erratic oit temp

[richardsmi]

Re: Erratic oil temp

I fly an RV12 in the UK. My first Honeywell failed completely ( zero reading) before the planes first flight. A new warranty replacement worked for about 18hrs until it kept giving me scores of low pressure alarms (over water to add to the excitement!). This too has been replaced under warranty, but it still can fluctuate +/- 10 psi! As the ammeter readings also fluctuate +/- I wonder if there can be a relationship here????
I have carefully checked all of my earthing connections and they are spot on.
I have asked the LAA's (UK's regulatory body, Light Aircraft Association) advice on mounting the Honeywell on the firewall as per discussion on VAF and do not yet have their view.

 

[robertc]

As info I was having variable oil temps +/- 10 degrees. I put a hose clamp with a spade on a #16 wire on the sensor body back to the frame and it improved to +/- 2 degrees. I installed the Westach 399S9 per Dynons note. It's now dead solid. This is on an RV-7 with a TMX O-360. The sensor is grounded/spliced through one of the EMS120 black wires that was already through the firewall. Took about 30 min. To install.
Thanks Dynon
Bob

 

[dorsal]

I have had an issue with erratic high oil temps and occasionally cht and oil pressure readings. This is on an ems d10a and a Rotax 912S. Once I realized the sensor is an NTC (negative temperature coefficient) device I was able to track the problem to case grounding the Dynon. I was reading 30 to 40 mV from the Dynon case to the aircraft central ground with the unit power up. Since adding a 14 gauge ground strap from the case all is stable and happily in the green. It is important to note with the Rotax sensor that a bad connection to the sensor or engine ground will cause artificially low readings not high.