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0. 07:08 AM - Coming Soon - The List of Contributors - Please Make A Contribution Today! (Matt Dralle)
1. 01:05 AM - Engine monitor display scramble from EFI sense line EM2 from RWS (Todd Bartrim)
2. 05:24 AM - Re: Engine monitor display scramble from EFI sense line EM2 from RWS (Kent or Jackie Ashton)
3. 06:18 AM - Re: Engine monitor display scramble from EFI sense line EM2 from RWS (C&K)
4. 06:46 AM - Re: Engine monitor display scramble from EFI sense line EM2 fro (johnbright)
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| Subject: | Coming Soon - The List of Contributors - Please Make |
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Message 1
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| Subject: | Engine monitor display scramble from EFI sense line |
EM2 from RWS
I have an issue with my engine monitor display where the display will
scramble leaving me with a meaningless display as can be seen in the
attached picture
[image: EM2 display_scrambled.jpg]
The engine Monitor is from Real World Solutions and is the very early first
edition EM2 (serial #003). I also have an early edition EC2 (engine
ignition and injection controller).
RWS was Tracy Crooks company before he retired, and he still provides some
support when he can, however he also is enjoying his retirement offline so
is often hard to get a hold of,
so I thought I would pose the question here while awaiting a response so
maybe I won't even have to bother him.
So here are the details of the problem. The engine monitor has 36?
different parameters that it displays on 8 screens. There are 24 different
sensors (pressure, temperature, level) with the remaining being provided
through a serial data link from the EC2 along with an EFI sense which is
connected to the #1 primary injector output from the EC2. I've determined
that it's this last wire that is causing my grief.
This EFI sense is measured for it's pulse width in order to calculate a
surprisingly accurate fuel flow, RPM, HP, fuel remaining, MPG (for
efficiency). But the noise on this line seems to be the cause of the data
scrambling on the display. Simply pressing the cancel button (there are 4
user buttons to control display) will rest and clear the issue.
But here's the weird part. It seems to be related to relative humidity.
During hot dry, summer weather this display will rarely scramble, sometimes
going up to an hour without an issue. But on cooler humid days I would have
to reset it every few minutes which gets a little annoying. However right
now as we are not enjoying the cold November rains before winter will
arrive with cold dry weather, I'm finding that it is scrambling almost
immediately after a reset. This makes no sense to me, but I've observed
this pattern enough to be sort of certain that it is not a coincidence...
but I could be wrong.
In any event, it matters not whether it is or isn't triggered more by the
humidity, but what it did allow me to do is determine where the issue is
coming from as before it was too random to allow easy troubleshooting but
now as it is more consistent it was quite quick to narrow it down.
I've cut this line (which is shielded with only one end of the shield
grounded) and installed a connector. With it disconnected, the EM2 display
is rock steady (up to a 10 minute ground run) but with no RPM or any fuel,
power, or efficiency data. Connect the line and it immediately will
scramble. I estimate that the frequency of the injector pulse on this line
would only be at max about 100Hz at 6000 RPM. I've considered that a simple
low pass RF filter to ground may work as the frequency that I'm trying to
measure is well below what the filter would remove, but would it still have
an effect on the pulse width? which would be undesirable as that would
effect the signal driving the #1 primary injector.
I'm hoping that someone can suggest an easy fix so that I can implement
it when I get back up to the airport this weekend, other wise if more data
is needed to help find a solution I will take a scope up there and try to
get some more detailed data.
Right now our days are getting pretty short up north here so it's dark by
the time I get off work, so I'm restricted to weekends only. Thanks for any
help that can be provided.
Todd Bartrim
RV9 13Bturbo
Message 2
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| Subject: | Re: Engine monitor display scramble from EFI sense |
line EM2 from RWS
Just watching a video the other day about old solder joints that break or crack
due to hot/cold cycles or mechanical stress. They are difficult to detect with
the eye but I think I would try to touch as many of your joints as possible
with a small soldering iron.
