nss help

my 91 is not starting, little history it began not starting about 4 months ago, took nss apart, cleaned it, replaced it. started working, now all sudden it wont start again. repeated above steps but no luck. picked up another one from jy, from a 92 repeated steps above and nothing. checked all fuses all are good. all lights, fuel pump, gauges etc. all come on. am i doing something wrong missing something or a way to test the nss. all help is appreciated thank you
buster

So it won't crank? Not starting and not cranking are of course different problems. If it isn't cranking, have you tried jumping the main + and the SOL + at the starter? If the problem is the NSS then it will crank, and if the key is in the RUN position it will start. If it won't crank when jumped, then it is cables, grounds, battery, starter, starter relay, ignition switch.

Try the Crankshaft Positioning Sensor. From the top of the engine, follow the wire on the back of the engine down to the transmission (small, square block). Tap on that with something long (axe-handle, stick, etc.). I've had problems with both the NSS and the CPS...

If that doesn't work, check your fuel pressure on the fuel rail. Sometimes the fuel pump will go out slowly and although it will still make noise when the ignition is turned on, it won't pump enough fuel to start/run. Had this happen too.

Good luck!

I think he means its not cranking. Isn't there a starter relay on a 91?

lawsoncl said:

I think he means its not cranking. Isn't there a starter relay on a 91?

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correct, it will not crank. how can i test to see if it is the nss, in the past(before first cleaning) i could jiggle shifter to start now that doesn't work. could it be cps that is causing problem if so how do i test for that

CPS/CKP is NO START, not NO CRANK. If you can jump the main + to the SOL terminal on the starter, and it cranks, then your problem is MOST likely the NSS.

check to see if you have back-up lights, if you do NSS should be ok. Now, check your ASD relay, and starter relay. Check applicable fuses for a no crank scenario. if all good replace your crank sensor. -B

additional info: reverse lights have not worked in the 3 years i've owned it, also my son told me that when he drove it he had to use two hands to turn the key i've not noticed this but i drive it daily. 8 months ago i tried to repair wobble in steering wheel but the coupler portion is broken not loose bolts i have not gotten a replacement, could my problem be in the column? thanks again buster

i did the nss bypass (by connecting the b&c wires) still will not crank/start. tried to jump the wires on the starter to see if it would crank no luck only sparks. if the starter relay is bad would that keep it from cranking? how difficult is it to replace cps?

If you jumped it at the starter, correctly, and it would not crank, the following are not your problem:

NSS
CPS

You need to go back to the basics:

Charge battery overnight, or 24 hours would be best.

While charging the battery, clean the cable ends--both ends--and check the cables with an ohm meter, resistance should be at zero or near it.

Now that the battery has been fully charged, take it in for a load test.

If the battery passes, and the cables are good, IT MUST CRANK WHEN JUMPING THE WIRES AT THE STARTER. If it will not crank, then the starter is bad.

Once you have the starter cranking when jumped, you know that: battery is good, cables and grounds are good, starter is good. If all of those are good, and it cranks when jumped at the starter, then you can concentrate on testing the starter relay, ignition switch, and possibly back to the NSS.

Without a confirmed good battery, confirmed good cables, and confirmed cranking when jumped at the starter, then everything else you do is just p/ing into the wind.

kj139 said:

Try the Crankshaft Positioning Sensor. From the top of the engine, follow the wire on the back of the engine down to the transmission (small, square block). Tap on that with something long (axe-handle, stick, etc.). I've had problems with both the NSS and the CPS...

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okay went out found cps gave it a whack, nothing,then i held key in the on position with jeep in neutral and rocked it back and forth then put it in park and it started up:clap:. cps? what do you think? thanks

That is NSS...Before I re-did mine, I would have to hold the key on with my left hand and rock the shifter back and forth with my right. It would find the right spot and start.

Now rebuild that NSS and you'll get your reverse lights back too!
http://jeepin.net/index.php?s=nss
Excellent write-up on rebuilding that NSS. -B

kj139 said:

That is NSS...Before I re-did mine, I would have to hold the key on with my left hand and rock the shifter back and forth with my right. It would find the right spot and start.

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boomhauer said:

Now rebuild that NSS and you'll get your reverse lights back too!
http://jeepin.net/index.php?s=nss
Excellent write-up on rebuilding that NSS. -B

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rebuilding the nss was the first thing i did. did not help. i now believe the cps is the problem or a combo of the two but i have hit the cps a couple of times (had to move it) and it started up.

i know that a new cps is the way to go but has anybody had luck with pulling one from the junkyard?

buster cherry said:

rebuilding the nss was the first thing i did. did not help. i now believe the cps is the problem or a combo of the two but i have hit the cps a couple of times (had to move it) and it started up.

i know that a new cps is the way to go but has anybody had luck with pulling one from the junkyard?

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I bought a new one.... like $40 bucks or so. It SUCKS changing them so i only wanted to do it once. Of couse i had to do mine in the woods on the ground!

BTW good info here

Just to be clear, a bad CPS will cause it to crank and not start. A dirty, misadjusted, or broken NSS will cause it to not crank at all.

buster cherry said:

okay went out found cps gave it a whack, nothing,then i held key in the on position with jeep in neutral and rocked it back and forth then put it in park and it started up:clap:. cps? what do you think? thanks

Click to expand...

This is NSS problem just to confirm. This is the piece on the Transmission. If you are 'whacking' a CPS make sure you do not crack off a piece and have it fall down into the abyss.
Rebuilding the NSS is easy, so try it.
The CPS is a little more difficult but not bad if you remove the front driveshaft and use a good length of extentions 1/4" drive to get at the 2 bolts.
As far as Junkyard, i'm against it. One, it'll be a beeyotch to remove and second no gaurantee it will work. They do have different part numbers; for example i have a late model 96 that has alot of 97 electronics on it. My 96 and 97 have different part numbers and are not interchangable. -B