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checking spark

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Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Tue Jan 20, 2009 6:29 pm Post subject: checking spark

On Tue, January 20, 2009 5:48 pm, Peerenboom's wrote:

 	  Quote: 	
		   Other than ohm meter checks or the people at Lockwood have a tester of some sort I do

 not know of a recommended way.


	


Maybe I'm missing something here, but just using an ordinary timing light with or

without an inductive pickup about the easiest way to check spark. You don't have to

remove a plug and there is no risk of damaging the ignition primary side (low voltage

side) with a disconnected spark plug wire.



That's how I do it easily enough.



-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA

425.241.1618 Cell

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

CDE2fly(at)AOL.COM
Guest

Posted: Tue Jan 20, 2009 6:49 pm Post subject: checking spark

Paul - this sounds like a great idea.  So the procedure would be to  clamp the inductive pick-up to any of the plug wires (all plugs still in the  engine) and turn the engine with the starter/battery to see if the strobe on the  timing light flashes?



Inauguration '09:  Get complete coverage from the nation's capital.

  [quote][b]

Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Tue Jan 20, 2009 7:10 pm Post subject: checking spark

On Tue, January 20, 2009 6:48 pm, CDE2fly(at)aol.com wrote:

 	  Quote: 	
		   Paul - this sounds like a great idea.  So the procedure would be to  clamp

 the inductive pick-up to any of the plug wires (all plugs still in the  engine)

 and turn the engine with the starter/battery to see if the strobe on the

 timing light flashes?


	


Yes, that's perfect. Even if your timing light doesn't have an inductive pickup, it

only adds the step of removing the spark plug wire or possibly only the protective

cover and connecting the timing light. Mine is DC powered and the big wire on the

starter is pretty handy for the positive connector and connect the black to any good

ground on the engine.



These modern ignition systems make only minimal spark so I'm not surprised you can't

see it even in dim light. I can't even see it on my Ford F-150 with a plug out but the

timing light picks it up fine.



-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA

425.241.1618 Cell

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Wed Jan 21, 2009 5:24 pm Post subject: Re: checking spark

Hi guys. 

Just buy an AC power tester like the one pictured. It's about $12. Hold it up next to the wire and it will flash with regular flashes if you have a good wire and plug. If the wire is bad it won't flash or only once in a while.. It only has to be next to the wire it doesn't have to touch it. You can diagnose an entire wiring system in no time or find where a break in the plug wire is.

AC tester 1.JPG

Description:

AC power tester

Filesize:

1.23 MB

Viewed:

580 Time(s)

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Thu Jan 22, 2009 10:51 am Post subject: Re: checking spark

Checking the spark that way is a really good way to ruin your ignition modules very quickly.   There are at least several possibilities now:



Your Ignition is wired incorrectly, which would be good because the modules would nave been burnt out if they were not producing a spark.



You may not be seeing the spark that is there.



Or you may have burnt up your ignition modules by using a really bad and harmful test method, in which case you would see no spark.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Fri Jan 23, 2009 8:23 am Post subject: Re: checking spark

Hi Mike,



That is why I like using my tester. You do not disconnect anything. Just run the engine as normal and hold the tester by the wire. You can even move it along the length of wire and it will detect a break.

Just another diagnostic tool to toss in your bag.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

patreilly43(at)hotmail.co
Guest

Posted: Fri Jan 23, 2009 8:48 am Post subject: checking spark

Roger C OK C I am sold. I Googled up the Greenlee tester. Yours (thanks for the picture) is 50-1000 volts. Greenlee has 2 models C yours and a low voltage model for 12-90 volts. I would guess I want the low 12-90 volt model for our application. But C as I stated C yours is the high voltage model. Does it work on 12 volt ignition systems? They are less than $15 apiece. I guess the question is academic C might as well buy both at that price.



Pat Reilly

Mod 3 582 Rebuild

Rockford C IL





 	  Quote: 	
		   Subject: Re: checking spark

 From: ssadiver1(at)yahoo.com

 Date: Fri C 23 Jan 2009 08:23:09 -0800

 To: kitfox-list(at)matronics.com

 

 --> Kitfox-List message posted by: "Roger Lee" <ssadiver1(at)yahoo.com>

 

 Hi Mike C

 

 That is why I like using my tester. You do not disconnect anything. Just run the engine as normal and hold the tester by the wire. You can even move it along the length of wire and it will detect a break.