-Kent
> On Nov 5, 2019, at 4:03 AM, Todd Bartrim <bartrim@gmail.com> wrote:
>
> I have an issue with my engine monitor display where the display will scramble
leaving me with a meaningless display as can be seen in the attached picture
> <EM2 display_scrambled.jpg>
> The engine Monitor is from Real World Solutions and is the very early first edition
EM2 (serial #003). I also have an early edition EC2 (engine ignition and
injection controller).
> RWS was Tracy Crooks company before he retired, and he still provides some support
when he can, however he also is enjoying his retirement offline so is often
hard to get a hold of,
> so I thought I would pose the question here while awaiting a response so maybe
I won't even have to bother him.
>
> So here are the details of the problem. The engine monitor has 36? different
parameters that it displays on 8 screens. There are 24 different sensors (pressure,
temperature, level) with the remaining being provided through a serial
data link from the EC2 along with an EFI sense which is connected to the #1 primary
injector output from the EC2. I've determined that it's this last wire
that is causing my grief.
> This EFI sense is measured for it's pulse width in order to calculate a surprisingly
accurate fuel flow, RPM, HP, fuel remaining, MPG (for efficiency). But
the noise on this line seems to be the cause of the data scrambling on the display.
Simply pressing the cancel button (there are 4 user buttons to control
display) will rest and clear the issue.
> But here's the weird part. It seems to be related to relative humidity. During
hot dry, summer weather this display will rarely scramble, sometimes going
up to an hour without an issue. But on cooler humid days I would have to reset
it every few minutes which gets a little annoying. However right now as we
are not enjoying the cold November rains before winter will arrive with cold dry
weather, I'm finding that it is scrambling almost immediately after a reset.
This makes no sense to me, but I've observed this pattern enough to be sort
of certain that it is not a coincidence... but I could be wrong.
> In any event, it matters not whether it is or isn't triggered more by the humidity,
but what it did allow me to do is determine where the issue is coming from
as before it was too random to allow easy troubleshooting but now as it is
more consistent it was quite quick to narrow it down.
> I've cut this line (which is shielded with only one end of the shield grounded)
and installed a connector. With it disconnected, the EM2 display is rock
steady (up to a 10 minute ground run) but with no RPM or any fuel, power, or efficiency
data. Connect the line and it immediately will scramble. I estimate
that the frequency of the injector pulse on this line would only be at max about
100Hz at 6000 RPM. I've considered that a simple low pass RF filter to ground
may work as the frequency that I'm trying to measure is well below what the
filter would remove, but would it still have an effect on the pulse width? which
would be undesirable as that would effect the signal driving the #1 primary
injector.
> I'm hoping that someone can suggest an easy fix so that I can implement it
when I get back up to the airport this weekend, other wise if more data is needed
to help find a solution I will take a scope up there and try to get some more
detailed data.
> Right now our days are getting pretty short up north here so it's dark by the
time I get off work, so I'm restricted to weekends only. Thanks for any help
that can be provided.
>
> Todd Bartrim
>
> RV9 13Bturbo
Message 3
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| Subject: | Re: Engine monitor display scramble from EFI sense |
line EM2 from RWS
Rather than adding filtering that was previously not needed I'd start by
confirming ground integrity. FIrst in external wiring and then for
circuit board solder joints. Then I test and usually replace any
electrolytic caps in the sensing circuit and power supply circuitry.
Selectively warming (drying) or cooling (freeze spray) the circuit board
components is a quick test that can help narrow things down. Eventually
I look at whether the input signal itself has changed but in my limited
experience that is more likely on ignition sensing than on an injector
sensing if the grounds are good. I have not worked on any RWS systems.
The good news is that now that you can immediately trigger the fault,
your chances of finding the problem are much improved. With analog
inputs I also like to clean the board with alcohol when humidity is
suspected but I doubt that is a problem with your digital pulse sending.
