'91 Jeep XJ Not Starting ... Short Cranks When Turning the Key

Hi All,

This morning I started my '91 XJ then shut it off. Now it won't start.

I turn the key forward and the motor does one (1) short crank. I turn the key off, and again one (1) short crank, but it sound like a reverse crank.

Here's a short video of what's happening: https://www.flickr.com/photos/126894351@N08/30841188955/in/shares-887585/

The battery is brand new.

This started happening intermittently last week. It would start in neutral, so I thought it might be the neutral safety switch (NSS).

Last night I pulled the NSS and cleaned it out and re-installed. But the problem still persists.

I thought the worst, so I put a breaker bar on the crank shaft. Thankfully the motor turns freely.

I'm thinking it's the starter, but I wanted to ask just in case it something else like the crank shaft position sensor, or a relay, or the ignition switch or ... or ... or ...

Thanks,
Chris

take your sparkplugs out. and see if it cranks. sounds like it cant spin over. like its jammed on something.

I would suggest making sure the cables are free and clear of oxidation at the battery. Make sure the positive terminal to the starter is tight and both ends of the negative side are tight and clean. If using a charger or jumper cables attach the negative cable to a solid place on the motor and the positive of the battery. My guess is bad ground.

Thanks for the responses!

Automechnic077 said:

I would suggest making sure the cables are free and clear of oxidation at the battery ... My guess is bad ground.

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The battery's ground cable is new. I also replaced the positive and negative terminals on both battery cables.

The positive cable could be severely corroded under the insulation. I didn't think of that one.

I will check the positive battery lead, the starter connections and ground connections. If they're all good, I'll yank the starter and have it tested. I'm leaving the ignition switch until I exhaust all my other options.

can you turn the engine over by hand?

90xj06 said:

can you turn the engine over by hand?

Click to expand...

Yes. I put a breaker bar on the crank shaft. Thankfully the motor turns freely.

sounds like starter it bad and binding

90xj06 said:

sounds like starter it bad and binding

Click to expand...

Yeah, that's what I'm thinking, but I'll check all the grounds and connections as suggested to be safe.

If it cranks at all, then the ignition circuit (including NSS) is fine. The problem is either starter motor, wire to the battery, or battery itself. Might want to get the battery tested, they do fail early sometimes.

If you suspect the starter is faulty, you could try giving it a few whacks with a rubber mallet or a dead blow while somebody cranks or vice-versa. Bit of a redneck trick, but I've done it before...

Alternatively, you can do your own bench test at home. Pull your starter and with a pair of jumper cables, connect your negative battery post to the starter case and then connect your positive battery terminal to the large starter stud. Using a plastic handled screwdriver you don't care that much about, jumper the large starter stud and the small starter solenoid stud and observe the starter operation. Again, bit of a redneck trick, but I've used this trick before to confirm a bad starter or solenoid.

I just now got back from having the starter tested. It tested good. I'm about to clean the starter connections and reinstall it.

Then I'll check all the ignition circuit connections that I can ... focusing on the ground connections.

If the problem persists, I'll have the new battery tested.

If the battery is okay, then I guess the ignition switch is next.

I'll post more updates as I learn more.

I wonder if this could be a bad relay? I'm guessing not, since I'm getting some crank.

I appreciate the comments, ideas and suggestions. Keep 'em coming, I'll try them all

-Chris

You can eliminate the ignition circuit (key, nss, and relay) by using a multimeter on the center small post on the solenoid. That post gets the ignition voltage and then causes the solenoid to bridge the two large posts. If it gets (and holds) voltage for as long as the key is held, then ignition circuit is 100%

Another test is bypass the relay with a short piece of wire (youtube has one for the fuel pump relay, same instructions). That will activate the starter solenoid directly. If the motor spins up, then starter circuit is fine, and problem is on the ignition circuit (or relay is bad maybe)

ehall said:

You can eliminate the ignition circuit (key, nss, and relay) by using a multimeter on the center small post on the solenoid. That post gets the ignition voltage and then causes the solenoid to bridge the two large posts. If it gets (and holds) voltage for as long as the key is held, then ignition circuit is 100%

Another test is bypass the relay with a short piece of wire (youtube has one for the fuel pump relay, same instructions). That will activate the starter solenoid directly. If the motor spins up, then starter circuit is fine, and problem is on the ignition circuit (or relay is bad maybe)

Click to expand...

Great info. Thank you!

So, I replaced the starter and cleaned and tightened every connection in the starter circuit, put it all back together and the problem persists.

Even though the starter tested good, I replaced it anyway because whoever previously replaced it stripped the threads on the starter where the shorter bolt screws in. It would not tighten.

I definitely think it's the ignition circuit, specifically the ignition switch. After I completed my work and tried to start it, the ignition switch stuck in the "start" position. I had to manually turn it back.

The story behind this Jeep is, the previous owner used it as a hunting vehicle. The interior was an absolute mess, so he decided to power wash the interior ... including the dash.

I gutted the XJ interior, bedlined it and replaced the damaged interior including the instrument cluster from junkyard parts.

My guess is there's water damage in the steering column and the the ignition switch is the culprit. So I will replace that tomorrow.

Turned out to be the ignition switch on the top of the steering column. I replaced it tonight and so far the Jeep starts every time. Thanks again for all the comments.