YJ cranks but does not get spark

[Jacope01]

My 95 YJ (4.0) has been sitting for a couple months now due to this issue.

I believe that I’m not getting power coming into the ignition coil with the key in the “On” position.

I’ve chased my tail up to this point. Lots of stuff has already been replaced.
Maybe I’m checking power into the coil incorrectly? Jeep will crank strong and almost turn over but no power (I assume) to the ignition coil means no spark which means no start.
Check all fuses in cab and in engine bay and they all seem good.
This is my first vehicle and I’m not super experienced with wiring so it’s been a struggle tracking down what is wrong.

Thanks!

 

[dodgerammit]

There are some basic trouble shooting videos on Youtube that should help walk you through some diagnosing procedures. Power addicts channel and jeep solid channel are two I recommend.

First, when you first turn the key (just a couple of clicks, but not cranking) do you see the Check engine light come on? That is the very first thing you should look for. that is the PCM self test light. If it doesn't illuminate, make sure the bulb is good. if it still doesn't illuminate, that is the sign of a failed PCM.

If it passes that, swap out some relays in the box under the hood. You need to swap your ASD (Auto shutdown) relay with horn or something insignificant to engine functions.

if it still doesn't start, listen to see if your fuel pump will turn on. Just turn the key a couple of clicks, but don't start motor. Listen for the little hum at the rear of the Jeep. Note, after a couple of starting attempts, it may not turn on since it will have primed. There will be youtube clips on how to bypass the relay to give it full time power to test. Power addicts channel.

If it comes on via bypassing relays, then do the relay swap again with the horn relay and the fuel pump relay. See if it fires or not.

If it passes those tests, but still doesn't start, look up fuel pump/fuel pressure testing on Jeep Solid channel again on how to check for fuel getting to throttle body.

Do those tests and report back.

I had an issue recently with mine dying during a drive, then not having fuel pressure at all to the fuel rail, but pump was turning on. Turned out the replacement pump/sender in the tank developed a split in the short rubber pick up tube.

There are other things (sensors) that can also cause non-starting issues. All in all, these things are pretty basic, so a good vehicle for you to 'cut your teeth' learning how to troubleshoot and do repairs on. Good luck!

 

[dodgerammit]

Also, if the computer self test passes, do the code check on the pcm as well. Jeep solid should also show how to do the obd 1 self test.