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  #1  
Old 04-27-2022, 07:29 PM
Pilotjim77 Pilotjim77 is offline
 
Join Date: Jun 2018
Location: CHESHIRE, MA
Posts: 249
Default GRT EIS: High RPM Readings

My RPM is reading around 10,000 at low power settings and close to 20,000 at high power settings on the ground. I have a fairly new GRT EIS 4000 and older Horizon WS displays. RV-6 with an 0-320. Any thoughts on the cause? Can this be a settings issue?
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Purchased July 2019: RV-6 0320 Whirlwind Ground Adjustable Prop

"We can porpoises?" -- Leo Farnsworth
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  #2  
Old 04-27-2022, 07:48 PM
jclark jclark is offline
 
Join Date: Jan 2005
Location: Columbia, SC
Posts: 903
Default

There is a pulse per revolution setting that **MIGHT** be the cause.

Take a look at the documentation about that. It is different depending upon mags versus some electronic ignitions.

What engine/ignition do you have and what values did you use?
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  #3  
Old 04-28-2022, 08:14 AM
Canadian_JOY Canadian_JOY is offline
 
Join Date: Aug 2007
Location: Ontario, Canada
Posts: 2,530
Default

Of critical importance to this discussion... You haven't provided any indication of how you are sourcing RPM data. Are you using a pickup that threads into the body of a magneto? Picking it up from the tach output of the P-Mag? This information is critical in troubleshooting.
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  #4  
Old 04-28-2022, 11:28 AM
Pilotjim77 Pilotjim77 is offline
 
Join Date: Jun 2018
Location: CHESHIRE, MA
Posts: 249
Default

Quote:
Originally Posted by jclark View Post
There is a pulse per revolution setting that **MIGHT** be the cause.

Take a look at the documentation about that. It is different depending upon mags versus some electronic ignitions.

What engine/ignition do you have and what values did you use?
Quote:
Originally Posted by Canadian_JOY View Post
Of critical importance to this discussion... You haven't provided any indication of how you are sourcing RPM data. Are you using a pickup that threads into the body of a magneto? Picking it up from the tach output of the P-Mag? This information is critical in troubleshooting.
Thank you for the replies. It is an 0-320 H2AD engine with the original magneto setup. I do not know exactly how RPM data is sourced as I did not install the panel. Also, I have gone through all the settings on the EIS but have not yet gone through the settings on the displays. Once I get to the display settings, maybe I will be able to resolve this. It just seems like such a high number.
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Purchased July 2019: RV-6 0320 Whirlwind Ground Adjustable Prop

"We can porpoises?" -- Leo Farnsworth
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  #5  
Old 04-28-2022, 11:53 AM
jclark jclark is offline
 
Join Date: Jan 2005
Location: Columbia, SC
Posts: 903
Default Another thing to check.

Quote:
Originally Posted by Pilotjim77 View Post
Thank you for the replies. It is an 0-320 H2AD engine with the original magneto setup. I do not know exactly how RPM data is sourced as I did not install the panel. Also, I have gone through all the settings on the EIS but have not yet gone through the settings on the displays. Once I get to the display settings, maybe I will be able to resolve this. It just seems like such a high number.
Looking at this a second time makes me think that your display might have a "decimal place"/'divide by 10" problem. Cannot remember off-hand and I cannot get to airport but check how these values are set to be DISPLAYED.
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  #6  
Old 04-28-2022, 01:30 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 8,219
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+1 on James’ post. I have this vague memory that if this data had a 4 letter name (‘tach’) it was assigned to decimal arithmetic, but a 3 letter name (‘RPM’) was assigned to integer arithmetic. Sure looks like you’re missing a decimal point, e.g., 1000 and 2000 rpm.
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  #7  
Old 04-28-2022, 01:37 PM
Taltruda Taltruda is offline
 
Join Date: Oct 2017
Location: Las Vegas, NV
Posts: 1,183
Default

Quote:
Originally Posted by Pilotjim77 View Post
My RPM is reading around 10,000 at low power settings and close to 20,000 at high power settings on the ground. I have a fairly new GRT EIS 4000 and older Horizon WS displays. RV-6 with an 0-320. Any thoughts on the cause? Can this be a settings issue?
Download the EIS 4000 manual. Pages 20 and 21 talk about tach signals. I wonder if your tach signal is set to the wrong value.
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  #8  
Old 04-29-2022, 12:36 PM
Pilotjim77 Pilotjim77 is offline
 
Join Date: Jun 2018
Location: CHESHIRE, MA
Posts: 249
Default

Quote:
Originally Posted by jclark View Post
There is a pulse per revolution setting that **MIGHT** be the cause.

Take a look at the documentation about that. It is different depending upon mags versus some electronic ignitions.

What engine/ignition do you have and what values did you use?
Quote:
Originally Posted by Taltruda View Post
Download the EIS 4000 manual. Pages 20 and 21 talk about tach signals. I wonder if your tach signal is set to the wrong value.
These posts sent me in the right direction. It turned out to be the Tach P/R setting in the EIS which was set at 20 for some reason. I reset it according to the table and it did the trick. Thank you very much for the helpful information.
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Purchased July 2019: RV-6 0320 Whirlwind Ground Adjustable Prop

"We can porpoises?" -- Leo Farnsworth
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