What are the odds?

rv3flier · #1 10-26-2015, 03:25 PM

What are the odds that two days after flying with no issues, that upon turning on the master sw, there's no clacking noise indicating that the Facet fuel pump is working. So, then I start the engine using it's fuel pump only and my oil pressure reads "0" ziltch, nada. Two failures at once and apparently unrelated.

Too bad the RV-12 design didn't include and isolation shut off between the fuel tank and the fuel pump. It makes a relatively simple job very time consuming.

Then, I find that Rotax has changed the supplier for the pressure sender and that, while the new Keller sender and it's wiring harness can be had from Aircraft Spruce in europe for $190, Lockwood wants $360 !!!! It feels like being held hostage.

OK, rant over.

Has anyone noted that the new Keller sender uses the bottom of its range of 4 ohms to show .75 BAR (about 11 psi) and not Zero like the old Honeywell unit. So, if you lose all oil pressure you'll still show 11 psi. What have others done to account for this?

f1rocket · #2 10-26-2015, 03:58 PM

Before you pull the pump, tap it on the top with a hammer. There may be a small particle stuck in the diaphragm. It's worth a try before draining the tank et al.

Jetguy · #3 10-26-2015, 05:35 PM

There was a post in January about a Honeywell replacement sender for $130. Check the last post on this thread for a part number. Might not work on a D180.

http://www.vansairforce.com/communit...ight=honeywell

rvbuilder2002 · #4 10-26-2015, 05:53 PM

Quote:

Originally Posted by rv3flier

Has anyone noted that the new Keller sender uses the bottom of its range of 4 ohms to show .75 BAR (about 11 psi) and not Zero like the old Honeywell unit. So, if you lose all oil pressure you'll still show 11 psi. What have others done to account for this?

I haven't done any work with this sensor but the low end resistance value shouldn't effect what the display indicates.
Each oil pressure sensor used with Skyview has its own associated mapping file.
If Dynon has done one for that sensor, what ever the sensor value is at zero, Skyview should be able to recognize that and display the value correctly.
It is very similar to the calibration process for the fuel level sensor, except that the values for the sensor are already established and are part of the sensor file.

rv3flier · #5 10-26-2015, 07:09 PM

Thanks F1Rocket, I'll give the hammer a try.

Jetguy, that unit is no longer offered by Lockwood, but thanks for the thought.

Rvbuilder2002, I called Dynon about the change, but was only told that they hadn't gotten any feedback on those that have the newer Keller sender. They thought it was just a drop in replacement. I wouldn't have even thought of it but there was a discussion on the Rotax forum from which I got my information. FWIW: http://joomla.rotax-owner.com/en/rot...art=0&start=20

Thanks for the follow up guys.

jlfernan · #6 10-27-2015, 06:14 AM

I replaced a friend's Honeywell sender with a Kavlico sender($85 at Aircraft Spruce). One hour job. worked perfect first time.

Infidel · #7 10-27-2015, 06:38 AM

I'd say chances are there is something else going on, like a ground, etc..

rv3flier · #8 10-27-2015, 08:52 AM

From Dynon EMS pressure sensor documentation addendum Revision B July, 2012, Flight DEK-180 will not display zero when connected to a Kavilco (and I assume the Keller) oil pressure sender. Instead they will read the minimum measurable pressure which is 12 psi with a 150 psi sensor. Given the difference in price and no need to use an adapter (1/8" NPT to 10 x1.0 mm) for the Keller, the Kavlico at $87 looks to be a good alternative.

It looks like the Kavlico is a three wire, +5vdc, sense wire, and ground, will require two additional connections to the EMS.

Thanks for the tip, jlfernan. I seem to remember something about a 100 ohm resistor off of pin 6 -- if so, did that require removal?

rv3flier · #9 10-27-2015, 05:26 PM

F1rocket, You're the man! If all else fails, get a hammer. It worked! Thanks for the tip.

John

RFSchaller · #10 10-27-2015, 08:24 PM

Harrumph! We engineers refer to this as mechanical agitation!😜

Gotta tell a sea story: I was a junior officer on a nuke sub in the 70's eager to absorb all the info I could. The tech manual on the reactor core said the control rod blades were rattling in their guide channels so "mechanical bias" was applied. -- They bent the blades so they contacted the guide channels. "Mechanical bias" has remained my favorite engineering euphemism!