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  #1  
Old 03-01-2021, 01:31 PM
n518jh n518jh is offline
 
Join Date: Jan 2015
Location: Sun City West, AZ
Posts: 46
Default Rotax 912ULS Ignition problem

The pain goes on! My 2010 RV12, #120330 has had a continuing ignition problem; and this Forum has been 'sort of' helpful , but the problem persists. This as far as I have got to date. Either the engine starts beautiful, or not at all. When it doesn't start, I take off the top cowling and jiggle wires around the ignition modules. Sometimes it starts beautifully. Sometimes not at all.

So, what wires connect both modules either to ground or to power? That seems to be the best guess at this time. The electrical diagram doesn't work for me so far. Any suggestions? Is there some 'starting' wiring that might affect both modules? This is a two year problem, and the plane has become a hanger queen! Mark
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  #2  
Old 03-01-2021, 02:55 PM
benfra benfra is offline
 
Join Date: May 2007
Location: ft MYERS, FL Based @KPGD
Posts: 35
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I have a RV 12 120989, I had numerous electrical connection problems day one! The Rotax started with the two switches off, I was turning the engine over to check oil . I also had a prob. with ignition not getting power, it was wiring connectors inside the two white connector blocks, the white ones closest to the ignition modules. All the connectors were over crimped, ie wires cut or under crimped. It was very hard to find the badly done connectors in the white connector blocks because when pulled on the wires felt secure but were not connected to the pins!! I was able to correct the problem , all works well now! There was serious quality control problems, I hope Vans has more over sight now, I was never to get an answer, because was it Rotax or Vans? No one will tell me who is responsible for the bad quality control. Hope this Helps Benfra
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  #3  
Old 03-02-2021, 12:32 AM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,303
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Quote:
Originally Posted by benfra View Post
I have a RV 12 120989, I had numerous electrical connection problems day one! The Rotax started with the two switches off, I was turning the engine over to check oil.
I hear what you are saying… but the Rotax 9-series engines will not produce spark when turning propellor slowly by hand even with ignition switches in the “on” position. Rotax uses Capacitive Discharge Ignition that is powered by coil windings on the back of the engine. Ignition is not powered by battery. Engine must be spinning ~ 500 RPM to generate enough voltage to power ignitions, thus making hand-starting the engine very difficult at best.

This is different than a magneto ignition system that often utilizes an impulse coupling to retard spark at slow cranking speed. The impulse coupling momentarily increases magneto rotation speed to generate spark when the spring-loaded coupling releases at the preset ATDC timing. This is what makes aircraft magneto ignition systems so dangerous when turning prop by hand. Magneto, even with no impulse coupling, when removed from engine will still produce spark if turned by hand.
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Jim Stricker
EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 642

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H
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  #4  
Old 03-02-2021, 04:32 AM
blythet blythet is offline
 
Join Date: Sep 2011
Location: selma, NC
Posts: 16
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When you say it doesn't start, are you saying the engine turns over via the starting motor but doesn't fire and continue to run or are you saying it doesn't turn over via the starter motor?
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  #5  
Old 03-02-2021, 06:18 AM
benfra benfra is offline
 
Join Date: May 2007
Location: ft MYERS, FL Based @KPGD
Posts: 35
Default Ignition

Refrence my post , the Rotax was turning over with starter with ignition switches off!! benfra

Last edited by benfra : 03-02-2021 at 06:36 AM.
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  #6  
Old 03-02-2021, 07:13 AM
jnmeade jnmeade is offline
 
Join Date: Mar 2013
Location: Iowa
Posts: 181
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Quote:
Originally Posted by n518jh View Post
Either the engine starts beautiful, or not at all. When it doesn't start, I take off the top cowling and jiggle wires around the ignition modules. Sometimes it starts beautifully. Sometimes not at all.

So, what wires connect both modules either to ground or to power?
I'm no expert but don't know of a common power wire that affects both sides. Rotax trouble shooting even included switching the red wire from one connector to the other to see if the problem moves.

