mooney models for years, and my frustration level finally grew to the point where I found out about CIES and their work with Cirrus, and had to engage them.

For the last couple of years, I've been working on and off with Scott, Richard, Charlie, and the team in Oregon to help drive the process of researching, designing, and manufacturing the first set of digital transmitters for my Ovation.  The team finally delivered on that commitment, and attached are pics of both my existing and new digital transmitters.  Credit also goes to Paul Beck at Weep No More and Brian Kendrick of Mooney Support, Inc. They spent many hours of their valuable time to answer questions, attend conference calls, and consult on the installation and technical details regarding connectivity options for the Ovation and other platforms.  Unfortunately, I can't give a PiREP, as I still have yet to carve out time to get these things installed.  My schedule just  hasn't permitted it.  The transmitters will be connected to my EDM930, and then calibrated to indicate 51USG per side.  I've attached the installation guide (available on CIES' website).  Specific schematics and such should be obtained from Scott directly.  I can't emphasize enough how much help he and their company have been, and I strenuously urge anyone who is experiencing this problem (or has been experiencing it for awhile) to contact Scott in Oregon as soon as possible, discuss your situation, and see what he can do for you to get a permanent solution in place.  Not to impune repair efforts offered by other here - I'm sure they are all valid and cost-efficient - but after seeing them in action on several Cirrus models (the CIES transmitters are TC'ed and deployed on all new Cirrus airplanes, and have been retrofitted on hundreds more already in service), I can only hope my individual case is just as successful.

So - No more sticky transmitters?  Yes.  You can now have that.  Happy to help anyone in particular if you decide this avenue may be right for you.  Nothing in it for me, other than helping someone have as exceptional an experience with CIES as I've had so far.

-Steve

Installation Requirements-CC Series Fuel Senders _ Rev A.pdf

Edited November 7, 2015 by StevenL757

[Marauder]

  On 11/7/2015 at 2:16 AM, StevenL757 said:

So, hopefully I can offer something constructive, and paraphrasing a lot of what Bob says above.  Most of us know this has been a recurring problem with many Mooney models for years, and my frustration level finally grew to the point where I found out about CIES and their work with Cirrus, and had to engage them.

For the last couple of years, I've been working on and off with Scott, Richard, Charlie, and the team in Oregon to help drive the process of researching, designing, and manufacturing the first set of digital transmitters for my Ovation.  The team finally delivered on that commitment, and attached are pics of both my existing and new digital transmitters.  Credit also goes to Paul Beck at Weep No More and Brian Kendrick of Mooney Support, Inc. They spent many hours of their valuable time to answer questions, attend conference calls, and consult on the installation and technical details regarding connectivity options for the Ovation and other platforms.  Unfortunately, I can't give a PiREP, as I still have yet to carve out time to get these things installed.  My schedule just  hasn't permitted it.  The transmitters will be connected to my EDM930, and then calibrated to indicate 51USG per side.  I've attached the installation guide (available on CIES' website).  Specific schematics and such should be obtained from Scott directly.  I can't emphasize enough how much help he and their company have been, and I strenuously urge anyone who is experiencing this problem (or has been experiencing it for awhile) to contact Scott in Oregon as soon as possible, discuss your situation, and see what he can do for you to get a permanent solution in place.  Not to impune repair efforts offered by other here - I'm sure they are all valid and cost-efficient - but after seeing them in action on several Cirrus models (the CIES transmitters are TC'ed and deployed on all new Cirrus airplanes, and have been retrofitted on hundreds more already in service), I can only hope my individual case is just as successful.

So - No more sticky transmitters?  Yes.  You can now have that.  Happy to help anyone in particular if you decide this avenue may be right for you.  Nothing in it for me, other than helping someone have as exceptional an experience with CIES as I've had so far.

-Steve

Installation Requirements-CC Series Fuel Senders _ Rev A.pdf

Thanks for the insight. Would love to hear a PIREP when you have them installed. As a long time owner, I really never had a reason to trust the fuel gauge and have flown for years relying on the accuracy of either my inflight calculated burn per hour or for the last 20 years on fuel flow determined by the fuel totalizers (I have two now).

With the granularity of the JPI 900's fuel gauge, I would love to get more precise information but when they posted their expected prices, just a bit hard to justify the expense. Hopefully there is a way to bring it down a bit or a group buy opportunity in the future.

Sent from my iPad using Tapatalk

[Bob - S50]

Here us a graph taken from the BeechTalk forum showing fuel level performance using the Cies floats.  The orange line is fuel level  in one tank and the blue line is fuel level in the other tank.  He reports that this was done during a flight in turbulence.  He also says that when both tanks vary in essentially the same direction, it is due to turbulence.  When they vary in opposite directions, it is due to being in a turn.  I find it especially interesting to look at the last portion of the graph.  I assume that is during flight in smooth air.  Note how the blue line is almost perfectly flat while the orange line is almost a perfect slope as fuel is burned from that side only.

[fuellevel]

These senders were developed by Mooney aircraft in 1999 and turned over to International Avionics, the company that manufactures your annunciator and we purchased the patents from them in 2012. 

Here is a more typical 2 hour flight.   Pricing,  and this is obvious to me, CiES senders are FAA TSO'd, which not only were they produced to a FAA approved design,  but also to a FAA approved quality system.  This is different than any other sender available in GA.   These senders utilize a non contact high reliability sensor system and not a potentiometer to determine fuel level.    The TSO designation assures quality output within 0.75% of total tank volume.

I really don't like to denigrate competition,  but the above sender is a whole word away from the tractor senders available for Mooney replacement.  The fact that new CiES senders are priced presently $100 above a rebuilt set of tractor senders for your aircraft is a screaming bargain in aviation terms.  

Right now you can get them direct from CiES, I would not expect that in the future.   The aviation market s not the flat screen TV market, so waiting for the price will come down is a not a reality, as either there is a market or their isn't.  There really isn't enough interest or customers to form a snowball effect.  Our advantage is that we consistently produce senders for the OEM market.   This is the economy of scale that allows us to be price competitive with simple potentiometer senders. 

Yes we will probably be the OEM sender on whatever new GA to light jet aircraft as we offer real performance and value.

We will then leave the determination of whether there is an aftermarket component will be left up to the aircraft manufacturer.  

As for lower priced competition, with a TSO designation, I don't see that on the horizon.  We have the lion share of OEM GA.

 Accurate fuel level,  unlike ADS-B is not likely to be required. 

As for Marvel Mystery Oil - I used it in my Spica Injected Alfa Romeo as insurance for mechanical pump lubrication 

I would only ultrasonically clean legacy senders - the copper allow in the wiper will erode precipitously with the ideas presented in this post 

 

 

 

[carusoam]

Great input, people.

Steve, I'm looking forward to your progress.

Best regards,

-a-

[StevenL757]

So am I.  :-)

Will pass along as soon as possible.