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Unique No Crank Issue


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Or maybe not, but can’t seem to find specific infomation regarding my exact problem.

 

I’ve recently done an entire 93 XJ HO harness swap into my 88 MJ. I plugged the battery up for the first time today, to test all of my systems. Everything seemed to work except the radio ( easy fix) and the starter. I unplugged the fuel pump until I can change out my sender, but that shouldnt affect the starter. It was an auto XJ, so I bridged the NSS park wire together to eliminate that issue. I can hear the starter relay click when I turn the key to crank, and used a screw driver to bridge the solenoid and make sure the starter was good. 12.74 volts at battery. I tested the trigger wire for the starter, and at the crank position it reads 0.85 volts. I know this is the issue, I’ve read it needs to receive 12 volts to operate. Why such a restriction? Someone has also told me the voltage read out at the wire could just be interference from other components. Could it just be a cut wire, or is there another component that could cause this issue? Any help is appreciated, thanks. 

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I would take a look at the connections where you jumped the NSS. 

Although that said, when I had NSS issues, I got no click at all, turn the key and nothing. You might try swapping out the relay if you haven't already, make sure it's getting 12v to its socket, etc. If the relay's triggering (which happens downstream of the NSS) as we can tell from the click, that would indicate an issue with the switched side of it.

You may or may not find this helpful:

http://jeep-manual.ru/index.php?page=376

but you'll want to check all your fuses in the underhood relay box as well. 

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I've replaced the relays and fuses to make absolute sure, but to no avail. I tested the starter, it works so well it tried to start the engine on me, even without a fuel pump, haha. I even took a jumper wire from the solenoid switch wire to the + side of the battery and she cranked with no issues. When I turn the key to the crank position, the coolant gauge maxes out, so I'm pretty sure that's a good sign of the ignition switch being good. As said above, the trigger wire is only getting 0.85 volts, meaning an issue at or past the relay. Testing the relay, it's only receiving about 5 volts. Something is causing a huge restriction. 

 

2 hours ago, Kickin’Chicken said:

How many volts are you getting to the distributor?

 

Non issue, I'm not trying to start the engine, just get it to crank via the ignition switch. 

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Check fuses F10 (40A, if it's there, might not be) and F5 (15A Ignition) in the PDC under the hood. One or the other, depending on your truck options, supplies the constant 12V to the starter relay. Just for grins, have you swapped the starter relay with one of the others in the PDC? Can you feel/hear the starter relay click when you turn the ignition to the start (crank) position? 

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What voltages are you getting at the relay socket?

should be

30: 12V constant

85: continuity to ground

86: triggered 12v (when you hit the switch)

87: should have continuity to ground I think but this is the signal for the starter so if you jump power to it it should crank the engine. 

 

At least that's the standard relay layout. 85 and 86 are the switch circuit that triggers the other one, 30 and 87 can be reversed and still function. 

 

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15 hours ago, gogmorgo said:

I would take a look at the connections where you jumped the NSS. 

Although that said, when I had NSS issues, I got no click at all, turn the key and nothing. You might try swapping out the relay if you haven't already, make sure it's getting 12v to its socket, etc. If the relay's triggering (which happens downstream of the NSS) as we can tell from the click, that would indicate an issue with the switched side of it.

You may or may not find this helpful:

http://jeep-manual.ru/index.php?page=376

but you'll want to check all your fuses in the underhood relay box as well. 

You sir, saved the day. After getting a severe headache looking at wiring diagrams, I found that the starter solenoid runs THROUGH the rear heated window fuse at the PDC. It makes no mention of it on the PDC cover. I removed the fuse because I didn't have a heated rear window, obviously. Plugged it back in and BAM, starter works with the ignition switch like it should. Sorry for the confusion, and thanks for the help, everyone. 

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This sounds similar to an intermittent no crank issue I’m having. Cranks and fires up 90% of the time. When it doesn’t want to start, with the key on, I can jump the starter with a screwdriver and it’ll fire up..and will start normally until the next time it doesn’t want to. Leads in where to begin? Where is the starter relay, what and where is the pdc?


87' XJ Wagoneer I-6 AW4 NP242

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I’ve noticed that when parking, if I make sure to begin firm and intentional when turned the key to off and putting into park, it reduces the chance of the no start. Leads me to think ignition or nss....i cleaned the nss recently...don’t know how to test electricallly though...


87' XJ Wagoneer I-6 AW4 NP242

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3 minutes ago, Kyleinreallife said:

This sounds similar to an intermittent no crank issue I’m having. Cranks and fires up 90% of the time. When it doesn’t want to start, with the key on, I can jump the starter with a screwdriver and it’ll fire up..and will start normally until the next time it doesn’t want to. Leads in where to begin? Where is the starter relay, what and where is the pdc?


87' XJ Wagoneer I-6 AW4 NP242

 

Have you ever tried starting in neutral when it's happened? Probably your NSS needs cleaning.  Common issue especially if you e ton a lot of driving in the wet and filth.

Clean it out, stuff it full of electric-safe grease, and run a bead of silicon around the edge to seal it up when you reassemble. http://bc4x4.com/tech/2010/jeep-neutral-safety-switch-nss/

Even if it's not the issue its a good idea anyway as preventative maintenance. 

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Have you ever tried starting in neutral when it's happened? Probably your NSS needs cleaning.  Common issue especially if you e ton a lot of driving in the wet and filth.
Clean it out, stuff it full of electric-safe grease, and run a bead of silicon around the edge to seal it up when you reassemble. http://bc4x4.com/tech/2010/jeep-neutral-safety-switch-nss/
Even if it's not the issue its a good idea anyway as preventative maintenance. 


Will do, but yea I have tried, won’t start in anything but park when it happens


87' XJ Wagoneer I-6 AW4 NP242
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