Recently purchased an RV-8A and it has 60 hours on it. During recent flight the Tach read very high at 2700 rpm when it should read 2100 rpm. Also amp meter reads very low after start-up but after 2 minutes amps do climb into normal range. Plane performs and sounds as it normally does. Plane has "Light Speed Plasma II" electronic ignition and "Advanced Flight System" guage panel.
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Tach erroneous readings and amps read low
- Thread starter Oscar
- Start date
Carl Froehlich
Well Known Member
Many years ago I found the Lightspeed Plasma II+ to have a problem feeding the tach input on a Grand Rapids EMS setup. It seems the Plasma II+ firing pulse signal is so narrow the signal to the EMS gets caught up in noise.
The good folks at Grand Rapids offered a mod to the EMS circuit board that I did in the field - fixed the problem.
You might try discussing with the Advance team, perhaps they already have a fix as well.
Carl
The good folks at Grand Rapids offered a mod to the EMS circuit board that I did in the field - fixed the problem.
You might try discussing with the Advance team, perhaps they already have a fix as well.
Carl
Ralph Inkster
Well Known Member
As you are getting used to flying the new bird, now you get to learn its systems and how they were put together. First thing you will discover is that each experimental plane is unique in their build and systems. Hopefully you received schematics, builder notes, and component manuals with the purchase.
For the Amp meter readings, the first thing you should check is how and where the sender (shunt) was installed. There are 3 different ways to install these and gauge indications will be dramatically different for each. Check your installation manuals for this.
Tach issue might be as Carl described (& is common issue), but it could also be an instrument set-up issue. Check the Advanced installation manual for proper settings for your engine & ignition pulses.
Good luck & good flying your new bird
For the Amp meter readings, the first thing you should check is how and where the sender (shunt) was installed. There are 3 different ways to install these and gauge indications will be dramatically different for each. Check your installation manuals for this.
Tach issue might be as Carl described (& is common issue), but it could also be an instrument set-up issue. Check the Advanced installation manual for proper settings for your engine & ignition pulses.
Good luck & good flying your new bird
