ok Why is it that my (sorry its not about atvs) 88' jeep cherokee sometimes has spark, and other times doesnt?!?!?! I try to start it sometimes...and it dont start....and other times it fires right up? the computer has been replaced twice already! can anyone help?

 

coils may be dirty and/or loose... have you changed sparkplugs or wires?

 

Its your crank sensor I have seen it many many times on the Cherokee.

 

I had a toyota once that i had to change the distributer cap very often due to the cap going bad, I i'd change your cap and rotor and you should be good to go .

 

ignition module, coils, crank position sensor, wires, distributor.... take your pick. make sure your grounds are all connected and are making a clean contact. and make sure your not getting any more then 12V to the computer or you'll fry it, if that keeps happening look for a short in a wire. usually, if a sensor or the ignition module goes out it'll go out all at once and wont work intermittently. which leads me to believe its a broken or shorted wire somewhere or a bad ground. we get cars in my shop all the time that people cant figure out whats wrong with the symtoms you explain and we check the ground straps and wires for shorts or breaks first, and 9 times out of 10 thats the problem. check all that and let me know if you find anything. and if not i can help ya through it if you'd like...

 

If your symptoms are when you drive it and then let it set and go out and try to start it and it has no fire and then go out and try it again a hour or two later and it fires right up (sometimes) its your crank sensor. I just replaced one last month for a guy on his 88 Jeep Cherokee. The sensor is on the transmission bell housing on the left side up toward the top. There are 2 or 3 different sensor so you might want to take yours off and take it with you to make sure they give you the right one at the parts store. 9 times out of 10 the crank sensor is your problem on the Cherokees. Let us know what fixes it for you.

 

So my dad came over from faribault to check it out....he unplugged one of the wires to the injectors....and it fired right up...

 

I thought it wasn't getting any spark? The injectors should not have any thing to do with it not having spark.

 

I know the injectors have nothing to do with it....but it worked...and it wasnt getting spark...that was verified by two different people...

 

The one I fixed last month his symptoms was he could drive it to town get out and do what ever he needed get back in and it would not start (because it had no spark). Let it sit for awhile or over night and get back in the next morning and it would fire right up.