X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rc1-smtp.comporium.net ([208.104.2.18] verified) by logan.com (CommuniGate Pro SMTP 5.3.1) with ESMTP id 4084618 for flyrotary@lancaironline.net; Fri, 15 Jan 2010 22:26:27 -0500 Received-SPF: pass receiver=logan.com; client-ip=208.104.2.18; envelope-from=jewen@comporium.net Received: from rg5.comporium.net ([208.104.2.25]) by rc1-smtp.comporium.net ({6ef86d1c-fcb7-4b71-ab61-5707d6041926}) via TCP (outbound) with ESMTP id 20100116032548846 for ; Fri, 15 Jan 2010 22:25:48 -0500 X-RC-FROM: X-RC-RCPT: Received: from 67-197-214-136.ln.dyn.cm.comporium.net (HELO home01) ([67.197.214.136]) by rg5.comporium.net (MOS 3.10.7-GA FastPath queued) with SMTP id CDY74914; Fri, 15 Jan 2010 22:25:48 -0500 (EST) Message-ID: <001401ca965b$ba37f460$6405a8c0@home01> From: "Joe Ewen" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Alternator Filter Date: Fri, 15 Jan 2010 22:26:44 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0011_01CA9631.D14C8FA0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1933 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1933 This is a multi-part message in MIME format. ------=_NextPart_000_0011_01CA9631.D14C8FA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al, Thanks for your reply. I tried a few more things since my earlier post. = I put a relay in the alternator output line (controlled in parallel = with the field power, so I could start with the filter out of circuit. = Engine started fine, turned alt on (now with filter in circuit) and the = engine continued running, but same results as before, missing ignition = pulses. I am still perplexed and no plausible explanation why a filter = (read capacitor) would prevent starting. Since the filter did not cure = the miss, I moved on to try again to figure out how the spikes from the = alternator (normal or not, will scope my cars alt tomorrow to verify = what I am seeing is normal, I do not believe I have any blown diodes.) SO what is the underlying cause. Looking at this the last couple of = weeks (very limited time due to work and cold temps - 20F in SC is = really cold, thought that was why I left the north.) I was suspecting = that this alternator noise (spike) was inducing a current in the = injector lines that was back feeding into the EC2 and if the spike = occurred at the same time the EC2 was triggering, the ignition pulse = would be inhibited. I had verified, with a scope, at this point that = the miss was in fact a missing ignition pulse. So working under the assumption that the noise was back feeding into the = injector driver, I was considering construction an opto isolator to test = this theory. Then you comments prompted me to take another look at my = wiring. The injector lines are all twisted pair, shielded, shield = grounded one end, cross any power lines at a 90, no parallel runs closer = than 4". It all looked good. Then a light came on. The alternator = wiring ran along and was attached to the aluminum mounting fixture that = hold the secondary fuel rail. The steel (read transformer core = material) secondary fuel rail that is connected to the steel braided = fuel lines. One of the steel braided fuel lines that runs along the = same path as the fuel injector lines. So the enhanced theory is that = the fuel rail/lines were acting like a core in a transformer. The test was to disconnect the existing alternator line between the = connection at the starter and the alternator, and run a new line that = stayed well away from and steel fuel components. Jumping back into the = pilot seat which has never been more than 3' above the ground (3 1/2 = when on jacks), I flipped all the switches I have so may times before, = waited for the Pentium 4 to boot up. After the P4 booted, I started the = engine monitor, started comms with the EC2, primed 2 shots and hit the = start button. As usual (without filter) she (yes, she is short for the = Glass Mistress, don't tell my wife) fired right up. Now the moment of = truth, with fingers crossed I flipped on the alternator, unintentionally = holding my breath I waited for the first miss. The first miss came but = later than normal, at which time I realized the mixture was a bit rich, = leaned it a bit and continued to wait for that oh so familiar miss, and = continued to wait. Can you say purrrrrr. Still perplexed by the no start with filter installed, but that can wait = for another day. Thanks for your random thoughs, they encouraged me go = go back out into the cold to try a few more random thoughs, one of which = discovered the underlying problem. I am anxious to rerun in the AM to = make sure my results were not a fluke. Then I can return the Fluke = Scopemeter to the office. Sincerely, Joe ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Friday, January 15, 2010 7:33 PM Subject: [FlyRotary] Re: Alternator Filter Joe; Gees, that's a weird one. I assume from your note that problem is no ignition trigger pulse, and = that the injectors are firing. Have you determined where the signal is = being interrupted? Is the loss of signal from the CAS, or out of the = EC2? The capacitor grounded to the engine will be inducing some sort of = opposite signal to ground - maybe affecting the CAS? Just some WAG. I have no filter on the alternator output - never saw more than the = normal ripple there. Could a failed diode in the output converter be = making big spikes? Wait - even with alt off, no start? What's in the = 'alt filter' besides a capacitor? Is the filter in the circuit when you = run the external wire? Just a few random thoughts - I expect you know more than I about how = this stuff works. Al G -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Joe Ewen Sent: Friday, January 15, 2010 3:13 PM To: Rotary motors in aircraft Subject: [FlyRotary] Alternator Filter I have been having problems with my engine installation. Starts, runs = great - turn on the alternator and the engine starts to miss. Put a = scope on R1 ignition trigger lead and sure enough missing trigger = pulses. Turn alternator off no more missing pulses. Looked at the = alternator output with the scope and as expected saw some spikes. = Bought an aircraft spruce alternator filter. Ran the engine , worked = fine until it would not prime or run any more. That turned out to be a = defective store switch. Replaced the switch and back to normal. Here = is the part I do not yet understand. Engine runs fine, added alternator filter and can not even get a pop. = Take the filter off, starts fine. Filter back on (alt off), no joy. = Filter on (alt on), no joy. Filter off, runs fine. I can not imagine = how a filter capacitor is interfering with the ignition of the = controller. If anyone has any insight please feel to speak up. I have 2 wiring ducts: 1. quiet - signals such as to the PCM, ignition = firing leads, low voltage sensor, analog signals. 2. Noisy side, = battery cables, ignition power, injector power and signal (twisted pair = shielded (shield properly grounded.) Alternator connects to battery cable at the starter. If I run an = external wire between the alternator and the battery (outside the = airframe, long wire - engine in back, battery in front (canard)) = everything runs fine.) Aesthetically this might not be a good approach, = not to mention the aerodynamic impact. This problem has kicked my butt this week working on it in the cool = 20F evening air. Any insight is appreciated, especially why a capacitor = (which does not conduct DC) would render the EC2 controller inoperative = would be appreciated. Thanks, Joe ------=_NextPart_000_0011_01CA9631.D14C8FA0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Al,
 
