CHT/EGT fluctuations

exbo3388

New Member
Joined
Mar 23, 2005
Messages
23
HELP!!
I have installed a D180 into a RV8. I have been chasing egt/cht fluctuations since day one.
The problem appears to be in the charging system... turn the alternator off and the readings are stable.
With a freshly charged battery the readings are stable, but after several start attempts the readings begin to fluctuate. I have checked all grounds, wireing, etc. Yesterday I installed a noise filter inline with the dynon power input. This helped considerably, The egt/cht bars are steady, but the digital numbers still fluctuate, but only +-10 degrees or so - they used to go nearly full scale. Also, the CHT readings seem very low, usually under 300 degrees. Any help will be appreciated!! :-/
 

dynonsupport

Dynon Technical Support
Staff member
Joined
Mar 23, 2005
Messages
13,226
This sounds like a really crummy ground between your engine and the battery / airframe. The reason a uncharged battery causes this is that the current going from the alternator to the battery causes a big voltage differential between the engine and the EMS.

What kind of ground do you have between the alternator and your battery? Have you checked to make sure everything is clean, unpainted, and tight?
 
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