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.

 

How old is the starter? Also is your alternator putting out even volts? I had a similar issue on a car I owned and it turned out it was a bad starter and a loose connection from the alternator to the battery not letting me charge right and start right. Hope this helps.

 

Step 1. remove and inspect/clean the battery connections if not done, clean them till shiny.

Step 2. Clean all ground point in engine replace any that are corroded the ground strap at the back of the head to the firewall are commonly corroded.

Step 3 Remove the starter have it tested, willing to almost bet being that you tapped on it, and it started working somewhat then its bad, if so replace with a new if budget allows.

Step4. Then have alternator checked.

 

Sounds fimilar, my 96 was starting good, then went into slow cranking mode for @3 weeks. Sometimes it would start find, other times slow cranking to almost no start. I cleaned the battery terminals, suspected the alternater was not charging the battery and even put a new battery in to see if there was any difference. Still was slow even with a new fresh battery. The problem was the starter was drawing too much amps. This was the orginal starter with 150,000 miles and 14 years old. Replace the starter and no more slow starting problems.