Best location to place a fuel transducer on a M20E

[Planegofast]

In need of your help again!

I recently bought a used fuel flow meter and I am having a difficult time trying to locate the perfect spot for the fuel transducer.  I have tried to search the forums in the hope of finding that someone else had posted pictures of the install on an IO360.  I could not find any (I can't find a gallon of milk in the refrigerator either)

Is there a location that has worked for you?

 

[ArtVandelay]

Horizontal and stable, mine is on top of the foot well firewall extension box.

[MB65E]

In line between the fuel pump and fuel servo. You’ll need to manufacture two hoses. There are instructions for wrapping the unit in fire sleeve. Mine is supported by clamps and wax lace cord along the left edge of the oil pan with the starter cable. 
-Matt

[Ross Taylor]

In our case, which is a 1966 E, it was put on pilot side foot well extension box as Art mentioned above.  I've also seen installations where it is suspended or tied on the engine, but somewhere in one of the documents it mentioned not mounting it on the engine, so ours is attached to the firewall box.

For that location we ordered two replacement hoses. One 18 in long and one 11-in long. That allowed gentle bends for that location. The 11-in hose went on the inside of the transducer and the 18-in hose went after the transducer.

 

[0TreeLemur]

Google search  "fuel transducer site:mooneyspace.com" turn up a lot.   Example:

 

[carusoam]

Avoid the one where the FF sensor is near the exhaust on the engine... it is an acceptable place... just not preferred...

Technically it is a really dumb place for an expensive heat sensitive device....

It was a common place for somebody to add the sensor without high installation costs...

This was a poor trade for high use costs....  often found out about when hot starts are a pain... 

Modern planes put it back on the firewall, long straight entry and exits, with a slight angle for best bubble handling... all in the install manual....

Best regards,

-a-

[Ross Taylor]

Here are some photos of mine, during the trial fitting process.  In these photos, the transducer is angled downward quite a bit...because it's loose.  Once it was clamped (inside fire sleeve) it's much more horizontal.  We also took this opportunity to clean up and better protect the JPI sensor wiring.

 

[Guest]

Ross,

Your JPI wires normally shouldn’t be tied to your ignition wires.

Clarence

[carusoam]

The high voltage ignition wires are often a source of noise (RF) compared to the tiny voltage thermocouple signals....

Thermal Insulation is helpful to keep fuel from evaporating inside the FF sensor... a challenge after sitting on the ramp after running... (called a hot start challenge)

Great pics, Ross!
 

Great details, Clarence!

Best regards,

-a-

[Ross Taylor]

2 hours ago, M20Doc said:

Ross,

Your JPI wires normally shouldn’t be tied to your ignition wires.

Clarence

Exactly! And thank you. These were the “pre clean up” of that wiring pics. I knew this situation was crap...but should have clarified when I said we cleaned up the wiring...that this was the crap! The post-crap cleanup looks much better. 

On a related note...I changed out my old unreadable JPI 700 for a 730. The case on that is shorter and the wiring harness was pulled so tight from the connectors to the firewall that the connectors wouldn’t reach the 730. Now you see where all the excess wire was...bundled up on the engine side. When we fixed all this, there was plenty of wire to pull through to the panel side...and plug in the 730.

Thanks @M20Doc and @carusoam for spotting all the things! I still plan to post a thorough set of engine compartment pics to see what else I need to address. 

[ArtVandelay]

Mine is mounted via a bracket, done by PO so I don’t know if bracket was fabricated or part of the installation kit.

[carusoam]

@Ross Taylor, note Art’s FF sensor wrapped in silicone rubber...?

That's the insulation that is nice to have to keep the FF sensor from over heating...  No overheating, no fuel vapor bubbles...   

Thanks Tom!

Best regards,

-a-

[Ross Taylor]

On 6/20/2020 at 10:26 PM, carusoam said:

@Ross Taylor, note Art’s FF sensor wrapped in silicone rubber...?

That's the insulation that is nice to have to keep the FF sensor from over heating...  No overheating, no fuel vapor bubbles...   

Thanks Tom!

Best regards,

-a-

Yup! These pics were just the positioning tests, posted for @Planegofast reference - after all this testing, the hoses were installed permanently and a section of 1 1/2 inch fire sleeve was slid over the transducer. The wires were poked through a small hole, sealed with RTV. My fire sleeve is closed off with stainless steel bands and the assembly is adel clamped to the box, with a rivnut (I think?). I should have better clarified that these were not the final pics...just early uncluttered photos to show the fuel line routing and transducer location.

[corvar01]

I am having the same difficulty with my '74 F. The pictures here are nice but per the installation instructions there needs to be a loop after the transmitter if the carb/servo is lower than the transmitter, and due to the Mooney's lack of space between the engine and firewall I am still a bit perplexed about the install. I think I figured it out though. 

Mike

fuel Flow.pdf

[Guest]

I’ve never seen one with a loop in the hose, as you point out there isn’t room.

Clarence