Jeep Wont Start !! Please Help

daveb

New member
1044721

I have 2 Cherokees a" 99, and an old "88... I took the 1988 4.0 6cly. four wheeling just 1 time.. it sat for the weekend, then on mon. morning would not start.. no spark..it seems.. put new rotor ,cap, wires.. still no start.. then replaced ( 2x) ign. control modual ..coil tested good..it started.. then after a rain.. would not start.. then bought new coil.. it ran for a couple weeks.. then stalled after a few miles one morning.. had it towed.. was in shop for 2 weeks.. they ran comp. test, and checks.. everything was ok.. including the CPS ..it started for them .. and they dont know why..Now again.. after some damp weather..it wont start ..

Then i came here.. looked up some old messages. tried MudderChucks idea .. i changed the ignition switch.. still nothing.. been cleaning wires .. etc.. no good..any other suggestions? I need help.. Thank You s.. Dave B[addsig]
 

1044723

welcome to the board man! looks like you've managed to land your first post in the WRONG FORUM! haha... that's cool. from the sounds of it, it may be a computer module or something... [addsig]
 
1044749

Ignition switch is pretty far down on the list of things to check (next to last). Wasn´t talking about the part with the key, but the inards where contact is made, if the key is wiggled and they work, it´s time for a closer look (but this is rare). But your problem really sounds like moisture somewhere where it shouldn´t be. Something easy to check and often overlooked, is moisture below the mounting plate in the distributor. Many of the distributors for your 88 have an air vent on top that lets more water in, than lets air out (compressed air squirted under the plate will often blow out sand, water and whatnot). the distributors leak anyway. Another thing to check is the coil, starting relay, connectors and junction block on the right front fender well, inside the engine compartment. If MOISTURE gets in the CONNECTIONS it will really mess things up. Could be a coil to distributor high voltage cable, leaks and cracks ar often hard to find, along with loose or leaky cable boots. Hooking the motor up to an old fashioned Sun ignition analyzer will find a cable leak fast. Another way is to hook the old timing light up to a suspect cable, aim it at a handy dark spot and you can see weak and intermittant ignition impulses. Good hunting. Don´t forget to do a real good inspection of the vacumn lines, they have a tendancy to fall off or wear through after bumps and shakes. Might not be ignition at all.[addsig]
 
1044751

thanks for your Quick replys. Had to wait 2 weeks for the mechanic..I know i goofed in the posting.. dont know how to fix that either. anyway...do you or anyone know exactly what senors or relays effect starting..there are four relays near the coil..(square blue)..i here them make a little clicking noise.. but that could be normal. Reading and following procedures form my haines book, isnt helping me much.What about the pickup coil? Cant see where in wiring diagrams, that the pick-up coil is involved in ths starting.

The ign, switch was only 10 bucks. was worth a shot. a pain in the butt. though i can eliminate that issue. When to i concede that it might be the engine control unit (ECU) ?

Was out there in dark last night , having wife crank it over. to see if i saw any sparks jumping around. saw nothing strange . today is another day. the sun is shining , maybe it will start.

Thanks again

Daveb[addsig]
 

1044765

The guts of the ignition system and the computer, on the early models are pretty primative and durable, I can´t remember anybody that every changed any of it, that cured the problem (of course anything is possible). It might run bad, but they usually started and ran somewhat. Found many worn cables (wires) corroded connections and such, water where it shouldn´t be etc. Thought I had a bad starter relay, silver looking box by the ign. coil and relay rack, opened it up and found it was full of mud and water (it´s also on the list of things to look at for ignition problems). Found the cables under the carpeting that were worn through and shorting through the moisture in the carpet. I´ve broken a few position sensors, but never replaced a bad one on the early models. When checking the ignition and such, it´s advizable to use high impedance test equip. (something designed for electronics). Did see one bad computer module, guy hooked up a set of jumper cables back words and pretty much fried everything. Good luck and good hunting. Let us know what the final solution turns out to be, this board is, a learning exsperiance, for most everybody here. Nobodys seen it all.
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