2006 Honda Fit - L13A i-DSI engine misfire around 3K - 4.5K RPM when driving

Good afternoon:

I would like some assistance in understanding what is taking place in the attached ignition waveforms taken at idle from coil number 4, bank 2, on a 2006 Honda Fit with a L13A (1.3L i-DSI) engine coil on plug (COP). The car misfires between 3,000 and 4,500 RPM while driving. This was the only COP with an abnormal-looking waveform.

Can someone explain what can cause the 'noise' at the end of the current waveform?

Are these waveforms at idle? If so, try posting the waveforms at a rapid snap throttle- see how they look then.

Yes, they were taken at idle. I will try to take the quick snap throttle tomorrow, God's willing.

bills4065 wrote:

Are these waveforms at idle? If so, try posting the waveforms at a rapid snap throttle- see how they look then

Please see the attached snap throttle images.

 

 

 

 

Hi, good night.
I added the snap throttle waveforms to the forum. Would you be able to help me analyse them, please?

Sometimes, the spark can track down between the outside of the spark plug and the spark plug boot,  arcing to the Nut/threads of the spark plug, outside the cylinder. Especially, during acceleration or snap-throttle. I would pull the coil and look inside the boot for "Carbon Tracking". Also, look at the spark plug porcelain for tracking.

 

Looks a bit like Tyler's cracked spark plug waveform from this week:
   
These images belong to Tyler, not me!
Hope he doesn't mind

Please keep us posted on findings. I am also thinking carbon tracking on cracked spark plug.
I did not see a good spark line at the snap throttle personally. 

Initially, when the misfiring began, I did a cylinder drop test using my test light, and spark was leaking along the coil boot (see image).

I changed the coil boots and the spark plugs, and the misfiring (bucking) stopped for a few weeks. Unfortunately, the misfiring (bucking) returned after about three weeks. I captured the waveforms, and I did another cylinder drop test, and spark was still leaking from the boots. Someone said that if the spark is strong, it is possible or normal to leak through the boot. Can anyone confirm if that statement is accurate?

Spark Leaking from boot
 

Images of the new boot
  

Images of the old boot with corrosion
       

Images of the old spark plugs
   

Did you use oem parts for replacement? Ignition parts I would only buy from the dealer. And even then it is possible to still get a bad part. That bag says that part was made in China. Keep us posted.

I would have changed that entire ignition coil assembly.
If it's easier for the spark to escape the side of the ignition coil, it's going to keep doing it.

I ordered 4 new Hitachi coil packs. When they arrive, I'll see how they perform and provide an update.

Good afternoon.
I'm providing an update. After changing the coil packs (COP) and the spark plugs, the waveform is much better at idle and during snap throttle. However, the misfires are still present at 3000 to 4500 RPM only while driving (not at WOT when accelerating).
I'm going to capture the crank signal waveform to see if there are any anomalies. I'll provide an update later on.