 Just another diagnostic tool to toss in your bag.

 

 --------

 Roger Lee

 Tucson C Az.

 Light Sport Repairman - Maintenance Rated

 Rotax Service Center

 520-574-1080

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=226364#226364

 

 

 

 

 

 

&gt======================
	


&gt============

 	  Quote:

CDE2fly(at)AOL.COM
Guest

Posted: Fri Jan 23, 2009 5:54 pm Post subject: checking spark

Mike - I checked the wiring for each ignition position and all is well on  that front.  I'm hoping for the "not seeing the spark" scenario as burned  module(s) would be a bummer for sure.

  

 There's a definite consensus that testing for ignition by grounding a plug  to the block can damage the modules...does anyone know why this  is the case?  Seems like the plug would not know if it's grounded to the  block externally of if it's screwed into the block?  Seems the same  electronically...

  

 I purchased a timing light tonight and plan to check for ignition  using this method tomorrow. 

 Know Your Numbers: Get tips and tools to help you improve your credit score.

  [quote][b]

Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Fri Jan 23, 2009 6:47 pm Post subject: checking spark

On Fri, January 23, 2009 5:53 pm, CDE2fly(at)aol.com wrote:

 	  Quote: 	
		   Mike - I checked the wiring for each ignition position and all is well on

 that front.  I'm hoping for the "not seeing the spark" scenario as burned

 module(s) would be a bummer for sure.


	


You've isolated it just slightly. It's either a wiring (or grounding) problem or the

ignition module is faulty.



 	  Quote: 	
		   There's a definite consensus that testing for ignition by grounding a plug

 to the block can damage the modules...does anyone know why this  is the case?


	


The idea is that with the plug loose, it'll have either no ground contact, poor

contact or variable contact. In an open circuit condition, the impedance is so high

that it is thought that high voltage spikes in the secondary (spark circuit) could

leak into the primary, damaging electronic components similar to the damage that can

be caused with static electricity.



What bothers me about this assumption is that would imply that a bad spark plug wire

(or one that is disconnected) could damage the electronics. That seems to me to be an

unacceptable flaw in design.



 	  Quote: 	
		   Seems like the plug would not know if it's grounded to the  block externally

 of if it's screwed into the block?  Seems the same  electronically...


	


True, but the assumption is that the spark plug laying on the engine may not be

grounded at all, or periodically as the engine bounces around while cranking it over.



 	  Quote: 	
		   I purchased a timing light tonight and plan to check for ignition  using this

 method tomorrow.


	


Unfortunately, this will just confirm spark or no spark. Not the holy grail of repair

diagnostics.



BTW, did you know that your ISP (AOL) is appending advertising to your outgoing e-mail?



 	  Quote: 	
		   **************Know Your Numbers: Get tips and tools to help you improve your

 credit score.

 (http://www.walletpop.com/credit/credit-reports?ncid=emlcntuswall00000002)




	


That would be instant cause for parting with that company to me. Or at least getting

e-mail from someone else. I don't think gmail appends ads. I see that hotmail has

them, not sure about yahoo mail either.



-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA

425.241.1618 Cell

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Sat Jan 24, 2009 2:16 am Post subject: Re: checking spark

 	  Paul A. Franz, P.E. wrote: 	
		  

What bothers me about this assumption is that would imply that a bad spark plug wire

(or one that is disconnected) could damage the electronics. That seems to me to be an

unacceptable flaw in design.



	




Yes, I have worried about the same thing, either a wire going bad, or even one just coming off the plug, that would be an expensive thing to have happen for such a minor problem.  I have heard of these modules going out more often than I like, seems the Italians don't make as good as ignition modules as the Japanese put in their cars  



For CDE2Fly,



If you had the plug against ground, and did not have an open circuit giving the high voltage nowhere to go, you are probably fine.  The plug does not know if its screwed into the cylinder or not.  The danger is when it just hangs there not touching ground.   I bet you just find something in the wiring not quite right.  Also remember, the 912-S has to spin pretty fast to generate a spark,  was your starter battery fully charged and turning the engine over at a good rate ??  Its not like an aircraft where it will spark as you turn the prop by hand.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

Fox5flyer
Guest

Posted: Sat Jan 24, 2009 5:17 am Post subject: Checking Spark

Paul, very good points and I couldn't agree more.  I've been messing with snowmobiles for many years and they've been using  electronic ignitions for a very long time.  Many times I've had to lay the  plug on the top of the head to check for spark and never have I fried a  module.  I'm pretty sure they're more robust than that.

