Yesterday, I was minding my own business in the slow lane, had the top that covers just the front two seats on, music crankin' weather was perfect, not too hot, not too cold. I was going to take a different path home, just to cruise on more backroads than highway... and then it happened!
My motor dies out. I pull to the side of the highway where she rests just off into the grass. Temps were fine, I know oil pressure was "good" moments earlier (yes, I check my gauges all the time, but who really trusts that oil pressure gauge)
It made no other sounds, just died out.
The check engine light came on as I was pulling over, so I'm sure it threw codes!
I called AAA, got my tow the 20 miles home (not the way I was GOING to go, but in a tow truck it wasn't all about the cruise anymore!)
It cranks, but doesn't fire. Before I do any real diagnosis, I'm going to read the codes.
So, today, I sit at work, thinking - what will it be?! Crankshaft position sensor? I can't wait to go home n' read the codes. I'm debating picking up a crankshaft sensor before I go home since I hear they all die about 100k, and I'm at 108k now, and it's one of the first things people seem to try.
Part of me wants to have it be low compression so I can do something cool with it, like a stroker, or a v8 swap or... a diesel and veggie oil for fuel! I don't really want it to be down for the rest of this season though... Anything other than a stroker would take quite a bit more time.
Any thoughts on other cheapo parts to pickup before I go home? Nearest parts store is 30mins from my house, so guessing sometimes really saves time. :P
Fuel rail has pressure. I have no spark from the coil.
I did swap the crankshaft sensor on the bellhousing of the transmission. No change.
Out of curiosity - on a stock jeep, does the sensor fit all the way out without having to lower the drivetrain?
I've built a custom mount between the frame rails for mine, shoving it up a bit more into the body lift, and mine needed to be lowered to get it. Project went from 1 bolt to about 20 after that. lol!
So, with no spark - Who controls it. How would I test the coil ? Can I test to see if the ECU is telling it to spark somehow with a test light? A coil's cheap enough, but testing to verify it's dead would be cool.
I found another oddity. Theres what appears to be a ground strap dangling by the crank position sensor. Where would the two ends go to originally? I took a look around but I cant see the strap from the top of the motor.
I know this is a little late but this is what the FSM says about testing the ignition coil.
Sorry if that's a little blurry, I'm at work right now and it's the best I can do on this crappy PC. I think I would agree with checking the cam position sensor next. Here is what the FSM says about that.
Hopefully that can help some. This sounds like an electrical issue for sure. If you don't have an FSM it might be a good time to get one.
Well I finally found the solution and my Jeep now runs.
As embarrassing as it is, I have to tell it so that others may gain benefit to it!
It was a fuse.
F21 in the fuse box. One of the little ones. I checked all my relays and all the big fuses and had no idea that one of those little fuses were anything more than horn/door/lights, usual BS... Sure enough, from a topic here in Jeep Forum, it's "Ignition Coil Fuse"
Unbelievable, but I'm glad it's over. Now I have spare parts to diagnose next time, since I know most everything is good. I'm guessing my coil is on it's way out if it's pop'd that fuse. Now I have one and will be ready!
Thanks much for the help folks! I also now have the FSM for my Jeep.
You do realize the very first step in troubleshooting is check the fuses....all of em, not unless your absolutely sure your on the right circuit.
I'm sure you learned just a little more about your jeep now.