no spark engine dies . help ....

so i looked and search and got some ideas from the other threads but non are rally identical to my problem..
i have a 1990 inline six 4x4 limited


i bought this jeep this week with 135k original miles from original owner .. he says its been rebuilt jeep is in flawless shape and adult owned. ok so here is the problem... when you are driving weither it be at running temp or cold it doesnt change.. stopping or going wont change the motor just dies randomly. cps has been replaced with in a month. and the coil about 2 month ago.. so the mchannic told him the computer is bad.. i dont think it is.. its not getting any spark ... somtimes you can drive the jeep a thousand miles on the free way and no problem but go around the block and dies and wont start just cranks.. any ideas? how to check i really wanna get this jeep home its sitting two hours from my house

I have the same thing going on with my 89 inline6 automatic.... crank and no spark... however once i get it running it will stay running i've never had it die on me while i was driving it....


I just replaced the engnition wires, dristributer cap and rotor becuase before when it would crank with no spark, fiddeling wiht the wires/cap would sometimes get it going again...

But now i'm not even sure if i'm getting spark to the disributor.


Does the CPS bug that most jeeps get cuase a no spark?

so as i keep looking into the 20 or so pages of this dying problem. im seeing that people just clean their connectors and just recheck all grounds or they pull the coil up and check the connector underneath the coil and it works fine or perhaps the cps is having an intermitten problem.. i just assume that since a mechanic looked at this thing and gave the guy the run down that he would infact check all these things but assumption is the mother of all f#ck ups.. he did replace the cps and claims to replace the coil but the coil looks old and i never looked at the cps yet.. i bought it and it has not come home yet due to i can afford the trailer to get it here and im hopeing to just go out there and get it running to bring it home..

When it dies, are the fuel injectors going? That'll tell you if its the ign module or coil. If you have a meter, you can measure the tach signal at the diagnostic connector or at the ign module. If you see the voltage jumping there with no spark then the ign module or coil are bad.

You sure the CPS was really replaced?

i was told it was replaced but knowing how some shops work and the look of the coil i would think it was not replaced. and when i bought it i tried starting it and i smell plenty of fuel just wont start.. i didnt really spend any time unplugging stuff and checking everything being it was 10 at night. but i figure for 500 and having a jeep this flawless it was a good deal and the guy i bought it from was very straight up with me..

i personally have not driven it yet ..

sounds like the cps to me. get a meter and check the cps

CPS camshaft position sensor, in distributor, only effects injectors.

CKP crankshaft position sensor on the bellhousing, it is the only sensor that can kill a Renix XJ.

Renix XJ hyper sensitive to electrical issues, in particular the grounds. Grounds at the passenger fenderwell (starter relay ground), the engine block (main ground), the dipstick tube (just because some dipstick SAE dude thought it was cute), and the notorius back-of-head-to-firewall ground. All, with the possible exception of the starter relay ground, are problematic and should be renewed as routine maintenance.

Use a Dremel tool with a wire wheel to clean both surfaces, use some corrosion inhibitor (hardware store paint department) and tighten the connections.

I wish people would come back and post their solutions...these posts are useless without a fix....