Visibly Reduced Spark Output From Smart Coil | AEM
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enauman
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Last seen: 5 years 8 months ago
Joined: 10/26/2014 - 17:49
Visibly Reduced Spark Output From Smart Coil

I designed a quadrature encoder based ignition system for a blown triumph lakes racer.  It outputs a 5V trigger signal to one of your Smart Coils.  The ignition is programmed for a variable advance curve from start to 2500 RPM.  After 2500 RPM, the advance is fixed (software programmable).  The dwell is a constant 5mS that has been verified with an oscilloscope over the entire operating range.  Then engine runs around 6800 rpm WFO.  So the max duty cycle is

(.005)(6800)/120 = 28.3% which is well within your recommended maximum of 40%.  Plug wire is an Accel 8.8 mm Silicone Plus Spiral Core RFI Suppression with a total measured resistance of 454 Ohms.  Plug is a brand new NGK B9HS (non-resistive).  Plug wire contacts and plug threads are lubricated with a good dialectric grease.  Gap is set at .032".  The primary Power to the coil goes directly to the battery.  The head ground wire is bolted to a cylinder fin within 3" of the plug.  Signal and signal ground from the ignition is carried by twisted shielded pair.  The 12V supply to the ignition goes directly to the battery.  There is no charging circuit on the engine.  It runs total loss from the lead acid battery.  The coil is in the free air stream away from the engine for maximum cooling.  The engine and battery have heavy copper braided ground straps connecting to a common ground point on the frame. My problem is that the spark, which used to be a real bright, now looks like the weak spark you would see on a lawn mower engine.  Barely visible outdoors in the sunlight.  Is it possible for a smart coil to fail in such a manner that it would have a reduced output or do they fail completely?  What are the common causes of smart coil failures?  Can you offer any insight to my problem?

Bkos90
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Last seen: 9 months 2 weeks ago
Joined: 09/27/2019 - 11:34
Just saw this post. I know

Just saw this post. I know its a bit late but did you ever figure out the issue? I have the same problem now

Bkos90
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Last seen: 9 months 2 weeks ago
Joined: 09/27/2019 - 11:34
Just saw this post. I know

Just saw this post. I know its a bit late but did you ever figure out the issue? I have the same problem now