Twin spark engines

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If one of the cylinders two coil packs fail, there won't be a misfire necessarily...how would this show on diagnostic?
The vehicle in question is a Honda Jazz (07).....one coil pack disconnected, yet the management light didn't come on.
Any comments please?
Cheers and good evening
John :)
 
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Don't know for sure. I had a twinspark Alfa once, but that only really had one coil pack per cylinder - it just fired 2 plugs.

I think misfire detection on many modern cars is done by measuring crank speed fluctuations. If you have one coil pack per plug, I guess it was firing well enough on the remaining one for it not to log a fault code? Just a guess! With only one plug working, the emissions might get a tiny bit worse, so maybe it would be an emissions event that triggered the light - if it was going to?
 
I know on VAG cars the ECU monitors the voltage to each coil pack so it can detect if one fails or shorts out. On a twin spark it might just log the fault but not light up the engine management light. It depends if the engine is capable of working perfectly well with just one.
 
Are you sure the light's coming on at all, i.e. at ignition? And are there two (emissions and engine management)? Check the handbook!

Since the introduction of LEDs instead of bulbs in dashboards, black PVC tape has become the secondhand car dealer's new best friend :)
 
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You would think the knock sensor would pick up on the difference. May not log straight away.

I wonder does the engine sound different when you reconnect

isn't technology wonderful
 
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