hi, i have a 89 xj 4.0l auto 4x4 with a start problem! it wont crank with the key but i can hook up a wire from the solinoid to the baterys and it cranks but it wont fire! one day i was driveing and it wa bads cuting out really bad well drove it home and parked it, then i went to start it the next morning it would crank but not fire!so i figured fuel pump so i checked fuel pressue and it was about 35psi! then i figured CPS and replaced it and distributor pickup, cap and rotor, plug wires, and spark plugs, coil, and the starter relay, also the ignition swich (not the key swich) now when you turn the key on the fuel pump or latch relay chaters i replaced the relays still does the same thing! but whil it chaters i get no spark at the coil, but if i pull the relay it gets spark but no fuel! also it i disconect the fuel pump it dont chater but i still get not spark! the only think i can think next it the pcm?

 

well the first issue sounds like a neutral satey switch. the others hum?? get a manual and start checking youre voltages from the pcm. thats a real hard one not being there

 

would the nss cause all the other problems?

 

the nss sends the power from the key to your starter essentially. and also sends power to your reverse lights. and on newer cars tells the computer what gear its in. to control shift points.

the computer sends out voltage to varies to what sensor it goes to. depends on the sensor it either reads the drop in voltage or resistence to that particular sensor/device and in turn it regulates the fuel and spark according to it readings. do you have any check engine lights? and do you know how to retrieve the codes?

edit; theres allot that can cause this issue. you'd need a volt meter to measure all the differant volts and amps. and also test the relays power to make sure its in range. check your grounds and fuses. maybe a simple issue. but finding it is the hard part. ill try to see if i can get a wiring diagram??

and here it is http://jeepgarage.free.fr/OWN/wiring%20diagrams.pdf

 

no i have no check engine light on

 

check your ignition control module it controls both fuel and spark

 

You say that you replaced your Starter Relay and Ignition Switch?


I would try testing your Ignition Switch first.

To do this; turn your Heater Fan "on" and then turn your Ignition Switch to "start", as if to start it. The Fan should turn off when your vehicle tries to crank. If it does not, that would mean you have a bad Ignition Switch.

You could still have a bad Starter Relay... you could swap it out with the A/C Relay to see what happens?


It kinda sounds like your NSS is acting up. However, i have to disagree with djritter's post though... i just can't see the NSS from keeping the Fump from operating, and if was was bad, you couldn't even get it to turn over at all. I honestly don't know from here besides, this is only my opinion.

I don't know of any other easy way to check the NSS, except the "turn, push and jiggle" trick.



Hope that these suggestions help.

Keep us posted!!!



edit: as i was typing this post, djritter added the idea on the Ignition Control Module... this i too will check into!

 

Ignition Control Module... not much in the Chilton book, anything online?

 

i never said the nss had anything to do with fuel pump. check the link for the wire diagram i posted look under 6 cylinder engine bottom left. theres allot that "could" be wrong with this xj

 

well i tested the modual that the coil sits on and it is good (i took to to oreilys to test it) its weird when i turn the key on the b+ latch really chatter! but i get fuel pressure but no spark now if i pull the B+latch realay i loose pressure but get spark

 

wow odd im gonna study the wiring

 

i apricaite it man im gonna test all the wires for the b+latch relay

 

ok ive got it narrowed down to 4 things cam sensor,crank sensor, b+latch relay and computer. now you replaced the cps crank so its not that. its not the stator/pickup (cam sensor) you replaced it so now its either the b+ latch relay or computer. the computer sends power to the cam sensor and crank and send the voltag back to the computer giving it a ignition signal the computer then send power to the b+ relay. check pin 1 (red wire) on the b+ latch relay it has a fusible link should have power if its faulty may jump or none at all. hope this helps im outta ideas.

 

I had similair situation o 97 jeep xj first time it was a plate under distirbitor cap and rotor ( I believe it was refered to as butterfly) then second time it was starter relay ( 10.00 item ) in pdu under hood I got replaced at O riely.

Hope this helps

 

have you done any welding on it latly if so and u didnt unhook ur batt ur computer is gone i had to replace mine for tht reason i got mine for like 150 buck i forgot where and then i had to sent my old one back. umm check ur crank sensor too it is located on the top of ur bell housing if u look from the top of ur motor u should see it there is a couple of wires running to it and 2 lil bolts easy to cahnge from under the jeep...mine was diff it wouldnt start even with the batt hokked right to the coil and it had no spark in ignition or the coil so i think tht ur prob is probly the crank sensor... good luck id change the crank sensor first cause it is way cheaper....then if no luck then do the pcm....