1998 Cherokee, manual with 256k miles. I had issues starting about a year ago and bought the Napa starter that was frequently recommended in other threads. The issue ended up being the clutch safety switch, but I kept the new starter on there and kept the old one as a backup.

I had no issues starting the vehicle until a few weeks ago. Looking at videos from my security cams I can see that the final time that it successfully started, there was about a second delay from the crank to when it normally rolls over, but it did roll over after that pause. The first time that it wouldn't start it sounded identical, except it didn't roll over that time. Since then it's just cranked without getting close. I've tried a battery jumper, charging my battery, and using jumper cables from another vehicle and it still just cranks without coming close.

Going through no start threads I started checking the usual culprits and easiest fixes. I also bypassed my clutch safety switch to rule that out. I had a buddy help me rule out fuel, he also verified that I was getting spark (at least on one sparkplug anyway), I replaced the CPS, I haven't gotten anywhere though.

It is cranking but it seems like it's weaker than normal. I noticed that my heater core is leaking coolant right above the starter, so I thought maybe something happened electrically. I swapped out my starters to the old one that I know was working, I also tested it prior to install and it appeared to be functioning properly. I noticed on installation that the teeth of the flywheel were slightly chewed up (pic attached), but only in the location where the starter would be since it hasn't been starting, which to me implies that my issue is that the starter isn't successfully turning the flywheel. I don't know how to diagnose the cause of that though. I did confirm that I easily get movement when I put a breaker bar on the crank pulley and rotate clockwise.

I basically had no mechanical knowledge prior to this finding this forum, so I'm limited, at best. I've verified that I'm getting over 12 volts on my battery, 12.2 volts at the positive stud on the starter, but I'm only getting like 6 volts on the stud that the ignition wire goes to when the key is turned. Is the 6 volts normal? Is that possibly my issue, that the starter isn't getting enough juice to turn the flywheel? I've tried the screwdriver trick of connecting the positive stud to the ignition wire stud, on both starters, and it won't start doing that either (I have not tested the voltage at the ignition wire stud while doing that however). I assumed that would eliminate the voltage being the issue, but I'm not sure. Like I said, the starter sounds weaker than normal, but that could just be what it sounds like when its not able to turn the flywheel. Is it possible that the flywheel is stuck, or not turning as easily as it should?

Any ideas or help would be greatly appreciated. TIA


Chewed up flywheel teeth

 

Is this jeep for sale yet?

 

Are both these starters soaked in engine oil?

 

It's a little hard to sort things out from your post but the fact that 6 volts is showing up when you crank it, it cranks slow, and jumping the battery doesn't help suggests that maybe the battery cables/cables to the starter are rotted under the insulation or connections/grounds are bad
MIght try cleaning the connections/ grounds/ replacing the cables.
If you wanted to live dangerously you could go directly to the starter (with it in the vehicle) with a known good battery and good jumper cables and see if it cranks

(If you get 12v with no load and 6 when you crank that's known as flunking a load test)

 

I was thinking bad connections. Corrosion and such is pretty common. The teeth on the flywheel don’t look too chewed up. Even without mechanical experience I think you would be able to tell if the starter was just spinning without turning the engine.

Replacing the battery terminals or at least cleaning them and your batter posts is a good start. Sometimes you get voltage that looks good but corrosion/poor connections mean it can’t deliver the current.

Also cleaning the grounds will be good no matter what is wrong. Lots of pics online with locations. I like to add some dielectric grease to all my electrical stuff exposed to the elements.

When you measure voltage you can help get a good contact by really scraping into the metal to break off any corrosion.

But it sounds like it is cranking but not starting? Did you get a cheep CPS or a mopar one?

 

The old one was, not the new one. I had the leak fixed prior to replacing the starter.

 

I didn't realize I had these replies or I would've gotten back here sooner. Thanks for the input.

I replaced the cables when I had the last no start problem, at the same time the starter was replaced. I also cleaned all of the grounds then, but I can double check all of the connections and grounds. I have a pretty unique tax situation, which leaves me paying pennies on the dollar for parts, since I can expense them, it's my daily driver for work. Since that's the case, I had tried a dorman CPS, but I've now ordered a Mopar one. I also have a Mopar TPS and MAP sensor on the way. My battery was nearing the end of the line so I'm replacing it too. I'll be working on some of that stuff tomorrow, some of the parts are on the way.

I think I might give using some jumper cables directly to the starter a shot. Fortunately my sister has a spare vehicle she's been lending me but I don't want the XJ sitting too long without running, it's been 5 weeks now.

Thanks again.