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Discussion Starter #1
Hey all,

I'm trying to diagnose a cylinder misfire and I've taken the coil out from the bad cylinder and measured it's resistance, and it reads 0.5ohms on the primary and 65K ohms at the spark plug end. This seems reasonable to me though I haven't measured an assumed good ones spark plug end yet. However, I did measure an assumed good coil's primary side and it was also 0.5ohms so that checks out.

So I measured the ionic sensor output pin on the assumed bad coil (top one) and it was ~65K (coincidentally) ohms, however the assumed good coil (still installed) measured very high impedance on this pin (meter was over limit).

Does anyone know what the ionic sensor output pin on the coil is supposed to read resistance-wise? I measured it multiple times to make sure I had a good measurement.

Also, for clarification, I think that cylinder 1-5 are on the passenger side and 6-10 are on the driver side, with 1 and 6 being at the front of the car. Is this correct?

The car indicated cylinder 9 has the misfire.

Thanks,
Dave
 

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Correct on the cylinder and bank identification. Swap your ionic sensors and see if the misfire goes to #4. It usually ends up being a bad ionic sensor.
 

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Discussion Starter #3
Thanks for the response.

I'll swap the modules and see.

Do you know if the top pin on the ignition coil is used by the ionic module? If not what is the top pin on the ignition coil's 3-pin connector for?

This is where I measured a difference impedance than another assumed good coil.

Regards,
Dave
 

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No I don't, I'm not sure. The first step with a misfire is to swap the sensors to see if the misfire moves and it's free. Some start buying coils and spark plugs to only find out later it was the ionic sensor.
 

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Discussion Starter #6
Oh yes I forgot one more thing:

If I replace the ionic module and have to drive the car to the dealership to code it, does it hurt the ionic module or the car to drive it there without it being coded?

Thanks,
Dave
 

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I don't think any coding has to be done when an ionic module is replaced. Plug a new one in and you're good to go.
 
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