No spark...

[rdx4me]

After finding this site and seeing the many threads concerning Cherokee's that either do not spin over or spin over and don't start I don't feel like such an idiot!

First (as I have seen numerous time) the ignition switch (key) quit turning the engine over. I replaced the switch and still nothing. So like alot of people on this site, I used a push button horn switch to by-pass this problem. So for the past year or so, this is has kept me going...

A few weeks ago, it quit starting entirely but still spins over. Checked the spark coming out of the coil wire, nothing...

Brand new battery, new rotor, distributor cap, plugs & wires, coil, Ignition Control Module...

Anyone have similiar experiences? I know Jeep is a 4 letter word but I've exhausted my vocabulary of all the 4 letter words I know...

Thanks!

RDX

 

[Ed in North Ga.]

looks like you replaced everything...except the CPS.
it tell the ignition the engine is turning over...makes spark

when you replaced the ignition switch, did you do the keyswitch, or the ignition box-AND if you did the box, did you get the right one- they come in both auto and manual models...both need to be set.

 

[XJXJ]

The CPS is usually fine but the connector on the Renix versions blows chunks. Often, simply pull it apart and reconnect and it will carry the timing signal to ECU and start.

BUT, a BIGGER problem IMO is that people come here and don't clearly define if it's a NO crank - NO start, Cranks but NO Start or the especially sinister, Cranks, Starts and immediately dies. I'm not pointing the finger at this thread and you make a good point of noting the difference but it's the same thing over and over, time and time again, and again.

Bypassed ignition switch? Hmm, did you qualify the NSS before doing that? Do you know if the back-up lights work?

Like anything, XJ Jeeps gotta learning curve but they're darn good vehicles once you get your head around the different NO START conditions. Welcome to the jungle!

 

[Ed in North Ga.]

XJXJ, a few years back had a listing for "problems"- it covered everything a person needed to know on XJs, from "my defrost is on, why?" ,Its cranking over,but not starting", to "why dont I have spark while cranking?" Before that, i had a notepad file on the desktop that i could cut and paste answers off of.....I wore out the defrost explanation.

I think the consensus was that if all the problems were listed, there really wouldnt be a need for a true forum with live people to answer questions...but I still miss the "look here first" list. the archives help, but only if you put in the time.

I like your "crank" rant. is it crunk?, did it crank?, are you cranking?. my pop hated that. crank,cranking,crunk. I can still hear him complaining. "its start,starting,started you fool!" and i`d say, but pop, its just now cranking, when its done, it`ll be crunk...i cranked it over, so now its crunk up. LOL.

 

[rockwerks]

just for grins check the connections on teh ballast resistor also, but yes 90 to 1 its the CPS or connector. I finally cut my connector off and soldered on a different one never had problems again

 

[rdx4me]

This afternoon I went out with Budweiser firmly in hand to find this CPS thing.
I have read on this site that I should try unpluggin / re-plugging the connector.

During my time looking for it, I discovered this (disconnected) vacum line that ran parallel to the valve cover to this item on the firewall. The end appeared torn and dry rotted so I cut it off and reattached it to the item in question.

This item had some electrical wire running out of it. I thought "What the hell?"
and decided to give it a try. After 10-15 seconds of cranking, I heard this click sound from inside the dash and it fired right up....

I've started and shut her off about 20 times tonight and each time it will start within 3-5 seconds. Still using the push button but I'm just happy she's running again!

Any clue what this item on the firewall is? Hard to believe this vacum hose would prevent any spark from leaving the coil...

RDX

 

[beav350]

It's the MAP (Manifold Absolute Pressure) sensor, I've heard that it IS needed to run at all, I've never tried w/o though. It should affect injector pulse-width.

 

[rdx4me]

But the MAP will prevent the coil from producing spark just because the vacum hose is disconnected? This is the only thing I changed this afternoon.
Hard to believe!!!

 

[beav350]

Pull the Green elect. plug & if it won't (or will) run then we've both learned something.