Ok working on my sons 98 XJ Classic, has 4x4 & the 4.0 motor. Problem started like this, driving down the road & volt meter jumping all over, loss of power from the motor as well, pulled into station & now won't start. I come to help swap batteries, jump it, clean all connections, won't start! I pulled the starter thinking recoil is bad. Took it to Auto Zone for bench test.....all good.
So now I reinstall the starter thinking I need to get this home! Come up with have the son hold over ignition & cross the + - at the starter...ureaka it started!! So get it home, thinking noe has to be the NSS, installed a new one & nothing different.

Then tested battery (12.58 volts), Test alt at the battery, (13.5 volts at idel 14+ when reved), checked volts at starter 12.5. Tested the Crank position sensor has volt, forgot also checked all related fuses & starter relay all good. Can it be my main computer (BCM) if there is one on this Jeep? All thought welcome here I am completly out of any.

 

did you test the ignition module??

 

Did it run fine for the drive home? Sounds like a short or bad ground maybe? There are a couple places to check- obviously off the battery, but the braided line at the fire wall and possibly a ground wire at the bottom of dipstick tube. There is apparently a nut that holds it in place, but I think that's an earlier model thing. Can you get a code reader on it? That may help give you a direction. Possibly one of the sensors like TPS, or IAC valve.. Maybe an o2 sensor... But none of those would account for not starting at all... Maybe he CPS?... Idk man.. Welcome to CF, though.

 

Kind of confused here. You said it won't start, but also that you tested the alternator with the engine throttle applied. So please clarify if it STARTS, cranks but does NOT start, or is intermittent.

Regardless, one of the things you need to do is to freshen the electrical grounds for the engine. Electrical life starts with a solid ground.
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Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea, and the investment of your time in this procedure is always well worth it!

You can't tell much of anything by looking at ground connections!! You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. Be sure to remove all paint from any ground connections.

Start with the one on the back corner of the head, and where it attaches to the firewall, as it deteriorates over time and is an area that makes it susceptible to damage. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support.

 

ok to clairafy better when I turn over the key its a no crack at all. All light & stuff work just not the "starter". The only way I can get it to start is by having somone hold the key in the ignition while I cross the + - at the starter, then it stars. This is how I did the alt / battery testing.

 

Almost forgot, no it did not run good for the ride home. Same stuff..volt drops, non shifting at the trans, motor power loss...ect.

 

Did not test ignition mod, where is it & how is the testing done?

 

It is on the steering column. I believe you have to have a ignition tester for it.

 

O.K. Just cleaned the 2 grounds you talked about. All nice & shiney, but still nothing when I turn the key over just dead!

 

Is anyone still here?

 

Go ahead replace the starter bud ! And just cuz you replaced the Nss may not mean you did it right ! You have to adjust the big nut and put de electric grease inside it ! Just trying to help! I would check transmission fluid also

 

Wait, do you mean when you get a new NSS you have to put the electric grease in it.........it does not come pre-gresed???

 

Yes, it comes pre-greased. He's thinking of rebuild.

I'm curious, do you have reverse lights? Check that.

 

Just checked that & NO .......so I got back under & adjusted with it in reverse until I got ther reverse lights, then locked it back down. Back into the Jeep & samething, no crank in park/Neutral. Slid the shifter back & forth couple a times & same result. But after all this the light are again not coming back on when in reverse, this ##@&** is pissing me off.

 

try the parking switch stuff. mine was bad and caused me to not be able to start and when i did itd run kinda funny. replaced it and boom fired right up. went out again. now i can only start in "N"