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I'll take a stab at your questions,
Paul.
Ed Anderson
RV-6A N494BW Rotary
Powered
Matthews, NC
----- Original Message -----
Sent: Wednesday, April 28, 2004 10:25
PM
Subject: [FlyRotary] ECU wiring
> Hi, fellow rotary enthusiasts. My 13b is
running pretty well with my Micro
> Tech ECU. I keep thinking that
even though it's running OK, I might have
> something wired incorrectly,
or that could be improved upon. I know that
> most of you are using
Tracy's ECU, but since they both accomplish the same
> task, I thought I
could ask a couple of questions to compare my system to
> Tracy's.
>
The wiring schematic shows a red wire going from
the positive side of
> the battery, through a 30 amp fuse, and to one side
of the injectors. That
> would put power to the injectors at all times,
even if the ignition switch
> is in the OFF position. I understand
that the injectors, however will not
> fire until the ECU sends a ground
signal to the other wire on the injector.
> Is this common practice?
Does Tracy's system work in a similar manner?
The two fuel injection systems I have
employed (HALTECH and Tracy's EC2) both have power directly to the
inejctors. The injectors should not activate or consume any power unless
the ECU is operating - that is grounding one of the leads to each
injector. I do have a 30 amp circuit breaker in my injector power
line
I personally would not want that line
going through my ignition switch. There is pulsating voltage on that line
when the injectors are firing and running that wire around under your instrument
panel could increase the chances for electronic interference. Too many
circuits tied to the ignition switch is something I would also
avoid.
> The
schematic shows the red wires that go to the 4 Bosch coils goes
> through
the ignition switch first. That made sense to me.
That sounds reasonable to me as
well. Although in my case, the power to my Mazda
coils also goes through a CB and not through the ignition switch. Basically, my
ignition switch does one thing , it enables the starter button. My power
to my Ec2 is controlled by a toggle switch which also provides power to my
starter contactor - so both my keyed ignition switch (actually starter
enable switch) and my EC2 toggle must be on for the engine to be started by
pushing a starter button. A safety feature that makes three actions
necessary to engage the starter and start the engine and unlikely all three
would accidently be turned on.
Key switch on - enables starter
button
Toggle Swith on - power to EC2 and
starter contactor
Starter Button that
causes starter contactor to close and provide power to the
starter.
> I have a small terminal strip on the cold
side of the firewall that
> gets it's power straight from the ignition
switch, so I could easily swap
> the "constantly hot" wire that goes from
the positive side of my battery to
> the injectors, disconnect it and
attach it to the "ignition on" power strip
> so that the injectors only
get power with the ignition switch in the ON
> position.
>
Not sure if this really matters....I wasn't so
sure it would be good
> to have constant power going to the injectors from
the battery. However,
> that's how the heavy starter wire
is....Direct power to the starter from the
> positive side of the
battery.
If you put your injector power line
on your ignition switch you have probably more than doubled the current running
through it, so make certain the switch can handle it - I personally would not do
it. Not trusting any single switch (and I purchased the best I could find)
all of my critical systems have a power line to them that goes through a 30 amp
circuit breaker than is normally open - should a critical switch fail, I can
push in the CB bypassing those switches and insure continued power to my
critical circuits - I call it my "Live Man Switch" {:>). Did I mention I was
a bit Anal about redundancy??
> I sure
would appreciate any and all opinions on this. It does run OK
> as
is....I'm just wondering if there are any safety concerns, etc about
>
leaving power to one side of the injectors even when the plane is not
being
> used.
I would think not. You have a
fuse (I would have a CB but that's just my personal bias) that should any
injector wiring short to ground, it should blow and prevent any further
damage. Just consider the injectors as coils of wire (which they are
electrically) and then they are no different that any other wire you might have
power to continuously.
>
Thanks for everyone's attempt in clearing this up
for me. Paul
> Conner, 13b powered SQ2000 in Mobile, AL
>
Paul, there is one consideration that has occurred to
me. How is the Micro Tech EFI circuit triggered? When I used the
HALTECH, you had to have a trigger signal from the ignition system. I
initially had mine triggered off of my leading ignition coil. One day my
engine died (fortunately on the ground) and I found that the leading coil
had died. That puzzled me at first as I had the trailing coil which should
have kept things running, until I realized that when the leading coil died so
did my EFI trigger!!!! So no fuel was being injected!
After that I rigged a switch so I
could get a EFI triggering signal off either coil. Tracy's EC2 uses the
crank angle sensor which is about as reliable as a spinning hunk of magnet and a
stational pick up coil can be and of course either of his Controllers will
continue to trigger both ignition units.
Thats about all I can think
of.
Ed Anerson
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