mphilleo

I'm feeling pretty stupid about this one because I've fixed a handful of cars and should probably know better. The other night, I replaced the spark plugs, wires, cap and rotor on my '90 Cherokee (4.0). The plugs, Champion RC9YCs, were gapped properly, I found the FSM and determined the cap and wires are routed correctly and even all my connections under the hood appear correct (you never know, you may bump something loose on a car that's new to you). It may be a factor, but I also replaced the battery with one of the correct size and CCA.

Anyway, like I said, it won't start. When I turn the car on accessories, the voltmeter shows about 9-10.5 so I figured I'd give it a charge for a while. Not sure if I'm whizzing into the wind here, but I'm not sure what I'll try next if that doesn't work. Not to mention, after several attempts, it gave me a nice, loud backfire, probably from flooding.

The only other X-factor I can think of is that I did do this mod:

http://www.jeepforum.com/forum/f46/x...75/index2.html

For what it's worth, here's a couple cell phone pictures of my engine bay (flushing coolant right now) to see if anyone can tell me something isn't right.

xjforfishing

If it was running before you did this, then you changed something....the mod you did shouldn't make any difference...I would look again at everything you did and make sure your plug wire routing is correct, that is the easiest thing to get wrong....coil wire...power to distributor....you will find it and feel stupid, but most of us have done the same thing....good luck...let us know what you found..

orceph

man trying to figure out how to post a question im new here please help

mphilleo

I'm certain you're right. With that in mind, I printed my FSM page and tried a few different configurations for the wires. The reason that I'm a little confused, as these pictures show, is where to start the firing order. I understand the order, but if you compare my rotor (pictured below) with the FSM diagram, they don't match...the brace screws are in different locations. If anyone could help me determine which way to route the wires, that'd be awesome.

The FSM diagram...



...versus my situation, as viewed leaning over the passenger fender:


You can plainly see the cap screws don't match the location on the diagram. I thought I'd be all smart and match up the numbers to the posts when I removed the old cap, but that's what got me my no-start situation.

tys91

so I’m currently working on my 91 jeep Cherokee Laredo 4.0, I’m have a small problem with it starting, i started it this morning and drove to the mall 30 minuets later when i return for the mall to start it, it doesn’t turn over. no engine noise at all, no pistons firing or belts moving nothing. its not my battery because all my electronics work such as my light, sound system ect. i just went and replace the started and still nothing. if I have a buddy twist the ignition and i ark the starter solenoid it fires up like a champ. but as soon as i turn it off and retry it. doesn’t start. any ideas?

xjforfishing

your firing order should be ...1-5-3-6-2-4...you can double check on your manifold...#1 should be the bottom right post...start by running the bottom right wire to #1 and going counter clockwise follow the rest of the firing order...this is the way my 95 (4.0) is configured...hope this works for you

mphilleo

Thanks for the suggestion. I tried it and, again, no luck. I'm not really sure what's going on, but based on your description, this is how I re-set the wires:

xjforfishing

my humble apology...I screwed up...it is clockwise not counter clockwise...don't know what made me say that...must be getting old...very sorry...I know how frustrating this can be....

6......2
3.........4
5.....1

mphilleo

I've already tried that configuration...is it possible that there's something off about my distributor because of the orientation of those screws? It seems like it's just not the same. It could be possible that someone swapped the engine and distributor with something wholly different, so it doesn't use the firing order of the 4.0.

89XJDan

Make sure your timing is on? And I'm assuming you have fuel but no spark?

I just had a no spark issue, and replacing the ignition coil fixed it for me.

mphilleo

I have no idea if my timing is on or not. If I have to replace the ignition coil, that's fine, but I guess it just seems weird to me that the timing would be off, or the ignition coil could crap out at the same time I change my wires, plugs and cap/rotor.

89XJDan

I agree, it would be quite a coincidence. But before mine went out, my idle was a little rough(maybe you did tune up because of a rough idle, just making that assumption.) Not sure if my idle is back to normal now, because I haven't taken it out since I replaced the ignition coil. I'd start with checking your timing(assuming the timing on these motors can even be off.) And if that's on, then take off your ignition coil, and take a volt/ohms meter to it. Check the primary and secondary winding. Should be 1.2-1.7 on the primary, and the secondary is a bit of a toss up. xD Interwebz says in the 4.something k range, Chilton manual says 11.3k-11.5k, and the new one that I just put in, that works, is 7.something k, mine is an '89 with the 4.0. If you don't have a volt/ohms meter, your local O'Reilly's should have one and be happy to help.

mphilleo

Just to clarify, I can post more supporting images, but the reason I'm getting frustrated and puzzled is that my rotor cap doesn't match any available diagram. The screws are in a totally different position and I have no points at 6 o'clock and 12 o'clock. I don't want to sound like a whiner, but I've owned numerous European cars and never had problems orienting the rotor crap...I had figured an American car (albeit with some French) would be a little more simple. Post #4 in this thread illustrates my conundrum.

mphilleo

Ok, well, I've got it solved. I'm experiencing a mixture of anger for wasting an evening but I'm elated the problem is solved. I figured I'd update this for those who may have been following or might need a reference for their own no-start problem.

And boy was it stupid.

The replacement bargain-bin spark plug wires were the culprit. After a dose of contact cleaner on the tips of the spark plugs and the ignition coil, I put the old plug wires (Belden) on and she fired right up. My theory is that the cheapo wires, though they had dielectric grease in the boot to save you trouble, are not joined at the boot and wire. This allowed the electrodes to get slathered in grease and contaminate the contact points, thus preventing spark.

Safe to say, I'll be paying O'Reilly a visit tomorrow.

I want to thank you folks for helping me with the correct firing order. xjforfishing, your 2nd order you gave was correct. I also apologize for getting miffed and acting like a douche.

xjforfishing

oh good...you got it going...that is the main thing....I again apologize for the in-correct info the 1st time....I am a retired mechanic...maybe I should stay that way...lol...