Jeep won't start when cold

[XbajajeepX]

Back to square one. The new battery didn't fix the problem

 

[scottmcneal]

I didn't read all of this, But how old are your cables? I had one that wouldn't start when warm(running temp) if i shut it down.

Maybe yours is the other way, when cold. Just thinking out of the box

 

[Lowrange2]

You need to diagnose the issue. The starting system on these things isn't complicated. When it's not wanting to start you need to start at the starter and go back up to the switch with a volt meter and figure out where the voltage stops.

The small wire on the starter tells it when to spin. If it's not getting voltage it's not even going to try.

 

[XbajajeepX]

Try jumping direct to the starter with jumper cables or crossing between the two starter wires with a screwdriver. Make SURE you are in park or it could start and run you over.

So I did this with a screw driver and it started up perfectly just now. What does this mean?

 

[xjnco]

It could be a number of things... Relays under the hood, ignition switch, bad grounds, bad fuse, these need located then wiggled and checked in the cold enviroment. You need to find a scematic of the starting system then trace or follow B+ from the battery throught the starting circuit. First make sure all the ground connections are tight. It's a time consuming process, I know.

 

[Lowrange2]

So I did this with a screw driver and it started up perfectly just now. What does this mean?

You're killing me.

It could be a number of things... Relays under the hood, ignition switch, bad grounds, bad fuse, these need located then wiggled and checked in the cold enviroment. You need to find a scematic of the starting system then trace or follow B+ from the battery throught the starting circuit. First make sure all the ground connections are tight. It's a time consuming process, I know.

^ This.

I'd start with the swapping around the relays under the hood. I guess it could be sticking when it's cold.

Also, have you cleaned the NSS yet?

 

[md21722]

The other posters are giving good advice. Trace the circuit to find the fault.

 

[XbajajeepX]

I've swapped out the starter.

Cleaned up the NSS.

Bypassed the NSS.

Swapped around the relays.

Installed a new battery.

I haven't had time to work on it lately, but I'll be picking up a test light tomorrow and trying to narrow things down a bit.

But now, even when it's cold out the jeep starts up fine. It did this to me a couple months ago. The problem seems to come and go.

 

[Lowrange2]

Finding the problem when it's not a problem won't be easy. I don't know what else to tell you.

Get a multi-meter instead of a test light and test for high resistance in the B+ wire that runs from the starter to the PDC.