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Chris,
If you have thermocouple wire all the way,
I wouldn’t change it out. The thermocouples used in the EM-2 need
to be grounded. Are they?
Could you have a loose connection in the tach
wire? Does the engine change any when this happens or is it just a
readout change?
Have you changed the MP that the staging
change occurs? If not, try it and see what happens. You can always
set it back.
Tracy is back now… :>)
Bill B
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of Chris Barber
Sent: Tuesday, October 26, 2010
1:19 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Oil
pressure change...wow (and other stuff)
Sorry about the convoluted message.
Actually, I think I
was describing only two additional problems. Both have
been mentioned here and so far no joy on a fix. The first one
is that at around 6000 rpm, my EM2 tach cuts out and drops to a reading
of zero (sometimes it flashes 3000ish is as its going to zero).
Should I back it off to around 5800 rpm I can slowly advance the throttle and
get the tach to not cut out to about 6300 rpm, however, any power reading
over about 6300 and the tach reading drops back to zero until I retard the
throttle a bit.
Before Tracy left for Co he emailed that I try
adding a 5-6000 resistor in the tach wire with a capacitor to
ground. I did so, with various resistor wattage to no avail.
Either the behavior did not change or it showed zero all the time with the
higher wattage resistors. Not unexpected if I understand the
resistor thing. It was during my failed attempts to resolve the tach
issue when I noticed the original oil pressure drop.
The second issue mentioned is that
my EGT readings, which were originally working, started jumping all
around, reading from a couple hundred degree's to obscenely high
readings such as 6000/7000/8000 degrees. It is happening with
both EGT sensors. I have checked the sensors, the connections midway
through the wire run as well as into the back of the EM2. The wires
are thermal couple from the engine to the monitor. I am about to
replace the thermal coupling form the mid point to the monitor with
standard wire to see if that makes a difference. Absolute precession is
not my goal here, but consistence with be nice. Right now, it is
really annoying since it keeps setting off my alert light and keeps
flashing on the EMS. This sucks since I
have become conditioned to ignoring the alerts. I have considered
asking how to disable the readings until I figure out more.
A third issue I did not mention is my
staging star is staying on all the time, even though it seems obvious it
is running on all four injectors. Obvious as when I cut primary
injectors or secondary's, the engine keeps running along after a bit a
of stumble to get its bearings. Just started noticing that.
I will try to record the pressure
readings if it occurs to me when I am out there later today. Should allow
me better comparison.
From: Rotary
motors in aircraft [flyrotary@lancaironline.net] on behalf of
Bill Bradburry [bbradburry@bellsouth.net]
Sent: Tuesday, October 26, 2010
11:30 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Oil
pressure change...wow (and other stuff)
Chris,
The oil pressure spec for the Renesis is
51 lbs at 3000 rpm with an oil temp of 100 C. I imagine that it should be
close to the same for your engine as well. My guess is that you are still
getting a low pressure indication. When I started mine the other day, I
noticed that I was reading 71 lbs at idle when the oil was cold. As the
engine warmed up and I increased the rpm, it stayed in the range of 60-70.
In your msg below, what does this mean?
. (on top of my RPM's cutting
out around 6000 rpm - can slowly inch it up to 6300, with power to spare- if I
go slowly, but cuts out at rpm over 6300 and change on the EM2 and
an EGT reading issue).
It seems that there are three problems
in that sentence on top of the one about the strobes???
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Chris Barber
Sent: Tuesday, October 26, 2010
9:51 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Oil pressure
change...wow (and other stuff)
Since my oil pressure was down a bit
following my pressure repair I decided to take heed or some of the
comments regarding one of the possible causes as presented here. It
seemed to be the easiest that I could try.
So, I shelled out the bucks for some
Royal Purple 50 (actually, 20/50 IIRC). Geezh, I thought the
30 weight and 40 weight was pricey at $8 and $10 a quart, this stuff
was $16.00 a quart. I drained about 2 to 3 quarts out of the pan and out
of the filter and replaced it with the 50 wieght. So, now it was a blend
of the 30 and the 50. I cranked up the engine and my oil pressure was up
by about 10-15 psi. WOW! I did not expect such a dramatic
increase. I had just run the engine earlier (before I went
and purched the oil). Before the change, my idle pressure
was around 28-30. After the change it was in the low 40's. The most
psi I was getting before the change was about 50-55 psi at 6300 rpm.
After the change it was at about 72 psi at 6300.
I let her idle for about ten minutes and
all seemed good. So, since my temps seemed good and steady now that Outside air
Temps were have now dipped down into the low 90 I decided to taxi around a
bit. Yep, I sometimes enjoy taxiing around in my very expensive
go-cart.
The engine was running sooooo
smooth and strong. I was feeling pretty damn good about it all.
Since I was moving around on the ramp where there was quite a bit
of traffic following this weekends big 'ol Wings Over Houston air show, I
reached down and switched on my nav/strobe lights. At the exact instant
of turning on the light (which, btw, are on my secondary alternator circuit)
the engine started faltering and wanting to stall out. WTF!!! I
switched to the B computer and things smoothed out. Back to A and had to
add throttle and mixture to keep it running and it was still rough. Back
to B to make it back to the hangar.
Once back at the hangar, I checked the
MAP table (RWS EM2, btw) and nothing seemed changed from earlier. Kinda
sounded like fuel was having trouble getting to the injectors. I would
think to look at the injectors first, but am not inclined to focus here too
much since the engien smoothed out when changed to the B computer.
Since both computers use the same systems, it seems to be isolated to the
primary computer. Please, correct what I am missing here. Since
my judgment was clouded with anger, I put everything back in th
hangar for the night. This good good bad good bad stuff is taxing
and discouraging. I feel I am so close, then this nonsense. (on top
of my RPM's cutting out around 6000 rpm - can slowly inch it up to 6300,
with power to spare- if I go slowly, but cuts out at rpm over 6300 and change
on the EM2 and an EGT reading issue). To quote Mork....."Heavy
sigh".
Trying to wrap my head around where to
start on this latest PITA gremlin. It had been running as close to
perfect as I could have imagined.
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