I replaced the rotor with the cap and they make it so the cap can only go on one way, on mine at least.

 

With key on, slowly turn the engine over by hand while probing the signal wires for the CkPS and CPS. You should see a 5.0 VDC signal.

 

If you are getting signals, the next thing to do is see if the signals are synced. CkPS (blue) and CPS (coil sync) should be doing this:



This we gotta figure out how you're gonna do...

 

dang an O-scope would be sweet to have!!!!
I wonder if my work will let me check one out to bring home hahaha

 

Is there a way to have 2 multimeters going at the same time and listen for the beeps or watch the voltages come and go to see if they're in sync? Would be harder that way, but it could help...

 

Never tried it, so IDK if you could "rough it in" that way. You'd have to do it while turning the crank by hand as otherwise the signals go by so fast the DVM would be measuring like a continuous 2 VDC even at idle.

An entry level Hantek like this one is only 90 bucks, so if you consider that vs feeding the parts cannon, could turn out to be a pretty good deal.

 

BTW do you have an FSM? This is 1997 so should closely cover yours:

https://cdn.xjjeeps.com/pdf/en-us/19...ice-manual.pdf

Check out page 8D-6. Also test throttle position sensor. Your spark and fuel testing suggest the CkPS/CPS sync (or perhaps a wire or connector is broken so the signals aren't getting to the PCM) is the culprit but if not...

 

As an aside, a cam/crank that is out of phase would look something like



https://www.jeepforum.com/forum/f19/...e-fix-3487474/

While all this looks pretty flashy, these examples are from COP ignitions (me and the above poster have 2000s). I think the coil sync works the same, they just took the sync out of the distributor in 2000.

 

I guess cause starting in 2000 there wasn't any distributor to put the coil sync into...

 

2000 uses one coil per pair of cylinders, and fires on both intake an exhaust also called "wasted spark". So the distributor sensor isn't needed to determine which stroke you're on.

 

And makes for an interesting waveform from the coil drivers:

 

so i decided to check fuel since i have gone through almost the entire ignition system, turns out my fuel pressure was very low🤦🏻‍♂️ doesn’t explain the yellow spark but i’ll see if it runs with a new fuel pump

 

You might want to have your battery checked instead of replacing the fuel pump. I found that my 99 when the battery is low would turn over slowly and then fire up only to die within seconds if I did not tease it with the throttle. Once it was running for a couple of minutes, the rpms was about 700 and the alternator was producing voltage it would stay running on its on. My theory is that it did not have enough voltage to operate the fuel pump properly at the correct pressure. If not why wouldn't it stay running without me feathering the throttle?

The reason my battery was drained was I had the hood up and the door open checking the fog lamp switch sometimes with the key on, as well.

It was able to boost off with a LiOn booster pack (about the size of a pack of cigs), but I will have the battery tested today. I am almost sure its time for a new one as this one is old and tired. A cold snap would send it down for good, I am afraid.

Good Luck and get her back on the road!

 

I have already raced the battery and the fuel pump didn’t fix the problem, it has fuel pressure now but still won’t start. The plugs are getting wet with fuel so i’m assuming it’s still a spark issue, but i don’t know what else to check. I checked the coil wire and it had 0.0 ohms, replaced the coil, distributor, and plugs and wires. Is it possible the pcm could cause a weak spark??

 

just got it running, turns out the fuel pump was the issue and i got the timing wrong when i did the new distributor