lgwg Posted November 25, 2023 Report Share Posted November 25, 2023 Hello everyone, I have swapped my ignition coil from the stock coils to MSD K20 coils, my engine model is Mitsubishi 4G engine, but I still keep the ignition system as a waste spark instead of COP. However, my driving wheel signal is noisy while WOT after the upgrade. I believe it was caused by the MSD coils because, if I swap the MSD coils with my stock coil, the speed signal becomes normal. You could find the log as attached. Can anyone guide me on how to solve this problem? Could I add something to filter the noise from the MSD coils? Thank you. Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 25, 2023 Report Share Posted November 25, 2023 Are you sure it is related to ignition noise, it looks ok on the first WOT pull in your log and only gets noisy above 160kmh. It also appears only the driven wheel gets noisy but the non-driven doesnt. What sensors are being used? Quote Link to comment Share on other sites More sharing options...
lgwg Posted November 26, 2023 Author Report Share Posted November 26, 2023 16 hours ago, Adamw said: Are you sure it is related to ignition noise, it looks ok on the first WOT pull in your log and only gets noisy above 160kmh. It also appears only the driven wheel gets noisy but the non-driven doesnt. What sensors are being used? Hi Adamw, Thank you for your response. I have confirmed that the issue is likely caused by the MSD coil. I have attached log before replacement below. The signal for the driven wheels comes from the factory sensor, provided by the speed sensor on the gearbox. The signal for the non-driven wheels is extracted through a frequency reduction circuit from the ABS rear wheel sensor and then supplied to the ECU, so it is not subject to interference. I once saw in the factory manual troubleshooting section that if the factory speedometer behaves abnormally, it is recommended to check whether non-standard resistance spark plugs are used. Therefore, I speculate that the speed signal from the original car may be affected by the ignition system. Additionally, after replacing the MSD K20 Coils, this issue occurred immediately, and it returns to normal when reverting to the original factory coils. Thank you. Quote Link to comment Share on other sites More sharing options...
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