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Engine won't crank. Not the battery. New starter
- Thread starter NepaXJ
- Start date
- Location
- Minneapolis, MN
You should start with some basic preventative maintenance and troubleshooting, right ? Are all the tune-up parts fresh ?
Random stalling should make one suspect a faulty Crankshaft Position Sensor (CPS). The CPS should be tested.
As a test, bypass the Neutral Safety Switch (NSS).
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. 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 to.
Test the output at the alternator with your Volts/Ohms Multi-Meter . You should be measuring 13.8-14.4 volts. Load testing the alternator is still recommended.
Place your Volts/Ohms 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)
Random stalling should make one suspect a faulty Crankshaft Position Sensor (CPS). The CPS should be tested.
As a test, bypass the Neutral Safety Switch (NSS).
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. 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 to.
Test the output at the alternator with your Volts/Ohms Multi-Meter . You should be measuring 13.8-14.4 volts. Load testing the alternator is still recommended.
Place your Volts/Ohms 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)
Last edited:
lawsoncl
NAXJA Forum User
- Location
- North Idaho
If it cranks when you put it in neutral, the neutral safeyy sensor probably needs cleaned up. Do a search, there are plenty of writeups for it.
Jim Malcolm
NAXJA Forum User
- Location
- PA
This issue is not related to the NSS. Not saying the NSS isn't part of your problem, but you have another problem as well. I suspect the ignition switch or related wiring.
8Mud
NAXJA Forum User
- Location
- Central Germany
What year? There is a TSB for the mid nineties models to tighten the screw at the end of the PDC (bus). A wire goes from the positive battery terminal to the PDC, the screw to tighten is under a small cover on the battery end of the PDC.
Waynerd
NAXJA Forum User
- Location
- North Canaan, Connecticut
Not sure about the XJ but my old ZJ one time wouldn’t crank and it was the fuel pump. Apparently when there was no fuel it would kill the asd relay.
br1anstorm
NAXJA Forum User
- Location
- United Kingdom
I had a similar problem on my 93 XJ.
I have always had a slightly dodgy NSS. Sometimes it wouldn't start when in Park. Shifting to Neutral usually enabled it to start normally.
When I suffered more frequent no-start issues, I thought it was a faulty Crankshaft Position Sensor (CPS), so I replaced it. No improvement.
The problem turned out to be a faulty - or failed - ignition coil. That does produce symptoms such as those you describe (occasional loss of power, and hard-starting). So check the coil for decent spark. It's also easy and cheap to replace it.
I have always had a slightly dodgy NSS. Sometimes it wouldn't start when in Park. Shifting to Neutral usually enabled it to start normally.
When I suffered more frequent no-start issues, I thought it was a faulty Crankshaft Position Sensor (CPS), so I replaced it. No improvement.
The problem turned out to be a faulty - or failed - ignition coil. That does produce symptoms such as those you describe (occasional loss of power, and hard-starting). So check the coil for decent spark. It's also easy and cheap to replace it.
A few more details are needed too.
What exactly happens when you crank? Nothing? Do you hear a "click" or "clank"?
On the end of your starter are 3 terminal posts. Two large, one small. One large is you battery +. The other large feeds power to the starter motor. The small get 12v from your starter circuit to energize the solenoid.
If you crawl under where your starter is located, you can see them all. I attach a jumper wire (mine is 4 ft with alligator clips) to the small post that then run up the bay to touch to my + battery post , key off, in park, ebrake on, wheels chocked. Starter should crank (engine will NOT start). This bypasses every other junction, switch, relay etc. This can confirm or deny the issue is your starter, your battery, or battery connections. You can them work your way upstream.
NSS is my guess based on your post. There are tons of post and YT vids on how to bypass the NSS.
Good luck.
What exactly happens when you crank? Nothing? Do you hear a "click" or "clank"?
On the end of your starter are 3 terminal posts. Two large, one small. One large is you battery +. The other large feeds power to the starter motor. The small get 12v from your starter circuit to energize the solenoid.
If you crawl under where your starter is located, you can see them all. I attach a jumper wire (mine is 4 ft with alligator clips) to the small post that then run up the bay to touch to my + battery post , key off, in park, ebrake on, wheels chocked. Starter should crank (engine will NOT start). This bypasses every other junction, switch, relay etc. This can confirm or deny the issue is your starter, your battery, or battery connections. You can them work your way upstream.
NSS is my guess based on your post. There are tons of post and YT vids on how to bypass the NSS.
Good luck.
