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GRT EIS: High RPM Readings

Pilotjim77

Well Known Member
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?
 
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?
 
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.
 
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?

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.
 
Another thing to check.

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.
 
+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.
 
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.
 
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?

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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