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Ok since it ran well in those rpm ranges before, we can
assume its not related to your pumps, filters or fuel plumbing since the EC2
does not control those.
If you had the auto tune feature and are using a narrow
band O2 sensor, it could be leaning out at the higher rpm due to the Z shape of
the voltage curve. But, I think that would be too subtle.
If missing at higher rpm then its either fuel or
spark. The higher rpm mean higher manifold pressure and SAG is worst at
high manifold pressure - so if you changed your spark plugs and it got better, I
would bet on the SAG.
I guess another possibility (just guessing) is that your
third pair of injectors were not firing at higher rpm. Another guess, is
you never got around to retuning your fuel map at the higher rpm after the
snubber fix.
OK, I give up
Ed
----- Original Message -----
Sent: Friday, September 14, 2007 7:54
PM
Subject: [FlyRotary] One for the smart
guys
OK guys, here's one to think about.
Problem: Major mis-fire at 6600 - 7000 rpm. Engine runs great
up until it begins mis-firing. This is a 20B running an EC-2 that's been
updated with the latest s/w (as of 9/1/07). This includes the snubber
fix and a modification for the Renesis CAS. Before the snubber upgrade,
the engine ran good in the upper rpm range, but not in the
lower rpm range. After the snubber upgrade & Renesis CAS
modification, it ran great in the lower rpm range, but had a
serious mis-fire beginning around 3800 rpm. An attempt was
made to correct the mis-firing problem by installing a resistor/zener diode
circuit in the CAS lead (this strategy worked for another Renesis
flyer). This approach was partially successful, but only up to the mid
6K range.
Multiple phone calls to Tracy resulted in no fix. I think he's
hiding in Colorado so he won't have to take my calls. (I'm kidding, of
course.)
Finally, today (after months of struggling) I discovered what was causing
the problem. It now runs great up to 7300 rpm, verified by a full-power
run down the runway. Anyone want to guess as to what the problem turned
out to be?
Mark S.
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