I have an 89 4.0 that is not getting spark but reads 300 rpm koeo.
Doesanybody know y?

 

I finally just fixed my no start/no spark condition. It's probably the Crankshaft Positioning Sensor, which is what everybody told me to check and it turned out to be the problem. But when it crapped out it caused a whole bunch of stuff to go. It blew out the coil Camshaft Positioning Sensor. When it went and I lost spark, I was driving home and it caused a bad backfire which blew out the muffler. I got all new components and it started right up. If you have any questions, let me know, I might be able to help you.

 

If your tach is reading weird prolly the coil... Most cars the tach is read off of the coil.. I would try that first

 

I would check your cps,icm which is located under the coil,and the coil,if you have a multi meter you can check all them before you replace them.

 

Ok thanks for the info but allow me to clarify...
I saw these readings using a Scan-tool.
I am mildly expierienced but am not sure as to how i would check the CKP.
Can someone please ellaborate? Pics possibly?

 

http://fototime.com/78EA763821BA137/standard.jpg Use a multimeter to test the resistance between points B and C. It should have no resistance whatsoever (zero resistance). If there is resistance it needs replacement. The multimeter should be set to 10k-20k.

 

http://www.jeepforum.com/forum/f11/c...-start-824242/

 

Thank you verymuch for the helpful info.I will not be able to check this out for a week or so but i will let you guys know how it turns out.