Help setting cylinder numbers in JPI 830

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Pre-takeoff checklist
Joined
Nov 11, 2018
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108
Location
Dallas
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Monte92
Got the 830 all wired up in the experimental this weekend. I have a 6 cylinder engine… everything is reading perfect except the tach. I’m like 700 rpms high. I called JPI because I can’t find anywhere in the manual how to change this. I. Called JPI and was sitting in the plane in the hangar… ready to diagnose. The fellow said “ I clock out in 20 minutes, I’m not getting into this. Call tomorrow “. Can anybody tell me how to find this? I power up and hit both buttons. That takes me through a menu of things but nothing about cylinder numbers. Thanks all.
 
Here is an answer from my AI assistant (dunno if this helps):


Correcting RPM Readings on a JPI EDM 830
Step-by-Step Procedure

Check Sensor Connections

Ensure the RPM sensor is properly connected to the EDM 830 wiring harness. Refer to the installation manual for the correct pin assignments and wiring.

Enter Pilot Program Mode

With the engine off, hold both the "STEP" and "LF" (Lean Find) buttons simultaneously until "PROGRAM" appears on the display.

Adjust RPM Calibration

Tap the "STEP" button repeatedly until you reach the field related to RPM (often labeled as "HP-?Y" or similar).

Hold both buttons again to enter the RPM calibration setting.

If prompted, use the "LF" button to tweak the RPM reading by small increments (typically ±3 RPM). This allows you to fine-tune the displayed RPM to match your aircraft's actual tachometer reading.

Tap "STEP" to accept and save the change.

Special Programming for Cylinder Count

In some installations, you may need to set the correct number of pulses per revolution (RF value) based on your engine's cylinder count:

For a 4-cylinder engine, set RF = 8.

For a 6-cylinder engine, set RF = 12.

This is done in the "FAC LIM" programming section.

Verify and Test

After making adjustments, verify the RPM reading matches your aircraft’s mechanical tachometer during engine run-up.

If discrepancies persist, double-check wiring and sensor compatibility, especially for newer engines with different RPM sensor types.

Notes

Always perform calibration and adjustments on the ground with the engine off unless otherwise specified.

For persistent issues or unclear settings, consult the official JPI EDM 830 manual or contact JPI technical support for guidance.
 
EdFred said:
Wow. Great customer service. Hope I never any JPI in any future planes I may have.
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It was a bit annoying. I said “ is this something that take a long time?”

JPI- No. just quick programming.

Me- I’m sitting in the plane… have a second?

JPI- I’m not getting into this. I clock out in 20 minutes man.

Me- I thought if it was quick maybe we could just do it.

JPI- Refer to the pilots guide. Have a nice day… click.
 
455 Bravo Uniform said:
Read pages 52-56 of your manual.
Thanks !!! I wasn’t hittin both buttons on the “end” menu. I missed that step. Thank you very much.
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EdFred said:
Wow. Great customer service. Hope I never any JPI in any future planes I may have.
Click to expand...
Disappointing considering buying little parts and things the lady has been quite helpful to me.
 
It’s neither intuitive nor clear, but it’s buried in there. Glad to help.
 
I have a JPI 730 4 cyl config. I wasn't aware there was a fine tuning process. There is a pickup installed in one Mag, possibly a hall effect transistor, that sends pulses to the 730. It effectively counts rotation of the Mag shaft or a feature that triggers the pickup. The pulses are converted to RPM in the 730. Although it starts as an analog signal, it should be rather discreet in the way it counts. I'm puzzled how RPM could be slightly off as opposed to a multiple of 3/2 as described above where it's configured for a 4 cylinder instead of 6.
 
focal_plane said:
I have a JPI 730 4 cyl config. I wasn't aware there was a fine tuning process. There is a pickup installed in one Mag, possibly a hall effect transistor, that sends pulses to the 730. It effectively counts rotation of the Mag shaft or a feature that triggers the pickup. The pulses are converted to RPM in the 730. Although it starts as an analog signal, it should be rather discreet in the way it counts. I'm puzzled how RPM could be slightly off as opposed to a multiple of 3/2 as described above where it's configured for a 4 cylinder instead of 6.
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If the primary tach is off, then it’s 3/2 of a wrong number…
 
focal_plane said:
I understand an integral of 3/2. I don’t quite understand a few RPM adjustment up or down.
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Ok I see what you’re asking. There is no “fine tuning” adjustment of RPM reading on the 830. It’s either off big because the number of cylinders in the settings doesn’t match the actual number on the engine, or it’s on/accurate. (Maybe it can be slightly and inconsistently wrong if there is an intermittent electrical connection or issue with the sensor?)
 
I had never heard of fine tuning on these instruments either. Post 2 above gives a procedure to “fine tune” RPM. I see it’s some kind of AI thing and apparently not from JPI documentation.
 
Yes, you have to go into the config screens and set up everything. The thing has a not-quite-non-volatile memory. If your plane is unpowered for a substantial period, it will come up thinking it only has 4 cylinders (BTDT).
 
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