Issue with Starting

[Pipewrench Scratch]

To begin: (This is my first post here, so I apologize if this is in another thread somewhere, I tried to look around for one).

Long Version (I'll try to put a shorter version below). Thursday I was out with a buddy and my Jeep died. I was in 4WD High, 2nd gear (I think), going 25-30 mph, probably 3000ish RPMs, (I don't really remember). I figured maybe my engine overheated, popped the hood for five minutes and she started right up. Drove probably an hour and half with no issues.

Friday morning I left for work, turned out onto the highway, got to probably about 55 mph in 3rd before it died again. Let it sit for a few minutes, but had to admit defeat and have my brother tow me home (embarrassing). Tried to start it again Friday after work, no luck.

Saturday (today as I write this) morning I decided to see if I could fix it.

The battery is good, when I turn the key, the starter engages and tries to crank the engine, but it never starts. I was getting gas from the fuel distributor release nozzle (no clue if that's what its called) when I try to start it, so I don't think its the fuel pump.

Pulled off the ignition coil, put a screwdriver into one of the spark plug sockets and held it to bare metal to test for spark. No spark.

Everything I had read or watched said it was one of a few things, the most likely is a bad Crankshaft Position Sensor. So I grit my teeth and bought one. Made sure to take the old one with me to verify before I bought it. Anyways, after replacing it it, she still wouldn't start. I thought maybe it was too dirty, so I pulled it off and cleaned the area better than I did the first time around. Still nothing.

Next two things I read to check were the computer module and the ignition coil. Hoping to not have to deal with anything electronic I grit my teeth (again) and went back to the same O'Reilly's and bought a new ignition coil and six plugs (cause why not?) and rushed home.

Changed the plugs, slapped on my brand new ignition coil and boom! nothing.
Spent another couple hours checking all the grounds I could find (probably should have done that first, oh well). Nothing really stuck out to me, although I disconnected and cleaned one that looked dirty (no effect). About then I got tired. And hungry.

Checked and rechecked all fuses that had anything to do with starting. (And a few that didn't). So now I'm out of ideas. My best guess is something electric, but I have no idea what.

If there's anything I've missed or overlooked let me know. I'm not very mechanically (or electrically) inclined, and this is also my first car. Also if you need some extra clarification let me know.

Short version: Jeep won't start. Battery is charged. Starter is cranking. Fuel is pumping. Ignition coil is not sparking. Crankshaft Position Sensor has been changed. Ignition Coil has been changed. Fuses are good. Spark Plugs have been changed. Beer has been drunk. Any help or tips would be appreciated.

 

[Chris]

I'm going to insist you edit that post to add paragraphs It's barely readable without them (the long version at least).

What brand of crankshaft position sensor did you change it with? If you used anything other than Mopar, that may be part of your issue, as these things are highly documented to reject any sensor other than OE Mopar.

Is it throwing any codes? If so, what are they.

If the ignition coil isn't sparking, that seems to suggest the coil packs could be bad.

 

[Pipewrench Scratch]

I'm going to insist you edit that post to add paragraphs It's barely readable without them (the long version at least).

What brand of crankshaft position sensor did you change it with? If you used anything other than Mopar, that may be part of your issue, as these things are highly documented to reject any sensor other than OE Mopar.

Is it throwing any codes? If so, what are they.

If the ignition coil isn't sparking, that seems to suggest the coil packs could be bad.

I'll see what I can do.

It was a "Standard" brand crankshaft sensor, not Mopar. Maybe that's it.

The ignition coil I replaced was the long one piece type, which I replaced with a long one piece type. I didn't know that there was a different kind until I saw a picture of one in another thread. I'm not sure what you mean by coil pack, as mechanic work is new to me (first car and all)

I don't have a code reader, I'm a what you call a new (bad) mechanic.

 

[Pipewrench Scratch]

Okay, so I didn't know that you could get a code by doing the key thing, I thought you needed a code reader. (Again, bad/new mechanic) Just tried it, the odometer would go blank and then say "DONE" without a code and the check engine light wouldn't give a code either.

 

[freedom_in_4low]

A lot of this going around. I just went through a crank no start on mine but it's a 99 so completely different ignition system.

At least on my 99, power goes through about 3 different fuses in both the fuse block in front of the glove box and the power distribution center before getting to the ignition coil. I think the factory service manual has probably been posted here, I would suggest finding it and tracing through everything from the battery to the coil packs on the wiring diagram.

Good job on the diagnosis you've done so far. Pretty impressive for your first vehicle.

 

[qslim]

I'm a what you call a new (bad) mechanic.

Just because you're new doesn't mean you're bad. No one was born with any of this knowledge and we all had to learn it somewhere, so ask questions and take advantage of all the experience folks on this board. You seem ready to dive into it so it sounds like you'll learn a ton.

I was getting gas from the fuel distributor release nozzle (no clue if that's what its called) when I try to start it, so I don't think its the fuel pump.

You're talking about the little valve on the fuel line similar to a tire valve stem? That's the fuel pressure test port where you would hook up a gauge to measure fuel pressure. It should carry around 45psi of fuel.

