Dead XJ

[Extinction]

Just got home from our cabin with the XJ. U packed and went to start it to move it out of the way. When I turned the key everything turned on like normal then went to crank it and it clicked and everything went black. Tried a few times and nothing. No lights. Nothing. Auxiliary lights wired direct were the only thing that worked. Checked the battery and was at 12.38. Grabbed the terminals and they were tight. Really never saw this happen before so was pretty clueless. Thought maybe the ignition switch. Wanted to see if it felt any different. When I put the key in to try it again the lights all came back on. I turned it and it started. Turned it off and on 5 times. Then went to shower. Came back out and tried it again. Started right up. What could this have been because I don't need this happening while at my cabin as it's not near phone service if I needed to call for help. Would rather the problem fixed rather then cross my fingers and head out.

 

[Anak]

I would go after your battery cables and their connections at each end.

I had something very similar happen with my Suburban. Got home one evening and shut it down, but then went to re-start it and everything went black. Dead as could be. I didn't have time to deal with it that night. I had a networking meeting the following morning (drove my work truck, Suburban was for family purposes) and one of the other guys was a mechanic (owned his own shop). I related my problem, he couldn't think of anything right off but several minutes later said "Hey, you have side post terminals on that Suburban don't you? Go home and tighten your terminals and see if that doesn't fix it." He was right. That was it. I bought him breakfast the next week.

While your posts may be tight, you may have an issue at the connection between the cable and the post clamp, or between the cable and the lug at the opposite end, or between the lug and the starter or the lug and the block. There are a number of potential failure modes, but given that your direct wired features were working I would go after the wiring between the battery and the PDC first.

 

[Extinction]

I have an Optima battery with top posts which are hooked to the normal connections and the side posts have all my accessories. I didn't see anything obvious last night but did grab the cables and tried twisting to see if they were loose. Maybe it is in one of the connections. I'll pull them all tonight and give them a cleaning.

 

[Unclewolverine]

Definitely a thin layer corrosion on the terminals, had it happen to mine. Thought my starter was going, cleaned the posts and cable ends, haven't had an issue since.

 

[Tim_MN]

Clicking and not starting is usually a low voltage issue from:

• dirty, corroded, damaged, or loose battery terminal or wire connections
• internally corroded battery wires
• a short circuit or parasitic drain
• a failing battery
• a failing alternator
• leaving the lights on

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. Copper wires should be copper color, not black or green. Battery terminals and battery wire connectors should bright silver, not dull gray/black and corroded. Do the same for the grounding wires from the starter to engine block, the ground wires at the coil, and the ground wires from the battery and engine to the Jeep's frame/body. You must remove, wire brush, and clean until shiny the cable/wire ends and whatever they bolt onto.

Jeeps do not tolerate low voltage, bad wire connections, or poor grounds.

Place your DVOM (Digital Volt Ohm Multi-Meter) on the 20 volt scale. First check battery voltage by placing your multi-meter's positive lead on the battery's positive post ( the actual post, not the clamp ) and the negative lead on the negative post. You need a minimum of 12 volts to continue testing. Next, leave your meter connected and take a reading while the engine is cranking. Record this voltage reading. Now connect your positive lead to the battery terminal stud on the starter and the negative lead to the starter housing. Again, crank the engine and record the voltage reading. If the voltage reading at the starter is not within 1 volt of battery voltage then you have excessive voltage drop in the starter circuit.

Typical voltage drop maximums:
• starter circuit (including starter solenoid) = 0.60 volt
• battery post to battery terminal end = zero volts
• battery main cable (measured end to end) 0.20 volt
• starter solenoid = 0.20 volt
• battery negative post to alternator metal frame = 0.20 volt
• negative main cable to engine block = 0.20 volt
• negative battery post to starter metal frame = 0.30
• battery positive post to alternator b+stud = 0.5 volt with maximum charging load applied (all accessories turned on)

Have your helper turn the ignition key to START while you tap gently on the starter with a hammer. If the engine starts, you probably need a new starter.

Test the output at the alternator with your volts/ohms multi-meter. You should be measuring 13.8-14.4 volts. Have the battery, starter, and the alternator Load Tested for proper function inside a test machine that applies a simulated work load. Handheld testers are inaccurate and will often pass faulty parts.