Thanks for your reply.  I tried a = few more=20 things since my earlier post.  I put a relay in the alternator = output line=20 (controlled in parallel with the field power, so I could start with the = filter=20 out of circuit.  Engine started fine, turned alt on (now with = filter in=20 circuit) and the engine continued running, but same results as before, = missing=20 ignition pulses.  I am still perplexed and no plausible explanation = why a=20 filter (read capacitor) would prevent starting.  Since the filter = did not=20 cure the miss, I moved on to try again to figure out how the spikes from = the=20 alternator (normal or not, will scope my cars alt tomorrow to verify = what I am=20 seeing is normal, I do not believe I have any blown = diodes.)
 
SO what is the underlying cause.  = Looking at=20 this the last couple of weeks (very limited time due to work and cold = temps -=20 20F in SC is really cold, thought that was why I left the north.)  = I was=20 suspecting that this alternator noise (spike) was inducing a current in = the=20 injector lines that was back feeding into the EC2 and if the spike = occurred at=20 the same time the EC2 was triggering, the ignition pulse would be=20 inhibited.  I had verified, with a scope, at this point that the = miss was=20 in fact a missing ignition pulse.
 
So working under the assumption that = the noise was=20 back feeding into the injector driver, I was considering construction an = opto=20 isolator to test this theory.  Then you comments prompted me to = take=20 another look at my wiring.  The injector lines are all twisted = pair,=20 shielded, shield grounded one end, cross any power lines at a 90, no = parallel=20 runs closer than 4".  It all looked good.  Then a light came = on. =20 The alternator wiring ran along and was attached to the aluminum = mounting=20 fixture that hold the secondary fuel rail.  The steel (read=20 transformer core material) secondary fuel rail that is connected to = the=20 steel braided fuel lines.  One of the steel braided fuel lines that = runs=20 along the same path as the fuel injector lines.  So the enhanced = theory is=20 that the fuel rail/lines were acting like a core in a = transformer.
 
