RE: Dynon Oil Temp erratic

fstringham7a · #1 08-01-2009, 08:38 PM

Phase one continues for my RV7A......A few squacks to overcome....none too serious.

The Dynon EMS D-120 Oil Temp has been real erratic. Swings plus or minus 20 degrees around 200 degrees F. All CHTs around 350.....

It appears that I may have a ground problem. The oil temp sender body is grounded to the engine case and according to Dynon that if there isn't some "magical / perfect" (my terms) ground betwen the case and the battery the instrument will be erratic!!!!! On the Dynon forum one individual (with the same problem) used a GRTs oil temp probe with it's own ground wire and sender wire in place of the Dynon oil temp sender. He said is oil temp was rock solid using the GRTs probe.

Have any of you Dynon guru's had this problem and if so how did you fix it ( without rewireing your plane ) and did any of you use the GRTs probe????

Considering I am breaking in a new Titan ECi IOX-360 Oil Temp is important to watch as a rock solid # indicator.

Frank @ 1L8 and SGU ...RV7A... Phase 1

kiwipete · #2 08-02-2009, 05:10 AM

Frank

I had a similiar thing last week. After 100 hours I started to get a fluaction in the oil temp. After checking I found a loose terminal. Now it's rock solid again.
(Dynon DEK180) my earth goes from firewall to accessory case.

Peter

fstringham7a · #3 08-02-2009, 06:39 AM

Quote:

Originally Posted by kiwipete

Frank

I had a similiar thing last week. After 100 hours I started to get a fluaction in the oil temp. After checking I found a loose terminal. Now it's rock solid again.
(Dynon DEK180) my earth goes from firewall to accessory case.

Peter

I found the same thing so I tightened it up...but no joy!!!!
I did read a post (Dynon Forum) where the feed wire fastener at the sensor was scuffed up. He reported good luck...I will try this next....

Frank @ 1L8 and SGU ...RV7A... Phase 1

kiwipete · #4 08-02-2009, 07:04 AM

Frank

In my case it was a poor crimp on the terminal.

Peter

jthocker · #5 08-02-2009, 07:36 AM

Seen this problem 3 times in the last year. It is your ground connection.
Check your crimps on the large cables, I had a loose one. I also moved the engine cable from the sump to the accessory case. Sand your firewall, sand the engine case(remove paint), sand your cable ends, all to ensure good contact, and your trouble will disappear.
Regards,

breister · #6 08-02-2009, 03:37 PM

Also, can be a bad ground between your engine block and the avionics bus. Tracked that one for weeks.

Ron B. · #7 08-03-2009, 02:55 PM

I soldered a ground wire to a SS hose clamp and clamped it to the tubing below the transducer. My thought was that the sealant used to seal the transducer was insulating the grounding. Worked great for me.
Ron

Andy Hill · #8 08-03-2009, 03:27 PM

GRT probe worked for us... $20 (?) and earthed to the fuselage - works fine.

Diagnosis - try turning off the Alternator and see if the fluctuations go away - they did for us. Indicates some sort of Earth issue, but GTT / $20 solved it

Andy & Ellie Hill
RV-8 G-HILZ

breister · #9 08-04-2009, 09:53 AM

Quote:

Originally Posted by Andy Hill

GRT probe worked for us... $20 (?) and earthed to the fuselage - works fine.

Diagnosis - try turning off the Alternator and see if the fluctuations go away - they did for us. Indicates some sort of Earth issue, but GTT / $20 solved it

Andy & Ellie Hill
RV-8 G-HILZ

Yep - turn off the alternator. If it is reading high or fluctuating normally but turning off the alternator "fixes" it, then it is a ground problem.