Ken
On 05/11/2019 4:03 AM, Todd Bartrim wrote:
> I have an issue with my engine monitor display where the display will
> scramble leaving me with a meaningless display as can be seen in the
> attached picture
> EM2 display_scrambled.jpg
> The engine Monitor is from Real World Solutions and is the very early
> first edition EM2 (serial #003). I also have an early edition EC2
> (engine ignition and injection controller).
> RWS was Tracy Crooks company before he retired, and he still provides
> some support when he can, however he also is enjoying his
> retirementoffline so is often hard to get a hold of,
> so I thought I would pose the question here while awaiting a response
> so maybe I won't even have to bother him.
>
> So here are the details of the problem. The engine monitor has 36?
> different parameters that it displays on 8 screens. There are 24
> different sensors (pressure, temperature, level) with the remaining
> being provided through a serial data link from the EC2 along with an
> EFI sense which is connected to the #1 primary injector output from
> the EC2. I've determined that it's this last wire that is causing my
> grief.
> This EFI sense is measured for it's pulse width in order to calculate
> a surprisingly accurate fuel flow, RPM, HP, fuel remaining, MPG (for
> efficiency). But the noise on this line seems to be the cause of the
> data scrambling on the display. Simply pressing the cancel button
> (there are 4 user buttons to control display) will rest and clear the
> issue.
> But here's the weird part. It seems to be related to relative
> humidity. During hot dry, summer weather this display will rarely
> scramble, sometimes going up to an hour without an issue. But on
> cooler humid days I would have to reset it every few minutes which
> gets a little annoying. However right now as we are not enjoying the
> cold November rains before winter will arrive with cold dry weather,
> I'm finding that it is scrambling almost immediately after a reset.
> This makes no sense to me, but I've observed this pattern enough to be
> sort of certain that it is not a coincidence... but I could be wrong.
> In any event, it matters not whether it is or isn't triggered more by
> the humidity, but what it did allow me to do is determine where the
> issue is coming from as before it was too random to allow easy
> troubleshooting but now as it is more consistent it was quite quick to
> narrow it down.
> I've cut this line (which is shielded with only one end of the
> shield grounded) and installed a connector. With it disconnected, the
> EM2 display is rock steady (up to a 10 minute ground run) but with no
> RPM or any fuel, power, or efficiency data. Connect the line and it
> immediately will scramble. I estimate that the frequency of the
> injector pulse on this line would only be at max about 100Hz at 6000
> RPM. I've considered that a simple low pass RF filter to ground may
> work as the frequency that I'm trying to measure is well below what
> the filter would remove, but would it still have an effect on the
> pulse width? which would be undesirable as that would effect the
> signal driving the #1 primary injector.
> I'm hoping that someone can suggest an easy fix so that I can
> implement it when I get back up to the airport this weekend, other
> wise if more data is needed to help find a solution I will take a
> scope up there and try to get some more detailed data.
> Right now our days are getting pretty short up north here so it's
> dark by the time I get off work, so I'm restricted to weekends only.
> Thanks for any help that can be provided.
>
> Todd Bartrim
>
> RV9 13Bturbo
Message 4
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| Subject: | Re: Engine monitor display scramble from EFI sense |
line EM2 fro
[quote="kjashton(at)vnet.net"]Just watching a video the other day about old solder
joints that break or crack due to hot/cold cycles or mechanical stress. They
are difficult to detect with the eye but I think I would try to touch as many
of your joints as possible with a small soldering iron.
-Kent
I had this happen on an automotive dashboard mounted environmental control that
worked intermittently. The circuit board had a control side and a power side.
Some of the power side solder joints looked like this photo. I had a theory it
happened on the power side due to greater thermal excursions perhaps in combination
with other factors. Remelting fixed it.
--------
John Bright, RV-6A, at FWF
O-360, dual SDSEFI EM-5-F
https://drive.google.com/drive/folders/1u6GeZo6pmBWsKykLNVQMvu4o1VEVyP4K
Newport News, Va
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=492376#492376
Attachments:
http://forums.matronics.com//files/broken_solder_circuit_board_thru_pins_190.jpg
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