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Message
David, sounds like you on the trail of the problem,
HOWEVER, I would not stop yet. Here's my view of the problem. Yes,
the EC2 will draw some current if the power to the injectors are on, but it
should be on the order of milliamps. If you are using the Peak and Hold
(low impedance) injectors they require around 4 amps to unseat the pentle and
inject fuel. The high impedance injectors require around 2 amps. The
EC2 power requirements with the engine off is minimal - in the milliamp
range. I could be wrong, but to the best of my knowledge,
the EC2 should not be drawing enough current to unseat the injectors
unless the engine is running.
Your diagnoses appears reasonable except the EC2
just does not normally draw anywhere near sufficient current to unseat
the injectors. I can turn my injectors on - leaving the EC2 switch off -
there is an initial squirt of fuel due to the transit phenomena I mentioned, but
after that the injectors stay seated. Yes, the EC2 program light is on
showing the EC2 is drawing power through the injector power circuit the same as
yours.
However, your finding sounds significant. I
would not hesitate to query Tracy about what you have found, it does not sound
normal to me.
Ed
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
Sent: Sunday, February 29, 2004 2:59
AM
Subject: [FlyRotary] Re: 13B - No start
problem
Ed & Rusty,
thanks again for your replies. Today I went out to the hangar and solved
the issue, … it’s very strange. I started by applying an ohm meter
across the injector leads with the fuses removed. As we would expect
from my problem one lead (hot lead) would indicate no connection with ground
while the other showed some current flow, but not zero resistance with ground,
1.2 Kohms (or 0.2 Kohms if I reversed the polarity of the ohmmeter)….
(scratch head and look dumbfounded). The same with the other
injectors. Hmmmm.
On a hunch I went and
turned on the main power to the EC2 and re-tried the above experiment.
Low and behold, there was no longer any current to ground. (infinite
resistance both leads). The system would hold fuel pressure and all was
right in my little world. In other words, if there is power to only the
injectors the EC2 seems to need some current and will draw across the
injectors causing them to open. But if I applied power to the main EC2
power input, the EC2 had enough power to properly close the injector
circuits. I repeated the entire experiment to make sure I wasn’t seeing
things.
Now that I know how
things work, it wont be a problem…. But still I haven’t run the
engine… J (i.e. and sure
to be in dire straits again soon)
Thanks again for your
help.
I am also having
trouble picturing where I could have gone wrong in the wiring. It seems
unlikely to me that I could have grounded all 4 of the injector leads.
Your idea about testing with the main connector unplugged is a good place to
start. But assuming that checks out OK (no ground with the connector
unplugged), I really would have no idea what to do next. I can’t believe
that I would put all 4 injector leads in the wrong hole. BTW, I did not
install an injector disable switch.
Hi
David,
Ed's message is
great, and I won't try to add much to it.
I did just take a
look at the EC-2 plug again, and noticed that the primary injector wires
are pins 17 and 18, with a ground on 19. The
secondary wires are pins 35 and 36, with the ground on 37. These are
supposed to be larger wire than the rest, so they don't fit as well in the
plug. All it would take is a strand of wire between 18 and 19, or
between 36 and 37 to cause one injector to open up when you apply power.
I'm betting you'll find your problem in the connector.
Of course it also wouldn't be too hard to accidentally swap one of
the injector wires with one of the grounds, which might do it too.
Naturally, I would never make such a mistake (ahem...)
:-)
Good
luck,
Rusty (off to TIG
some stainless)
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