HELP! 02 Starts then dies after about a second

[Shankster]

So I bought a 02 Limited, 3.7L 4x4 with bad rod-knock in November and just got the motor installed after a complete rebuild. It started just fine and I drove it around town, 4 or 5 times, probably 20 miles total with no real issues other than discovering the speedometer doesn't work. I was messing around with the speed sensor and associated wiring on the rear axle yesterday and then we had a foot of snow last night after being bone dry and super cold for about a month. Went to start it this morning to do a test of the 4x4 system in the snow and the battery was super weak and could barely turn it over. I tried cranking it several times (don't remember how many) till the battery was spent. Hooked up the battery charger for a couple of hours and then tried to start it again - battery was strong and it started up just fine, and then died after about a second. Tried again and again and again with exactly the same result - would fire up fine then immediately die. My gut tells me it's a key/security issue associated with the low battery and multiple start attempts when the battery was low. Does that sound reasonable? Is there a way I can reset the security system so that I can start from scratch? Or do I have a cam or crank angle sensor issue? Something else? Any suggestions where I start trying to figure this out?

 

[Billwill]

The early KJs...at least the Export models...have an Amber Key Symbol with a line going through it to show a problem with the SKEES Security System..newer models have a single Red LED on the left of the cluster.
Do either of these come on permanent or flash at you? Make sure the cluster bulbs for these lamps do work by holding IN the Odometer Reset Button while switching the ignition ON. All the gauges should move around and all Lamps should light up. This tests for blown lamps or lamps/LEDs deliberately disabled by previous Owners or dodgy car salesmen!

Does your Fuel Pump run?

 

[duderz7]

I'd look at feel pump too, relay if you're lucky.

 

[Shankster]

The early KJs...at least the Export models...have an Amber Key Symbol with a line going through it to show a problem with the SKEES Security System..newer models have a single Red LED on the left of the cluster.
Do either of these come on permanent or flash at you? Make sure the cluster bulbs for these lamps do work by holding IN the Odometer Reset Button while switching the ignition ON. All the gauges should move around and all Lamps should light up. This tests for blown lamps or lamps/LEDs deliberately disabled by previous Owners or dodgy car salesmen!

Does your Fuel Pump run?

The key symbol did show up when ignition was in the on position (prior to turning it to start) but quickly went out. I did hear the fuel pump come on briefly each time. Anyway, all a moot point now. I disconnected the battery and charged it overnight based on info I got off another forum for Jeep Wranglers, hooked it up just now and it fired right up. Someone on that other forum said that Jeep alternators don't have the juice to provide spark and fuel injection when the battery is at anything less than 12V - I was real dubious about that info since with any other car I've owned over the last 35 years, if the battery is strong enough for multiple good cranks (mine was) then it will start and continue to run. Is this a known characteristic with Jeeps (and other Mopar products)? I guess if it was a key / security issue it might have reset itself overnight with the battery being disconnected? I'm leaning towards the first reason though.

Anyway, thanks to both of you for responding - I'll go continue to chase the other little gremlins that are frustrating me and hope this one doesn't recur (although I think something is draining the battery overnight so I may continue to have this issue till I can isolate that problem)

 

[Duster]

So I bought a 02 Limited, 3.7L 4x4 with bad rod-knock in November and just got the motor installed after a complete rebuild. It started just fine and I drove it around town, 4 or 5 times, probably 20 miles total with no real issues other than discovering the speedometer doesn't work. I was messing around with the speed sensor and associated wiring on the rear axle yesterday and then we had a foot of snow last night after being bone dry and super cold for about a month. Went to start it this morning to do a test of the 4x4 system in the snow and the battery was super weak and could barely turn it over. I tried cranking it several times (don't remember how many) till the battery was spent. Hooked up the battery charger for a couple of hours and then tried to start it again - battery was strong and it started up just fine, and then died after about a second. Tried again and again and again with exactly the same result - would fire up fine then immediately die. My gut tells me it's a key/security issue associated with the low battery and multiple start attempts when the battery was low. Does that sound reasonable? Is there a way I can reset the security system so that I can start from scratch? Or do I have a cam or crank angle sensor issue? Something else? Any suggestions where I start trying to figure this out?

This situation *****. See my thread in this same forum just a bit down from yours that is titled Key WCM or PCM

Look on the dash at the sentry key light. Mine is a 2007 so this is just a red dot light. Tell me what that is doing, and meanwhile charge the battery. Try a slow charger while it is still hooked up for now.

Mine locked out after too many attempts and started doing NOTHING when I turned the key instead of running for 2 seconds and stopping. So with that in mind, just turn the key to the on position and see what the light does. Is your keyless entry working?

 

[Shankster]

This situation *****. See my thread in this same forum just a bit down from yours that is titled Key WCM or PCM

Look on the dash at the sentry key light. Mine is a 2007 so this is just a red dot light. Tell me what that is doing, and meanwhile charge the battery. Try a slow charger while it is still hooked up for now.

Mine locked out after too many attempts and started doing NOTHING when I turned the key instead of running for 2 seconds and stopping. So with that in mind, just turn the key to the on position and see what the light does. Is your keyless entry working?

Thanks for the response Duster. I got my problem solved - a lot simpler than I though, by charging the battery overnight like you suggest at a low (2A) rate. See my earlier post.

Hope you get yours figured out - my next step was going to be to unhook the battery and connect the 2 cable ends together overnight which some have said resets the computer. I thought that might reset / resolve the security issue I thought I had.