PocketRocket
I'm New Here
Hi,
I'm encountering a problem with my electronic ignition that I'd
appreciate further opinion on. My RV6 has an O-320 with a Slik
magneto on the left drive and Electroair EIS on the right drive. The
EIS is an older model with the DIU and coils mounted together, and has been
successfully operated for 480 hours.
The problem is that each time I go to take off the engine misfires
when full power is applied. I am getting 2180 rpm static, and as the
plane accelerates at full power, after 10-15 seconds the engine
starts to misfire. The misfires occur at roughly 1-2 seconds
frequency and last for 200-700 milliseconds. There is never any
backfiring.
I've conducted one flight, and found that as soon as I eased the
climb and reduced power, the problem went away. I was able to fly at
2,600 rpm with no problems, and could not re-create the misfire
whilst airborne. Because there is no backfiring, I initially assumed
a problem with fuel supply. This has been eliminated, and I have been
testing the ignition system whilst static on the ground.
I connected an oscilloscope input to an ignition lead and the trace
gave large spikes at every 1/2 engine revolution as expected.
However, intermediate lower amplitude spikes were also observed at
2/3 to 3/4 of the main spike period. This occurrs throughout the full
rev range, including clean running.
I also tested the signal output from the magneto timing housing. It
was found to have irregular modulation and an irregular gap.
I don't know what signal the processsor unit can tolerate, but I
think that the irregular signal from the timing sensor may be the
issue. However, the manufacturer still suggests that the charge is
arcing out through either the leads or plugs.
One significant point is that when I turn off the EIS, the engine
runs perfectly on the single magneto. When the EIS is turned back on
and the misfire occurs, I would expect the magneto to continue firing
as normal. I think it probably is, but possibly there's no fuel left to burn
and the misfiring is caused by wrongly timed sparks from the EIS
igniting fuel in the cylinders before the mixture is compressed and
ignited by the magneto.
Am I missing something? Any thoughts would be much appreciated
Regards, James
RV6 G-JSRV
I'm encountering a problem with my electronic ignition that I'd
appreciate further opinion on. My RV6 has an O-320 with a Slik
magneto on the left drive and Electroair EIS on the right drive. The
EIS is an older model with the DIU and coils mounted together, and has been
successfully operated for 480 hours.
The problem is that each time I go to take off the engine misfires
when full power is applied. I am getting 2180 rpm static, and as the
plane accelerates at full power, after 10-15 seconds the engine
starts to misfire. The misfires occur at roughly 1-2 seconds
frequency and last for 200-700 milliseconds. There is never any
backfiring.
I've conducted one flight, and found that as soon as I eased the
climb and reduced power, the problem went away. I was able to fly at
2,600 rpm with no problems, and could not re-create the misfire
whilst airborne. Because there is no backfiring, I initially assumed
a problem with fuel supply. This has been eliminated, and I have been
testing the ignition system whilst static on the ground.
I connected an oscilloscope input to an ignition lead and the trace
gave large spikes at every 1/2 engine revolution as expected.
However, intermediate lower amplitude spikes were also observed at
2/3 to 3/4 of the main spike period. This occurrs throughout the full
rev range, including clean running.
I also tested the signal output from the magneto timing housing. It
was found to have irregular modulation and an irregular gap.
I don't know what signal the processsor unit can tolerate, but I
think that the irregular signal from the timing sensor may be the
issue. However, the manufacturer still suggests that the charge is
arcing out through either the leads or plugs.
One significant point is that when I turn off the EIS, the engine
runs perfectly on the single magneto. When the EIS is turned back on
and the misfire occurs, I would expect the magneto to continue firing
as normal. I think it probably is, but possibly there's no fuel left to burn
and the misfiring is caused by wrongly timed sparks from the EIS
igniting fuel in the cylinders before the mixture is compressed and
ignited by the magneto.
Am I missing something? Any thoughts would be much appreciated
Regards, James
RV6 G-JSRV