Occasional engine cut-out, code 41.

91 XJ, 4.0, standard tranny.

Every now and then my engine cuts out completely for a second, then comes back on. It's like the ignition was switched off then back on.
The check engine light usually comes on when this happens and sets code 41, which has something to do with the alternator.

It will do it five times in one day, then not for weeks, then once, then not for days, etc. Seems very random.

I don't know how an alternator problem could cut power to the engine like that, so I'm wondering about something more like an intermittant fault in the crank position sensor.

I would check the wiring harness for melted wires. I would also check the ground and of course the CPS connector.

I would also check all of the main electrical wires. I had an ugly split in the insulation on the positive wire that went to my alternator, water got in and corroded it. Made the whole electrical system flaky.

Well in the process of elimination I found a lot of little problems that needed fixed, but in the end it turned out I did in fact have a bad alternator. When pulled and tested the voltage danced all over from 10 volts up to 15. I've never seen an alternator do that, but I guess the voltage swings were confusing the computer and that was causing the power drop-outs.

It was $$$$, but I put in a 160 am alternator that is designed to put out 100+ amps at idle. Should be great for feeding my 8274.