Dwell Ignition Coil Xu7Jp4/xu10J4R

[megavolt0 0]

Hi guys! Does any know stock dwell of stock ignition coil xu7jp4/xu10j4r?

It's fine work on 3.3ms, but i have some problems on cold start. (-10C and below)

It's wasted spark coil.

[RossD 44]

3.3ms will be fine for a normal running, but when cranking at -10C I suspect that you will have quite a voltage drop. Do you have the option to change the dwell against battery voltage? If so, 5 or 6ms may be required at cranking speeds if the battery voltage is dropping below 10v.

 

Best way would be to measure using an oscilloscope and current clamp and find the dwell time when the current levels off on the coil input.

 

The other thing to check is the cold start enrichment, I would suspect this is incorrect if you have issues when cold starting before pointing the finger at the coil

Edited December 14, 2016 by RossD

[petert 586]

It can take over a week to get cold start perfect, as you really only get one go at it each day.