I had my first flight of my RV-4 today, the flying qualities were
such that it felt as if the plane took off and landed itself. The
engine was pretty rough- I it ran smoothly on the ground, but on
climb out and downwind it felt like it was cutting out about once
a second and there was popping from unburnt fuel blowing out the
exhaust.  Engine rpm was 5300 on the downwind, airspeed read 70
kts, which I don't believe. The prop is a catto 74 dia by 88
pitch. engine temps never got over 185 coolant, 180 oil. Nest
time I take my gps to check airspeed.

Here's what I  believe is going on- mixture is way too rich, so I
ran it on the ground and leaned it out quite a bit- seems to run
nice and smoothly now. It was 70 degrees today, the coolant would
get up to 190 when at full throttle on the ground, and was
getting 5500 rpm static, oil was lagging behind at around 175. As
soon as I throttled back, oil and coolant temps would start
trending downward immediately, so I think the cooling will not be
an issue.

Next nice day that I'm off work, I'll go out again, but planning
on staying within gliding distance of our 9100 foot runway for
the first 15 hours or so.

Brian Trubee
RV-4


Congrats.

Jay

IMHO it is time Tracy started looking at other engine parameters
when tuning the engine. I have always maintained having the
computer look at the EGT's is one option. Switching to a
mass air flow sensor instead of just intake manifold pressure
is another. A third is standardizing on measuring the
intake pressure in the apex seal oil injectors.

Speaking of that Brian where are you taping off the intake
manifold pressure?

Try taping the pressure in the apex
seal lube holes. We have some taps machined we sell for that
purpose for $20 each. If you are not happy with them and they do
not help your problem send them back I will refund your cash.

This is not a unique problem with Tracy's EFI.

The EFI in this race car has the same problem and
it is addressed by a large vacuum accumulator which is
the chunk of PVC pipe in this picture.

Paul Lamar


CDI ignition projects Paul. We need simplicity and reliability,
low cost is a secondary requirement.

C. Smith