The test was to disconnect the existing = alternator=20 line between the connection at the starter and the alternator, and run a = new=20 line that stayed well away from and steel fuel = components.  Jumping=20 back into the pilot seat which has never been more than 3' above the = ground (3=20 1/2 when on jacks), I flipped all the switches I have so may times = before,=20 waited for the Pentium 4 to boot up.  After the P4 booted, I = started the=20 engine monitor, started comms with the EC2, primed 2 shots and hit the = start=20 button.  As usual (without filter) she (yes, she is short for the = Glass=20 Mistress, don't tell my wife) fired right up.  Now the moment of = truth,=20 with fingers crossed I flipped on the alternator, unintentionally = holding my=20 breath I waited for the first miss.  The first miss came but later = than=20 normal, at which time I realized the mixture was a bit rich, leaned it a = bit and=20 continued to wait for that oh so familiar miss, and continued to = wait.  Can=20 you say purrrrrr.
 
Still perplexed by the no start with = filter=20 installed, but that can wait for another day.  Thanks for your = random=20 thoughs, they encouraged me go go back out into the cold to try a few = more=20 random thoughs, one of which discovered the underlying problem.  I = am=20 anxious to rerun in the AM to make sure my results were not a = fluke. =20 Then I can return the Fluke Scopemeter to the office.
 
Sincerely,
Joe
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Friday, January 15, 2010 = 7:33=20 PM
Subject: [FlyRotary] Re: = Alternator=20 Filter

Joe;

Gees, = that=92s a=20 weird one.

I assume = from your=20 note that problem is no ignition trigger pulse, and that the injectors = are=20 firing.  Have you determined where the signal is being = interrupted? =20 Is the loss of signal from the CAS, or out = of the=20 EC2?  The capacitor grounded to the engine will be inducing some = sort of=20 opposite signal to ground =96 maybe affecting the CAS?  = Just some=20 WAG.

 

I have no = filter on=20 the alternator output =96 never saw more than the normal ripple there. = Could a=20 failed diode in the output converter be making big spikes? Wait =96 = even with=20 alt off, no start? What=92s in the =91alt filter=92 besides a = capacitor? Is the=20 filter in the circuit when you run the external = wire?

 

Just a = few random=20 thoughts =96 I expect you know more than I about how this stuff=20 works.

 

Al=20 G

 

-----Original=20 Message-----
From: = Rotary=20 motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Joe = Ewen
Sent: Friday, January 15, 2010 = 3:13=20 PM
To: Rotary = motors in=20 aircraft
Subject: = [FlyRotary]=20 Alternator Filter

 

I have been having = problems with=20 my engine installation.  Starts, runs great - turn on the = alternator and=20 the engine starts to miss.  Put a scope on R1 ignition trigger = lead and=20 sure enough missing trigger pulses.   Turn alternator off no = more=20 missing pulses.  Looked at the alternator output with the scope = and as=20 expected saw some spikes.  Bought an aircraft spruce alternator=20 filter.  Ran the engine , worked fine until it would not prime or = run any=20 more.  That turned out to be a defective store switch.  = Replaced the=20 switch and back to normal.  Here is the part I do not yet=20 understand.

 

Engine runs fine, added = alternator=20 filter and can not even get a pop.  Take the filter off, starts=20 fine.  Filter back on (alt off), no joy.  Filter on (alt = on), no=20 joy. Filter off, runs fine.  I can not imagine how a filter=20 capacitor is interfering with the ignition of the controller.  If = anyone=20 has any insight please feel to speak up.

 

I have 2 wiring ducts: = 1. quiet -=20 signals such as to the PCM, ignition firing leads, low voltage sensor, = analog=20 signals.  2. Noisy side, battery cables, ignition power, injector = power=20 and signal (twisted pair shielded (shield properly=20 grounded.)

 

Alternator connects to = battery=20 cable at the starter.  If I run an external wire between the = alternator=20 and the battery (outside the airframe, long wire - engine in back, = battery in=20 front (canard)) everything runs fine.) Aesthetically this might = not be a=20 good approach, not to mention the aerodynamic = impact.

 

This problem has kicked = my butt=20 this week working on it in the cool 20F evening air.  Any insight = is=20 appreciated, especially why a capacitor (which does not conduct DC) = would=20 render the EC2 controller inoperative would be=20 appreciated.

 

Thanks,

Joe

 

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