Andrew Peakman

I have had an odd problem with my 99 xj 4.0 the past 3 days. Past 3 mornings hop in , turn key over , everything lights up , won't turn at all . Took my truck to work , come home , the thing starts right up after some wiggling of battery cables . It drove me to the store , turned it off , started again to leave the store , and was parked for the night . Exact same thing happened yesterday and this morning . So this morning, went and got all new battery cables , installed them and cleaned every connection and ground spotless including the starter and alternator . Started up great rest drove great . Went to start it again and it almost didn't do anything , held my key for maybe 4 seconds and it went . Is this an issue with the wires inside the steering column possibly ? Im worried to take it anywhere and get stranded

Andrew Peakman

Since it had that one little cough up however , I've started and stopped it about 10 times and it seems fine . I'm just not sure what this is even a symptom of, or if you guys would reckon I solved the problem with new batt cables

lawsoncl

Does it start in neutral, or if you wiggle the shifter? That would point to the neutral safety switch on the side of the trans.

Andrew Peakman

No , it doesn't seem to make a difference . It just happened again , I disconnected terminals , cleaned and kinda scuffed up the actual posts . Wouldn't start , got pissed and turned the key all the way very rapidly like 10 times and it fired and it runs and drives powerfully no dim headlights anything ...

xjnm

Could also be a CPS issue or your starter solenoid is having trouble engaging. My buddy's cherokee wouldnt start unless you hit the starter with a hammer while turning the key

Andrew Peakman

Cam position sensor ? Also , the solenoid plastic part seemed to twist slightly In it's socket if you know what I mean , when I was re assembling it,
​​​​​​ is that normal ?

xjnm

Crank position sensor. There's lots of info online about the symptoms of those going bad, I don't know much about them though.

As far as the starter, next time you go to start it and it won't go, have someone tap the starter solenoid with a hammer and 2x4 while you hold the key. If it starts then, then you know that's your problem.

Andrew Peakman

Funny , I am a framer and have those available at all times hahaha. Will do . Hopefully I can figure this out before it leaves me stuck at work hahaha.

Andrew Peakman

It has a new crank position sensor . I think I've narrowed it down too the starter/solenoid , or my park neutral switch . Ill go for solenoid first .

lawsoncl

From his description, I assumed that it wasn't cranking at all which would not be the crank or cam sensors. Suspects would be the battery cabling, starter solenoid, starter relay, neutral sensor, etc.

Sig220

Might want to check your ground connections in the engine bay to battery. I should say all grounds in the engine compartment. If you haven't checked them (taken apart and cleaned them) they are due!
Plus, it just takes your time to clean the grounds, no parts to buy unless you replace wire terminals.

Good Luck!

Andrew Peakman

If my starter motor will spin when I short out the two posts , but isn't actually engaging , is that a sign of the the bad starter solenoid ? Like if I short it out (suggested by youtube) it seems to be spinning strongly , but not engaging to Anything .

Sig220

If I remember correctly, the starter has a spring or a grooved path in the shaft behind the gear that extends and retracts to spin the flywheel. If you get the starter to spin by jumping the solenoid and the gear does not extend, I think its indicative of your starter having a problem and needing to be replaced.

Good Luck!

lawsoncl

There are a couple of starter solenoid designs, I don't recall which the 99 used. One design has the solenoid extending the shaft and then making electrical contact to power the motor. In another design, the solenoid just makes the electrical contact to power the motor, and it's the rotation of the motor that forces the shaft forward to engage the flywheel as Sig220 described.

The best way to troubleshoot is to measure the voltage at the solenoid while trying to crank. If you don't see voltage to the solenoid to activate it, then look upstream at things like the NSS switch, starter relay or ignition switch.

Andrew Peakman

I just put a new starter in, and now I can get the Jeep to start by jumping the new starter ,I still can't start the thing with the key . I think this means it's the neutral safety switch ? This jeep had an interlock installed in it a few years back 😅 so my only other thought is that wherever the interlock technician cut into the steering column /driver floor wires is going faulty.