  

 However, those modules are expensive and a very  good way to eliminate the possibility is to take a simple working spark plug,  pretty much any plug will do that is similar to the OEM, then using Mig/Tig or a  torch of some sort, ascetylene (or however its spelled) is good, weld/braze  to the body of the plug a piece of wire a couple feet long.  On the  other end of the wire crimp a good robust alligator clip.  Make a couple of  these (or a set if you wish) then when you need to check spark simply use these  plugs in place of your originals, plug the alligator clip to a good engine  ground then lay them anywhere you can see them and crank the engine.   They'll have a good ground so no fear of frying electronics and you can even  hold them in your hand, if you're brave enough.  There are variations of  this.  You can also completely eliminate the wire and weld the  alligator clip directly to the plug.  Whatever your imagination comes up  with will probably work.  Great to hang on your shop wall for when you need  them.

  

 If you don't have the resources or time to roll  your own, then go here:  http://tewarehouse.com/7-05931

  

 Deke Morisse

Mikado Michigan

S5/Subaru/CAP  402+ TT

"The aim of an argument or discussion should not be victory, but  progress."

- Joseph Joubert

 

 

 Paul scribbled:

 On Fri, January  23, 2009 5:53 pm, CDE2fly(at)aol.com (CDE2fly(at)aol.com) wrote:

 	  Quote: 	
		   Mike - I checked the wiring for  each ignition position and all is well on

 that front.  I'm hoping  for the "not seeing the spark" scenario as burned

 module(s) would be a  bummer for sure.


	


You've isolated it just slightly. It's either a wiring  (or grounding) problem or the

ignition module is faulty.



 	  Quote: 	
		   There's  a definite consensus that testing for ignition by grounding a plug

 to  the block can damage the modules...does anyone know why this  is the  case?


	


The idea is that with the plug loose, it'll have either no ground  contact, poor

contact or variable contact. In an open circuit condition, the  impedance is so high

that it is thought that high voltage spikes in the  secondary (spark circuit) could

leak into the primary, damaging electronic  components similar to the damage that can

be caused with static  electricity.



What bothers me about this assumption is that would imply  that a bad spark plug wire

(or one that is disconnected) could damage the  electronics. That seems to me to be an

unacceptable flaw in  design.



 	  Quote: 	
		   Seems like the plug would not know if it's grounded to  the  block externally

 of if it's screwed into the block?   Seems the same  electronically...


	


True, but the assumption is that  the spark plug laying on the engine may not be

grounded at all, or  periodically as the engine bounces around while cranking it over.



 	  Quote: 	
		   I  purchased a timing light tonight and plan to check for ignition  using  this

 method tomorrow.


	


Unfortunately, this will just confirm spark  or no spark. Not the holy grail of repair

diagnostics.



BTW, did you  know that your ISP (AOL) is appending advertising to your outgoing  e-mail?



 	  Quote: 	
		   **************Know Your Numbers: Get tips and tools to help  you improve your

 credit score.

 (http://www.walletpop.com/credit/credit-reports?ncid=emlcntuswall00000002)




	


That would be instant cause for  parting with that company to me. Or at least getting

e-mail from someone  else. I don't think gmail appends ads. I see that hotmail has

them, not sure  about yahoo mail either.



-- 

Paul A. Franz

Registration/Aircraft -  N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue  WA

425.241.1618 Cell



   [quote][b]

matronics(at)bob.brennan.
Guest

Posted: Sat Jan 24, 2009 6:44 am Post subject: checking spark

When I first got my Model 2 my CFI pointed out it had the wrong kind of

wires/plugs and on several pre-flights we found one had come off during a

previous flight. It became a part of my pre-flight to push down all wires

until I finally (after a few weeks) found a source for proper aircraft plugs

and wires.



