Jeep Died on the Highway... CPS?

My Jeep died on the highway on the way to work today. It just completely shut off. For about a minute I had nothing. No crank, no lights, no emergency flashers. After about a minute it all came back. It will crank and act like it wants to start but die immediately. From searching it sounds like either a CPS or PCM. I'm at work so I can't test for spark or fuel right now. What do you guys think?

Make sure those battery connections are good and clean. Sounds to me like the computer did basically a hard reset and has lost all it's memory. You'll probably have to give it a little throttle to get it to fire, then keep on the throttle for a few minutes so it can re-learn how to idle.

XJ's do not like dirty battery connections (or grounds, have a look at those too) at all. A couple years ago I had issues with my battery cables that caused very similar problems. First time I was heading out and it cranked, fired for a split second, then completely died. No lights, crank, radio, interior lights...nothing. Like you completely removed the battery. After a mintue or two it all came back, but the computer had reset and it wouldn't idle.

Same thing happened a couple months later while I was on the highway, only I noticed the volt meter pegged out just before I lost everything and it shut off. While waiting for a buddy of mine to bring a trailer out and pick me up on the side of the road, I unhooked the battery and cleaned the connections, just for grins. Fired right up like nothing had happened after that.

I just checked those this weekend. I was getting a P1682 charging system low code. I made sure the cables were clean and tight and that my grounds were good. I'll double check when I get home.

Died on the road, not cranking, starting and then stalling, are all symptoms of low battery, and a CEL code that reinforces the low voltage suspicions.

low voltage issues from:
• leaving the lights on
• a failing battery
• a failing alternator
• dirty or loose wire connections
• internally corroded wires

Perform routine maintenance of the start and charge systems. Remove, clean, and firmly reconnect all the wires and cables to the battery, starter, and alternator. Look for corroded or damaged cables or connectors and replace as needed. Do the same for the grounding wires from the starter to engine block, and from the battery and engine to the Jeep's frame/body. You must remove, scrape, and clean until shiny, the cable/wire ends, and whatever they bolt to. Jeeps do not tolerate low voltage, bad connections, or poor grounds.

Have the battery, starter, and the alternator Load Tested for proper functions. Hand held testers are seldom correct, test in a machine that applies a simulated work load.

If its a charging/voltage issue would it still crank fine? It cranks like it wants to start it just doesn't start.

If voltage drops low enough, the engine will die, you will have difficulty starting, and it will probably stall right away.

I will check everything out in about an hour and post what I find. Thanks!

Found my problem. I thought I heard a pop when it died.







I've never seen this before. The cap/rotor is only a couple months old. I should be able to have it replaced. Anyway I can check my dist. to make sure it's ok?

That's crazy!! What were you doing, like 120mph?

It happened right when the truck downshifted driving on the freeway going about 55. It was going up the same freeway I take to work everyday. It is a decent incline though.

Wow. Was everything seated properly? Might want to have/test the coil.

91to99 said:

Wow. Was everything seated properly? Might want to have/test the coil.

Click to expand...

I assume it was. It's been on for about 500 miles.

Thats an impressive sight...
I have experienced carbon tracking and pieces of the terminals missing, but never burned thru; thats alot of heat.
When you replace the cap & rotor; place a small amount of dielectric grease on the terminals and ensure the plug & coil wires snap to the terminals.

CharlesS said:

Thats an impressive sight...
I have experienced carbon tracking and pieces of the terminals missing, but never burned thru; thats alot of heat.
When you replace the cap & rotor; place a small amount of dielectric grease on the terminals and ensure the plug & coil wires snap to the terminals.

Click to expand...

Something happened between the top of the rotor and the coil plug. It blew completely off and you can see the burned line on top of the cap where it was still arcing as it was moving. The coil plug is still firmly seated in the boot.

In all my years of working on cars I've never seen that happen. That's just crazy. Put it on a plaque.

where's the rest of the rotor? It looks like the contact point of the rotor failed and the electricity from the coil had nowhere to go (and melted the cap when it jumped the extremely large gap to where ever it went)

Check your distributor shaft for excessive wobble while you have it apart. It may need replacing too.