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1998 Jeep Cherokee has ignition system problem.
So i have a 98 Cherokee, that much you know. Not long ago the check engine light came on while i was driving so i went to an Autozone and had them check the code. They said the code was from the CamShaft position sensor. Theres only one problem. I have a 98 and my Haynes manual only lists a Cam Pos Sensor for 2000 or newer cherokee's.
but even then it was running fine.
now it wont start. I getting what i think is good fuel pressure across the fuel bar (30- 40 psi).
i checked the spark and its not sending a spark past the ignition coil, but the coil isnt bad. I checked the input voltage and i have voltage coming into the ignition coil. so on the random chance the coil was bad i went and picked one up and installed it. Still no spark. so i need some help.
Something is preventing the coil from sparkin my plugs.
but even then it was running fine.
now it wont start. I getting what i think is good fuel pressure across the fuel bar (30- 40 psi).
i checked the spark and its not sending a spark past the ignition coil, but the coil isnt bad. I checked the input voltage and i have voltage coming into the ignition coil. so on the random chance the coil was bad i went and picked one up and installed it. Still no spark. so i need some help.
Something is preventing the coil from sparkin my plugs.

CF Veteran



Joined: Apr 2009
Posts: 18,786
Likes: 14
From: CT.
Year: 88
Model: Comanche (MJ)
Engine: 4.0 HO
no spark ok good lead. does it have a signal to the injectors? if not thats the crank sensor located on the top of the bellhousing on the driverside. It's pretty common.
how do i check for a signal to the injectors?
I have a Fluke meter and im pretty good with electronics, but i dont want to cost myself more money because i did something stupid.
And if i find that i dont have a signal, how do i check the crank sensor to see if its faulty or not
I have a Fluke meter and im pretty good with electronics, but i dont want to cost myself more money because i did something stupid.
And if i find that i dont have a signal, how do i check the crank sensor to see if its faulty or not
CF Veteran
Joined: Oct 2008
Posts: 2,543
Likes: 5
From: Stafford,VA
Year: 1998
Model: Cherokee
Engine: 4.0
ive never had to mess with a CPS sensor but id imagine it's a magnetic swith open/closed by the turning of the flywheel. It should be able to be checked while cranking with a OHM meter. Some one will correct me if im wrong......
you can do a real quick test to see if the injectors are working with some common stuff around the house i homemade a noid light using a xmas tree light bulb. i pulled it out of the plastic holder straightened out the wires on the light and solderd on longer wires then i simply removed the connector to the fuel injector and touched the wires to the terminals on the connector and have a buddy crank it over you should see the bulb flash rapidly if your getting signal
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The cam sensor is in the bottom of the distributor... below the rotor. It's a Hall-effect device that is way before the coil. The cam sensor tells the PCM where #1 cylinder is.
It looks like this:

EDIT: I'm not saying this is the problem. I'm trying to help you understand how it works.
Last edited by solderjunkie; Apr 19, 2009 at 06:29 PM.
CF Veteran



Joined: Apr 2009
Posts: 18,786
Likes: 14
From: CT.
Year: 88
Model: Comanche (MJ)
Engine: 4.0 HO
how do i check for a signal to the injectors?
I have a Fluke meter and im pretty good with electronics, but i dont want to cost myself more money because i did something stupid.
And if i find that i dont have a signal, how do i check the crank sensor to see if its faulty or not
I have a Fluke meter and im pretty good with electronics, but i dont want to cost myself more money because i did something stupid.
And if i find that i dont have a signal, how do i check the crank sensor to see if its faulty or not
I have a 98 also and the CPS is what i had to replace. good diagram by the way.... would have been good info before i bought a coil that did not fix the problem. the Cam Position Sensor is a cheaper and WAY easier part to replace than the Crank Position Sensor
have a problem on my 98 with no spark getting to the coil. replaced the coil and it started and ran fine that same night. let it sit for three days and now no spark to the coil again.




