seriously, replace the crankshaft position sensor, it's about thirty bucks, i had the EXACT same thing happen. I had just finished putting in my new injectors, and when i plugged the cps sensor plug back in, somehow the metal prongs inside got shoved back,
(but thats not the only way it can go bad so don't rule it out if the connectors good).
The jeep would crank all day long, wouldn't start and had no spark. I replaced it after looking on this forum and it fired right up. The reason why that it does that is because the cps tells the computer where the crankshaft is and when to give the spark. Thus no spark. but first double check that it is indeed plugged in, also check and see if there is anything unplugged (i.e. ignition coil connectors,fuel pump relays etc. ), hate to waste 30$ just cause it isn't plugged in.

 

Its proubly your timing chain, thats what am dealing with right now at the shop, it turns over but wont start, if you have over 200, thousand miles then yeahh its proubly your timing chain,

 

You can easily tell if it is the timing chain, all you have to do is pull the cap off of the distributor and crank it over, if the rotor spins you timing chain is working if not then the chain is broke or the gears teeth are stripped. The CPS is an easy fix and hard to tell because with a no spark issue you have that, the coil, PCM, the disbutor and the this goes on, and even what I found on mine is that the wires going to the coil had been over heated and melted causing a short and you couldn't see this without taking it apart. The best way to fix the issue is to make sure the parts you have work and just go down the list, don't just throw money at it or you will end up with nothing and issue still taunting you.

 

i agree, check all your wires and connections first. then replace the cps

 

I've got the same problem: turns over but won't fire. When the ignition is turned on i've got power but no guages or spark. The battery is good and I can here the fuel pump. Is this definetely a crankshaft sensor? Is this something I can replace myself with basic knowledge and is there any tutorial on doing the work?

-Thanks

 

Dude, get a code scanner and read the code/s. You can buy one for $35. If you have an older Jeep, I believe you can enter into the diagnostic mode w/o a scanner (at least you can on Grand Cherokees, I've done it). It's very unlikely to be the timing chain. Good luck.

Jeepwalker

 

yeah it's pretty easy, its located on the drivers side of the bell housing and held on by two bolts. the wire for it usually goes up the drivers side of the engine near the firewall. you'll just have to get under you jeep to get to it.
For most people who had this problem it has been the cps, i had the same thing thing happen and i replaced it, and it fired right up. as for me i had been doing some work on my jeep and when i plugged it back in the metal prongs inside the connector got bent back so the sensor wasn't actually connected. chances are if you just did some work on your jeep something is still unplugged. heres a pic of the sensor

 

do you have one for yours? and where did you get it?
because like mine most of the older jeeps (pre-90s i think) are renix systems and im almost convinced that testers for renix jeeps don't exist in this universe. but if you've found one i'd love to know where.

 

I have a standard OBDI/II code scanner. Bought from Harbor Freight on sale for like $69 a few years ago. I use it a lot on my Land Rover (figures, right?) and other cars we have. OK, I'm a little ignorant on the Jeeps codes because our Jeep G/C Laredo 1995 I've always entered the diagnostics through the cluster and count the light flashes. You don't need a scanner forthat vehicle. Either way, get the diagnostice code and it'll tell you what to look for.

Read this: http://answers.yahoo.com/question/in...8154452AAfG0KE

The scanner I have is similar to the one in the middle, but a little different as these are newer versions of what I have:http://www.harborfreight.com/catalog...tegory=&q=code

Search on Ebay or Craigslist. You can find cheaper ones. I forget what year your Jeep is. I aplogize if the Jeeps your year are not OBD, I haven't had enough trouble to have figured it out.

Jeepwalker

 

ok, i was thrown off by your 87 xj you have on your profile, yeah 90 and earlier jeeps have renix, so diagnostic computers can be found inside your skull. but yeah he could probably find one for his '98, and it would be a helpful tool to have around.

 

With this particular problem it is not spitting out any codes! I've read about this problem now on numorous sites and noone else has had a code error or chimed back in with what actually cured the problem! HELP

 

Thanks, I ordered the CPS late last night and hope to get it installed sometime next week. I've also read on a few other sites about the faulty design in their connectors. I plan on keeping you all posted!

 

cool, good luck

 

I have been having a similar problem. The jeep would just randomly not start and then start after a few min. I changed the CPS sensor and that didn't fix it. then I changed the Ignition control module and It seemed to fix the problem for a few weeks but then it started up again. But every time I go to check for spark or fuel pressure it starts so I haven't found the problem. the problem with yours could be the ignition coil or the ignition control module.

 

mine also is a 89 had this same **** it was the map sensor next time it dont start tap the map bet it starts