My point is that I had several instances of flying with wires-off-plugs and

no damage to the ignition module.



Bob Brennan - N717GB

ELSA Repairman, inspection rated

1991 UK Model 2 ELSA Kitfox

Rotax 582 with 3 blade prop

Wrightsville Pa 

--

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sat Jan 24, 2009 5:41 pm Post subject: Re: checking spark

Hi Pat,



The tester you want is the 50-1000 volt. Spark plugs are high energy AC. Then when you aren't using it on the plane I'm sure you have some honey do's where it might come in handy. It will not work on 12 volt.

The modules don't go bad that often. They are over a $1,000 each. If you are only dropping approximately 300 rpm then it is a plug or wire. It is not the module. A bad module is about 800+ rpm. The plug wires can be replaced as they are only screwed into the plug boot and ignition coil. The tester I posted will pick out the bad wire or plug. Most of the time it is a bad connection at the plug boot or a bad ground wire up by the modules. Find the effected wire with the tester. Pull the plug boot and trim the wire back about 1/4"-3/8" and re-insert the wire into the boot and or change the plug. You can unplug the modules on top of the engine and swap them and see if the problem follows the module during a mag check or stays the same. This will help tell you, along with the plug wire testing where to start looking.

 Who ever is having the problem what is the rpm drop during the mag check? Depending on the rpm that you do a mag check at, the rpm drop will be between 60-100 rpm. You should not do a low rpm mag check because it is hard to see anything. 3200-3500 is where most do their checks. At about 3300-3400 rpm the drop is about 80 rpm. The higher the rpm, the higher and easier it is to see a good mag drop or feel engine roughness. Doing a mag check at too low an rpm is not helpful.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

ppeerenbo(at)charter.net
Guest

Posted: Sun Jan 25, 2009 10:11 am Post subject: checking spark

Most of the problems I have had with a 300rpm drop were traced to a spark 

plug cap. Two were the spring clip for the top of the plug. Check the fit of 

each plug. "If it don't click pitch"



Paul N102DG

Model IV 912UL



---

CDE2fly(at)AOL.COM
Guest

Posted: Sun Jan 25, 2009 6:57 pm Post subject: checking spark

Thanks to everyone offering advice on trouble  shooting my ignition concerns.  The engine is a new (never run)  912S.  An update on the trouble shooting efforts over the weekend are  as follows:

  

 1.  I purchased an inductive timing light to check spark to  each plug.  This worked GREAT!  Simply power the light by clipping  power and ground leads to the battery and clip the inductive pick-up on to each  plug wire one at a time, while cranking the engine.  If the light  strobes, there is voltage to the plug.  Really slick way to check for spark  without removing plugs.

  

 2.  Results of my testing showed that six of the eight plugs are  getting voltage.  The plugs at the top of cylinders 3 and 4 were  not.  These plugs are both wired to the same dual ignition coil.

  

 3.  Trying to isolate the problem, I swapped ignition unit plugs so  that unit "A" was driving circuit "B" and vice-versa.  This resulted in no  change...still no voltage to the top plugs in cylinders 3 and 4 but this  should  confirm that the ignition units are functioning properly (i.e., not  damaged) 

  

 4.  When I first installed the engine (going back a year or so),  I recall removing one of the magneto pick-ups as I wrestled to get the  engine on the ring mount (not necessary as it turns out!).  Thinking I may  not have reinstalled the pick up correctly, I removed the engine from the  airplane to access the pick ups and check the one I removed for proper  position (as well as the others) with a feeler gage.  The pick-ups  were in the correct location.  

  

 5.  This leads me to suspect that there is either a faulty magneto  pick-up or faulty coil.  Not sure if the coil was damaged from  spinning the engine w/out plugs grounded or not.  Since this is my  first 912S install, I purchased a video which suggested removing one plug  from each cylinder and cranking the engine with the starter to purge  air pockets from the oil system prior to first start (which I did).   Based on feedback from this forum, this is not advised.  

  

 If anyone has ideas to trouble shoot the ignition coil, please let me  know.

  

 Chris

 Kitfox 7 912S

  

  

  

  

 Know Your Numbers: Get tips and tools to help you improve your credit score.

  [quote][b]

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