vroomvroom

So I've been trying to diagnose this problem for a while now. The Jeep will start right up, but when you get to your destination and turn the Jeep off, it won't start back up. If you short the starter, it WILL start up. Any ideas?

If you try to crank the Jeep in this scenario, the radio turns off and the brake light too indicating it thinks it is trying to start.

- A few years back, I refreshed all the power and ground cables.
- Battery is a few months old.
- Alternator is several years old, but seems to be fine.
- Cleaned the NSS today. After cleaning, I checked that the reverse lights come on when put in reverse and the Jeep started right up after cleaning the NSS.
- Injector rail is wrapped.
- Injectors are wrapped.
- Fuel pump and fuel pressure regulator are several years old, but I haven't had an issue with them.
- Spark plugs and wires are several years old now, but I haven't had an issue with them.
- CPS is several years old, but never had an issue with it before.

Any ideas? Or what you went through?

poni

if it cranks when you bypass the starter solenoid I would suspect that. Maybe the solenoid is on the way out and doesn’t like the heat. A starter is pretty cheap, I’m sure there’s a way to test the solenoid itself but I’ve always found if it works when you bypass a part that’s usually the culprit.

vroomvroom

I could see that. The starter hasn't been replaced since I've owned it and I don't know the history of the starter or starter solenoid. I will say, oil had been leaking on the starter for a while. I found the culprit to be a combination of the oil filter adapter seals and oil pressure sensor right above it. Both of those leaks have since been fixed. Oil does a number on the starter and could have damaged it prematurely.

I'll look into that. Thanks.

HatonXJ

What you say it won't start do you mean it cranks but won't fire or it will not crank?

vroomvroom

It won't crank at all. As in it doesn't click click click. The Jeep thinks it's cranking when it really isn't. You can see the usual signs of cranking like the radio powering off and the brake light as well.

I bought a starter but haven't had a chance to put it in yet. I've been sick recently. Hoping to put it in soon.

HatonXJ

The 99 i just bought wouldn't crank either. I pulled the start relay and jumped the power to the starter wire and it cranked. That confirmed to me the starter was good.

I ended up with a faulty NSS. I removed it and disassembled it, cleaned it and put it back in. With a little gentle abuse of the shifter I got it to crank and start. Installed a new NSS and its good.

Long story short it was an easy way to test the starter before buying one.

I carry a jumper wire just incase I'm in this situation again.

XJChang

Mine does something like this too, not every time but every once in a while, it wont start in park, lights turn off but no sounds from starter or similar. Put it in neutral and it starts right up, if you can start it in neutral its the NSS

Actually I just saw that you cleaned the NSS, seems more like something electrical with the starter itself

Saudade

Did you clean the contacts inside the NSS and verify the little springs were OK?

You could bypass the NSS using a jumper to rule it out. Jump pins B & C on the main harness side. You can also check for continuity on the NSS side when in Park and Neutral.

vroomvroom

Sorry, I haven't had a chance to look at this anymore. I'm still getting over being pretty sick.

When I cleaned the NSS, it was pretty gunked up inside. I took it apart and used some contact cleaner as well as a soft bristled brush to scrub. After cleaning very thoroughly, I used a fine grit sandpaper on the contact points to shine them up. I took the springs out of the pivoting arm and cleaned inside of that pocket area well and used some dielectric grease for prevention. When I put the springs back in, I could push down but it would instantly pop right back up, so that was a good sign.

After cleaning the NSS, I could confirm it started right up the first time. I drove it around town and finally went to the grocery store. When I got back in from getting groceries, it wouldn't crank at all. I had to put the ignition in the "on" position and then use the trusty 'ole screwdriver on the starter to get it running. I can also confirm that the reverse lights do come on like they should. Apparently, no reverse lights is a symptom of a bad NSS.

I do plan on testing the starter relay and starter solenoid for issues. I could try bypassing the NSS like you were saying as well.

xjgerry

In my similar journey with a '99 the usual fail was no fuel pump coming on: crank no start. I swapped the relays around
and found one worked. Until it didn't.
Over time I identified 2 other similar fails. 1) The dash lights up but no other effect- no click/ no dimming no crank. I "think" this is the ASD.
2) I can't think right now but similar.
Swapping around the relays would either get me going or cure 1 lose another.
The pricier Napa Eclin relay is easy to get and works. I bought the remaining 3 but as a matter of pride I won't put them in until the current config fails then replace only the offending circuit.
Life is uncertain but that means little when my Cherokee starts
Hope this helps somebody

Saudade

Well, it does sound like a heat related issue. Since it starts when you jump the solenoid (assuming this is when it won't crank with the key), I would surmise the starter and solenoid is OK (as well as your CPS, etc.). That really only leaves the NSS, Starter Relay and Ignition Switch (assuming fuses and wiring is OK). I don't recall ever reading about a heat related failure of the ignition switch. As XJGerry suggests, swap the relays around using the AC or Fan relay. Make sure the relay contacts in the PDC are clean and seated correctly in the holder.




You can also probe the contacts on the relay holder.

Pin 6 comes from Fuse #3 (40a) in the PDC. Should always have 12V.

Pin 7 goes to the starter solenoid. You can check for continuity to the solenoid. Jumping across Pins 6 & 7 should also crank the starter regardless of Key position. Key on should start and run.

Pin 8 comes from the Ignition Switch. Should only have 12V when key turned to START.

Pin 10 goes to NSS. Should show continuity to ground when shifter is in Park/Neutral.

Naturally, doing this while everything is "cold" won't reveal anything. You'll need to get it hot enough to recreate the issue, then quickly test before it cools off.

BillyBoy

I don't want to be elementary here, but it sounds like a bad Negative cable/ground.

The jeep starts reliably after sitting at your house for an extended stay, starts, runs, then won't restart, with the dash (Radio) readout off? What condition is the main negative cable in?
Try hooking a jumper cable from the negative terminal to the engine, and the other clamp of the cable to the negative of the battery also, and to the negative on the Starter.
Try starting it.
if it runs, your problem might not be the connections you refreshed, but the cable itself.

It might be a good idea to have cables and plan/test this by starting it at your house, running it around the block, and coming home. If you try starting it again and it fails, try "essentially" reinforcing your ground wires, following what I said.

That way, you don't need a tow.

The Radio is a key here... it's very ground sensitive, and depends on the engine-to-radio ground. If the engine isnt grounded properly, itll blink out and die.
Hooking up a jumper cable from the negative to the engine and body (at the same time) also might also might make it work.





Good Luck. God Bless.