Oil temperature and EDM830

[FastTex]

I'm a new Mooney owner and on the first few flights I noticed an indicated high temp on my JPI 830 (235F) during maneuvers and climb. The original analog gauge was on the right side of the scale but still on the green. The POH says 220F max on cruise (I was about 210F on cruise...). My A&P measured (not exactly but just to compare...) a difference of about 30F between the JPI (+30F) and the old gauge (-30F). Also, we did see the difference in probe locations: the JPI measures from the front cowling while the old gauge from behind the baffling near the firewall. Apparently that's how it is supposed to be installed.

How do you guys handles this? Does any of the two instruments need to be calibrated? Should they indicate the same oil temp?

Thanks!

Edited June 27, 2018 by FastTex

[smccray]

47 minutes ago, FastTex said:

I'm a new Mooney owner and on the first few flights I noticed an indicated high temp on my JPI 830 (235F) during maneuvers and climb. The original analog gauge was on the right side of the scale but still on the green. The POH says 220F max on cruise (I was about 210F on cruise...). My A&P measured (not exactly but just to compare...) a difference of about 30F between the JPI (+30F) and the old gauge (-30F). Also, we did see the difference in probe locations: the JPI measures from the front cowling while the old gauge from behind the baffling near the firewall. Apparently that's how it is supposed to be installed.

How do you guys handles this? Does any of the two instruments need to be calibrated? Should they indicate the same oil temp?

Thanks!

I assume you mean the high temp alarm is set at 235?  I would set the oil temp alarm at 210 and make a change if oil temp exceeds 210- enrichen if flying ROP, lean if you’re setup LOP. Open cowl flaps if equipped, and lower the nose/increase air speed.  

Check the oil cooler and make sure it’s clean  and unobstructed.

Consider uploading your engine monitor data to savvy.  They will run the data against other similar airframes so you can see where your engine compares to others. That may be part of the paid service but it’s worth it to me. 

[carusoam]

You have two oitT sensors...

They are probably not colocated....

You will want to know where each sensor is mounted to understand why it is reading what it is...

The most important one is the ship’s gauge location. This is where the calibration needs to be on. So that the yellow and green ranges and redline are accurate for safe operation of your engine....

Your mechanic can point out the sensors. You can find them... either way, a drawing of your oil system will help identify where the two sensors are in the flow of oil...

Some POHs have really good drawings of the engine’s oil system...

OilT sensors are most often thermistors... a temperature dependent resistor...

A JPI can use thermistors or thermocouples... make sure it knows what it is reading...

One question... do all the temperatures read the same before starting the engine? A subtle hint that everything is calibrated before things warm up...

PP thoughts only, not a mechanic.

Best regards,

-a-

[FastTex]

The JPI sensor is on the front of the engine (where it should be according to my A&P). The aircraft gauge is on the back (original spot). So they appear to be installed properly.

Yes, the alarm is set to 235F. I can change it to 210 but it doesn't change the high temp reading...I understand I will get alerted sooner and can make correction (cowls, speed, mixture, etc).

We started the engine cold and when the original gauge hit 100F the JPI was measuring about 129F. That's how we saw the difference.

Do other EDM830s behave the same? Do you have the same OilT  reading on both instruments?

[Guest]

The first thing I would do is to boil both probes in water to see what they show, you can add a candy thermometer to the mix as well.  On the IO360A3B6D engine(don’t know what you have) there is a plug located beside the OEM oil probe.  

I have removed this plug and drilled and tapped them for the JPI oil probe, this puts both probes in the same oil for greater accuracy.

Clarence

[smccray]

I found your other post that we’re talking about an F- Savvy combines Js and Fs for data analysis. I don’t have it in front of me, but I believe 235 is crazy high for your engine.  It is significantly above my old J- my normal oil temps were in the range of your factory sensor. I never noticed a wide spread between the factory and the JPI.

I would call JPI. They can be a little cranky, but I’m betting on a probe issue- either you need a new probe, or there’s something wrong with the way the probe is wired into the computer. 

[cbarry]

It’s sounds like you may have simply a wiring issue with the JPI sensor.  A bad connection/resistance can show itself through an abnormally high readout.

[FastTex]

13 hours ago, smccray said:

I found your other post that we’re talking about an F- Savvy combines Js and Fs for data analysis. I don’t have it in front of me, but I believe 235 is crazy high for your engine.  It is significantly above my old J- my normal oil temps were in the range of your factory sensor. I never noticed a wide spread between the factory and the JPI.

I would call JPI. They can be a little cranky, but I’m betting on a probe issue- either you need a new probe, or there’s something wrong with the way the probe is wired into the computer. 

Thanks all for the feedback. I think calling JPI and verify probe and wiring it's a good idea!