help please does any one know if the engine computer it has 3 will it stop jeep

Engine Computer Control Unit ECU ECM PCM Engine Computer Control Unit ECU ECM PCM ying to see if i put a new one in if i can get spark i have changed cps,no spark coil,cap rotor still nothing wondered if that would fix it

On a '98 it should be considered the PCM, and I'm not a parts changer, and believe it needs to be diagnosed to find out what the fault is. Most DIY'ers think the computer is at fault and it only uses the information it receives to make things work or not allow things to work with the wrong inputs.

iam a little stuped so it dosent have any thing to do with why it wont get spark iam at a loss

That system has to read the crank and cam, then the computer is supposed to engage the auto shut down relay to provide power to several components before they will operate. Check the auto shut down relay and see if it engages during cranking and battery voltage is going through the relay. There are several other things going on at the same time, but it would take several hours to give a class on this over the internet. The grounds can be another issue, if the grounds are not making good contact, the battery power will have no where to go and complete the circuit. Is the coil firing and have a good power or 12volts to it, then the computer will ground the coil momentarily to fire the coil when it is supposed to fire, and you need meters to read this action when it occurs.

where is the auto shut down relay on 98 cherokee

In the fuse/relay box under the hood.

i have all ready done that it turns over but no spark