2000 XJ Slow Crank sometimes No start

Alright so a few months ago I went out on a cold morning to start my XJ and it cranked very slow but did start. The issue has progressively become worse, however it is not consistent meaning it only does it sometimes, usually in the morning when it's cold. My first idea was the battery, which I replaced. The issue still proceeded. Then I read up on the forums about the check valve in the fuel pump being the culprit. So I tested this by first turning the key to the prime position and letting fuel go through. This did seem to help it start quicker, but still did not fully rid the issue. As of the other day, it has not started on me twice. I went to start it after coming out of the store the other day and it was a slow crank. I tried priming it and that made matters worse. At that point, it would not even crank. I just heard a click....click when I turned the key. I had my buddy come up and we tried to jump it which did not work. We left the jumper cables connected and tapped the starter with a hammer and it started to crank finally. After a few seconds of cranking, it finally fired up. So I'm wondering what this could be? I am suspecting starter because I would think it would still crank even with a bad check valve. But I was also thinking maybe there is a draw on my battery somewhere....Any ideas? Please help. Thank you.

Slow cranking is solely a function of battery power, battery connections, and battery cables. (nothing to do with fuel pump) The clicking at the end is the starter solenoid telling you that it's not getting enough power and can't even keep itself energized.

Be sure and use an external charger on your new battery for awhile.
I've seen 90% dead batteries on the shelves at the autoparts store so my routine with new batteries is to 2A charge them for a day or 3 before installing.

Get one of those little battery cleaners that look like bristly christmas trees. Clean the inside of the battery clamps so they are shiny. Clean the battery posts with the bristly socket so they are shiny.

That cleans the resistive coating off the metal of the clamps.

If you have bubbly looking insulation on the battery cables (usually near the battery) you may have corrosion under the plastic which has reduced the number of strands of the cable that can carry power. Powder coming out the end of the plastic covering is another giveaway. Too thin battery cables from corrosion means the current can't get to the starter for it to go full power.


Then check for good clean (bright, shiny) connections at the starter and the end of the ground cable.

Clicking and not starting is usually a low voltage issue from one or more of these:

• 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.

Agree, this sounds like either a connection issue OR a ground issue. Never overlook grounds. Freshening them is never a bad idea. More on that below.
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Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea, and the investment of your time in this procedure is always well worth it!

You can't tell much of anything by looking at ground connections!! You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. Be sure to remove all paint from any ground connections.

Start with the one on the back corner of the head, and where it attaches to the firewall, as it deteriorates over time and is an area that makes it susceptible to damage. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support.

If all your cables are CLEAN it's the starter.

Replace the starter.

I know this sounds dumb but it cost me a battery about a year ago. Make sure your glove box is closed all the way...

I kept having a dead battery and I would charge it every day and it would just keep dying within a few hours of parking it somewhere. One day I got in my car in the middle of the night and looked over and saw the glovebox was barely cracked and a tiny bit of light was shining on my windshield... It was like 1/2 latched shut, didnt fall open or anything while I was driving around for over a week. Just a cheap thought to look at real quick if youve been in your glovebox recently

And I noticed the light the day after I bought the battery, just my luck