Are you 100% positive that when your engine runs it is running on both modules? How do you prove that? If it is only running on one module in the first place, maybe you do not have a common wire problem.

I'm don't know of a common ground, but it might be worthwhile to clean the grounds from the wires that with eyes that are attached to the right intake manifold.

I infer from your comments that you've looked at 74.00.00 especially chapter 3 of the heavy maintenance manual.
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  #7  
Old 03-02-2021, 07:21 AM
jnmeade jnmeade is offline
 
Join Date: Mar 2013
Location: Iowa
Posts: 181
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Quote:
Originally Posted by benfra View Post
Refrence my post , the Rotax was turning over with starter with ignition switches off!! benfra
I'm assuming you have two toggle switches for the ignition p-leads and a separate pushbutton or rotary start switch?

The engine should turn over but not start if the ignition toggle switches are off and the starter is engaged.

If the engine starts with the ignition switches off, you have one or two open p-lead circuits.
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  #8  
Old 03-02-2021, 07:56 AM
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cactusman cactusman is offline
 
Join Date: Oct 2012
Posts: 441
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Quote:
Originally Posted by n518jh View Post
The pain goes on! My 2010 RV12, #120330 has had a continuing ignition problem; and this Forum has been 'sort of' helpful , but the problem persists. This as far as I have got to date. Either the engine starts beautiful, or not at all. When it doesn't start, I take off the top cowling and jiggle wires around the ignition modules. Sometimes it starts beautifully. Sometimes not at all.

So, what wires connect both modules either to ground or to power? That seems to be the best guess at this time. The electrical diagram doesn't work for me so far. Any suggestions? Is there some 'starting' wiring that might affect both modules? This is a two year problem, and the plane has become a hanger queen! Mark
Do your modules have a green or yellow stripe? Earlier ones had a problem if i recall.

I see you are up in Sun City. I don't have my plans or plane handy as I keep them up north but i might be able to swing by and help you out. Also there is a mechanic for SLSA RV-12s over at Glendale who might be able to advise as well.

As I recall the white connectors to the Ignition came pre-done I assume by Rotax as Van's wouldn't have anything to do with that part of things. We had to scalp one white wire and run it through the steel connector holding the ignitions on the the mount, and many of us added an extra ground wire on the left side of the engine to the attachment point of the original VR. Proper grounding was a continually discussion on here in the "old" days as I recall.

If you have the plans for the engine mounting/wiring section (40 something), you might want go thru those step by step on the wiring.

PM me if you would like to talk further.
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Last edited by cactusman : 03-02-2021 at 08:00 AM.
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  #9  
Old 03-02-2021, 08:36 AM
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cactusman cactusman is offline
 
Join Date: Oct 2012
Posts: 441
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Quote:
Originally Posted by MMiller View Post
From your previous posts you indicate you have the older “Teal Label” non soft start ignition modules. As others have advised, these have a history of failing in a way similar to what you are experiencing. Heating or cooling them may bring them back to life, (this is a diagnostic test, not a repair procedure.) Unfortunately with this failure mode there is no other simple way to definitively test them, other than swapping with known good modules.
Yeah Lockwood might be able to do something for him. Worth a call for sure. They might be able to get Rotax to cover some of it. They have had some success for me with 3 sets of carb floats.

Lockwood also did my 5 year carb rebuild last year - record turn around time and engine ran like new. Best part was I threw my old spark plugs in and they called me to discuss and ask if wanted the old plugs back...lol.

Nope just felt it was running a little lean and wanted to confirm it!
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RV12 Flying
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Last edited by cactusman : 03-02-2021 at 08:38 AM.
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  #10  
Old 03-02-2021, 08:57 AM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,303
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Lockwood, CPS, or LEAF may be able to furnish a "used" CDI for testing. A couple of years ago LEAF sent me a used CDI. Turned out problem was carbs so I returned CDI to LEAF. I don't know if generosity is still available.

For what its worth - I'm still running original green label CDI's with non-soft-start now @ TT=633
__________________
-
Jim Stricker
EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 642

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H

Last edited by Piper J3 : 03-02-2021 at 08:59 AM.
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