I'm not sure what you mean by coil pack, as mechanic work is new to me (first car and all)

The coil pack is the little black cube that sits on top of your spark plugs. You'll hear them called coils, coil packs, ignition coils, etc. Older TJs like mine only have one coil pack that distributes (via the distributor) voltage to the plugs via spark plug wires. Later models like yours have three coil packs integrated into a single rail that mounts directly to the plugs to provide voltage without the need for spark plug cables or a distributor.

Pulled off the ignition coil, put a screwdriver into one of the spark plug sockets and held it to bare metal to test for spark. No spark.

Can you elaborate on exactly what you did with the screwdriver to check for spark? For this kind of stuff I like to use a spark plug tester, you cat get them most places and they're very easy and more reliable than the old screwdriver method - something like this

https://www.amazon.com/dp/B0050SFVO2/?tag=wranglerorg-20

Everything I had read or watched said it was one of a few things, the most likely is a bad Crankshaft Position Sensor.

Yeah, what you're describing is symptomatic of a bad CPS. Our TJs have a terrible reputation for agreeing with aftermarket sensors so I wouldn't be surprised at all if your original sensor failed and the aftermarket one you installed isn't working correctly. I'd suggest returning it and getting an OEM MOPAR sensor.

Lastly @Chris has made available all of our factory service manuals in the TJ Resources forum. They're well written and have very detailed procedures for troubleshooting problems like this. Between your manual and folks on this board you should be golden.

 

[Goatman]

Just to double check (triple check?) When you used a screwdriver to check for spark did you have the metal screwdriver touching metal, or nearly touching? If it was making contact then it was grounded out and would make no spark.
Easy spark test method...
Pull a plug wire. Insert known good plug (you have 6 of them that you just replaced). Ground that sparkplug to the engine. Ideally it should have a good gap. A used plug normally will. See if that sparks when cranking engine.

That avoids the question of whether you have the screwdriver too close or too far from the grounding point. It should have a nice strong spark of whitish to bluish color. A weak orange to yellow will verify spark, but a possible poor coil. You should hear a decent snap when the plug sparks.

 

[qslim]

Just to double check (triple check?) When you used a screwdriver to check for spark did you have the metal screwdriver touching metal, or nearly touching? If it was making contact then it was grounded out and would make no spark.
Easy spark test method...
Pull a plug wire. Insert known good plug (you have 6 of them that you just replaced). Ground that sparkplug to the engine. Ideally it should have a good gap. A used plug normally will. See if that sparks when cranking engine.

Yeah that's what I was thinking, the screwdriver method doesn't work quite as well as just holding a plug to the head or block.

The only difference here is that the OP has a coil rail so he doesn't have plug wires to work with.

 

[Pipewrench Scratch]

So, quick update:

Changed out the aftermarket crankshaft sensor (CKP? CKS?), put in old one (figured maybe it was the coil that was bad, and the aftermarket sensor didn't work.) Still not starting.

When I tried to test the ignition coil before I tried the screwdriver trick. Later I also tried with one of my old plugs grounded to the engine, still no spark.

As has been suggested to me by a few of you guys I ordered a Mopar Crankshaft Sensor and found my receipt for the other one I bought. So I'm waiting on that now. Once that's in I'll try it again and be back with an update.

Thanks for your help, guys

 

[Pipewrench Scratch]

Latest news, got my Mopar sensor in Thursday. Put it in after work. Tried to start it, still nothing. Thinking maybe it was the aftermarket ignition coil I pulled it and replaced it with the old one. Still nothing.

Worked late Friday, I had already decided to take it to an actual mechanic. Didn't try anything.

Saturday morning, my brother and I were trying to figure out how to get a dead jeep with a burnt-out winch onto a trailer. We settled for a chain and a small tractor. While my brother was trying to get the right angle on the trailer, I just decided "screw it" and tried to get a code from the computer with the key trick. Surprisingly, I got one. P 0340. Looked it up, (though some of you might know what it is already), and found out it's a Camshaft Position Sensor (not crankshaft). Told my brother, went to town, bought a new sensor, plugged it in and boom. She started. Then died. Best guess was the engine was flooded from numerous starting attempts. So I started it again and kept my foot on the pedal for a few minutes to keep it going. Eventually it kept idling without my foot on the pedal.

So, it's solved. For now. Check engine light isn't on anymore. Couple things i still can't figure out. Why didn't it give me a code the first time? Did changing out the crankshaft sensor have something to do with that? Would that keep the computer from getting the right information? Anyways, she runs for now. Still have the new ignition coil. I'll probably swap the old one again pretty soon. Hopefully the aftermarket curse doesn't affect that too. (Side not: anyone want a slightly used crankshaft sensor that probably won't work? No? Good thing I kept my receipt.)

 

[qslim]

Good, I'm glad you gave it one last hail mary before towing it away and thanks for reporting back on the fix. I don't have any info for you on why you weren't getting a code before, I'm not sure of that logic on our TJs but maybe someone that knows will chime in.

As far as the new crank position sensor, it wouldn't hurt to keep it around as a spare as they do have a fairly high failure rate.

 

[stetsonaw]

THANK YOU for posting the resolution. My TJ has been doing this since Saturday. It’ll work, then it’ll die. 5-30 minutes later it’ll start again. Fuel pressure every time, so fuel pump is good. Ordered the Viper mod coil pack swap to get rid of the coil rail (been wanting to get it anyway, this was a good excuse). Will grab a camshaft sensor too. Did you use a Mopar one or aftermarket?

Thanks again!!