What causes a bad signal to one coil??

[stephenpence]

Here's the second problem with my '91 XP 150. The #4 cylinder plug was oil fouled, so in an attempt to fix that, I discovered that the signal to the #4 coil is faulty. I've swapped multiple coils with their respective plug wires into that spot, and the problem stays on the #4 cylinder regardless of the coil that?s in that position. (Also, the tachometer is working sporadically. I have seen no difference in the performance of the motor when it is working vs. when it is not, but it is maybe a symptom, so I figured I?d list it!) So, what would cause the signal to the coil to be wrong, off.. sporadic??

I?m not sure if the 3k RPM problem is completely tied to the cyl #4 problem. It seems to me that with 5 cylinders, the old girl should still be able to power up past 2500-3000 rpms.. but maybe I?m wrong in that assumption! (if someone has information about that.. let me know!!)

 

[multimech]

Re: What causes a bad signal to one coil??

Either a bad trigger or a bad powerpack. It could be that the wiring is causing the problem, either from the trigger or the powerpack. You need to find the solution, because running the engine on 5 cylinders will lug it and blow it.

 

[stephenpence]

Re: What causes a bad signal to one coil??

New vocabulary word for the day for me "trigger"! can you help me out on that? what is it?? where can i find it in my manual even?? thanks for the response!