----- Original Message -----
Sent: Wednesday, April 28, 2004 10:12
PM
Subject: [FlyRotary] Re: ECU wiring
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
Hi, Ed....thanks so much for taking time to
answer all of my questions. I will stay with my present system
where the injectors go directly to the positive side of the battery thru a
fuse, which will now be switched to a circuit breaker. I have had a few
instances in flying military aircraft where the CB popped, and was
successfully reset to complete the mission. Hard to reset a fuse.
The MicroTech unit uses
the crank angle sensor. Also, there is one wire which connects to the
terminal on the lead coil, that if no spark is coming from the coil, it turns
off the fuel pumps. However, all 4 coils have this wire running from one
coil to the second, to the third, and then to the fourth, so if any one of the
coils is functioning, the fuel pump would still get signal to
run.
It is wonderful to
have a forum such as this, where I can learn from both the successes and
failures of other experimenters, and save both time and money. Thanks again
for being such a major part of this, Ed. Paul
Conner