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Hi Bill,
Another thing you might check.
I had a similer problem to yours in my fuel
injected Ford V6 BD-4 with Tracys EC2 and EM2. For about a year I was plagued,
while flying, with a brief miss with a jerk from the engine at random
times even hours apart. It would mostly happen at higher RPM's then cruise,
but sometimes at cruise. I checked everything I could think of.
My problem was that one or two of my ignition
wires (MSD's 8.5mm Super Conductor wire set,
brand new no less) had some intermittent connectors. I discovered this by
checking the resistance of each wire while working the connectors a little bit
to see if the resistance fluctuated excessively or even became an open circuit.
Once I fixed these intermittents my problem was solved.
I know how unsettleing this can be while flying. I
hope you find your problem.
Robert Bollinger
----- Original Message -----
Sent: Wednesday, January 09, 2013 8:38
AM
Subject: [FlyRotary] Re: Aeroquip hose
changed to hiccup
A problem that mimics a poorly wired VR sensor, but
-only happens occasionally,
-with various levels of "response"
-and is getting worse.
Bill, if you haven't done so already, I would suggest changing the wiring
to the VR sensor completely. It sounds to me like a textbook example of
the worst sort of electronic malfunction you can have…an intermittent open.
You'll never find it under normal test conditions, and it will manifest
at the most inopportune times. The only way to completely rule it out as
a failure scenario is to completely replace the circuit path.
On Jan 8, 2013, at 11:42 PM, Bill Bradburry wrote:
No, I have the 2.85
gearbox. I have the MT electric prop, so I fly WOT and use the prop to
govern the engine speed.
I have changed the
plugs with no effect. The mixture is fine when this is
happening. Fuel pressure also. I had an incident once on take
off like you describe where the plane was backfiring like crazy just after I
lifted off. I had the mixture too rich. I dialed it back and
everything smoothed out. This is different. It doesn’t really
backfire. It is a thump and it jerks the engine and plane. You
can hear and feel it. It seems to be a single thump and it has varying
degrees of violence. Some are just a little miss and some are so bad
it shakes everything. These are less frequent, but they are bad enough
that I don’t think they are good for the PSRU, prop, or engine
mount.
That is why I have
been bugging Tracy about the change for the EC-2.
I have my fingers crossed that this will fix it.
:>)
Bill
B
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