ZJMAX

OK so here is the story behind my daughters 93 ZJ. Over the past 2 years it has not started 3 times, If put in neutral it would start so figured at some point I would need to change the NSS. Last week it would not start for her after work so I reminded her to try to put it in neutral. She did and it started and she came home. The next day she went to start it and nothing again, tried neutral and still nothing. She took my spare car to get to work and I started looking at it today. Ignition turns on to where the dash has power, fuel pump cycles etc... On her jeep the NSS is just a small sensor/switch on the driver side so I went and grabbed on since it was only $15. Changed it and still nothing, I turned on the headlights and turned the key and the lights did not dim. Next I bypassed the starter at the solenoid and the starter cranks like a champ. I thought that if the key was in the run position and I bypass the starter like that it should fire and run correct? with the key on and me bypassing the the starter it will just crank but not fire. It's hot and my brain is fried and I need a break due to frustration. Am I missing something simple here? Any advice at this point is welcome. Is there another component I should be looking at?

Thanks,
Max

97grand4.0

ASD and STARTER relays?

ZJMAX

I have checked all the relays and I am not getting a signal to the starter from the ignition. Like I said with the ignition turned to the run position even jumping the starter it will just crank not start even though all dash is lit and the fuel pump primes.

Max

97grand4.0

Are you getting 12v to the starter relay coil?

ZJMAX

Sorry I've had to work OT this whole week. I will check a few more things this weekend and post back.

Max

ZJMAX

So I'm not getting signal power to either the starter or fuel injectors. I tested the neutral safety switch and it is grounding when in park and neutral. I am leaning towards the ignition switch. Being that it's only $35 I am thinking of giving it a try. Worst case I will have a spare.

Max

97grand4.0

Ok, you need to be careful here in describing what you find. There is no signal that goes from the starter to the ignition, or the ignition to the starter. Instead, the signal from the ignition switch ..which is just +12Vdc, energizes the coil of the starter RELAY. The relay is located under the hood in the fuse block with a lid on it. It says STARTER. The energized coil is a magnet which then closes the switch in the RELAY and energizes the starter solenoid. If you pull the starter relay, and find the place in the socket with an ohm meter or diagram that goes to the starter solenoid, you can jumper +12vdc to there and it should crank. SO..
IF you find the place in the RELAY socket, you can also check to see if you are getting +12vdc from the ignition switch, to energize the coil.
If this is as it should be, and the RELAY is good ( you can swap it for the asd relay several of them are the same, dont go buy one yet) then it has to crank. This may save you replacing the ignition switch needlessly even if it is only $35. Mine work fine over 200k miles.