I've got an 89 xj tha wont start' this has happenned once before and the mechanic that worked on it said that it was the computer preventing it from starts, he fixed the problem by reseting the computer but now its happenning again. obviously there is something sending a signal to the computer that is preventing it from starting. it turns over so i know its not the starts, ive got a brand new ignition coil, just did a tune up, but there is no spark. all accesories turn on as well so its not the battery. the first time this happenned was about 3-4 months ago. I'm not sure what to do anymore, I'm lost. there is also another array ofr problems that need tending to but they arent going to effect spark.

 

There are a lot of possibilities for lack of spark, but IMHO, one of the most common is the crankshaft position sensor. It fails frequently on the 4.0

Read this thread for more information and details on how to TEST, which should be the next thing you do before looking elsewhere.

http://www.jeepforum.com/forum/f11/c...ailing-639123/

 

last i knew the 89 doesnt have a crank shaft position sensor, but ill check it out. i might be wrong.

 

yes it does mine did this about a year ago he wires had rotted from age and shorted out on the head try checking this out

 

ALL 4.0 engines have a crankshaft position sensor.

It is an extremely common failure. SEARCH and you will find about thirteen bajillion threads on them.

BTW, nice pic freegdr!

 

it's funny, i read that it doesnt have a cps in my haynes manual, and normally you would take the word of a book over the word of the internet. but not so much i guess. I'll check it out in the morning, thanks guys.

 

You have learned your first valuable lesson about Haynes manuals. They blow............

They are generic and IMHO, not that accurate.

Haynes are low on the totem pole in my book. Chiltons are a bit better, but not much.

FACTORY SERVICE Manuals are the absolute best. They are tailored to your year vehicle and you can take to the bank the information that is in them.

Check ebay as often used ones come up. New ones are available, but can be a bit spendy.

But trust us. You DO have a crank sensor. Really..............

 

maybe it cant breath. is the cat clogged?

 

The problem is no spark. Not catalytic converter related.

 

yeaah, its the electrical for sure. only other issue that really could be it is low fuel pressure, but ive fixed that in the past with anew filter, 22 yearsof **** in the gas tank, i drive 80 mile total with a new filter and it clogs up again, but thats not the problem, like i said, no spark.

 

thanks for all the help guys it was the cps, i unplugged it and plugged it back in and it started right up. now i just need to get a new one lol