OK, this is killing me. What is wrong with my YJ!?!

[92 Green YJ]

OK guys, I am at my wits end with this. a bit of background:
Last week i was driving on the highway when it just died on me. it kind of sputtered a bit, then it surged, then boom, dead in the water. i tried starting it again and nothing. occasionaly it would fire, run for about 30 seconds, then die again. got it home by flat towing it then it sat for a few days until i could check out the problem.

Now a few days ago i went in and replaced the catalytic converter, new spark plugs, new cap and rotor. It fired right up and seemed to be running ok.

Now, yesterday we hit the highway to go get something, and it missed a cylinder three times, at least thats what it sounded like to me. we pulled over, checked it, everything looked ok so we kept going. got back home from where we were going just fine. then went to go out again. we got 13 blocks from the house when it died again. we pulled into a parking lot and started fiddling. we cant see anything obviously wrong. the real kicker is we came back for it about an hour later to strap it home, and it fired right up and i drove it home.

I am at my wits end here! I tried pulling trouble codes, nothing came up. its getting good fuel pressure, its getting spark, though im not sure its as strong as it should be.

Now the plot thickens. Just replaced the coil and wires. turns out they were shot and apparently i've been running on 5 cylinders for a while. So we get it all replaced, i went and put dielectric grease and cleaned every single electrical connection i could find. I pulled the valve cover,cleaned that up and put it on with a new gasket (the old gasket was shot) and replaced the fuel filter

So we fire it up and first off it sounds like ***!! I have a crack in my header, i know that, but driving it around the block to park it it has ZERO power!

Now i am not the kind of person by far to give up and go to a shop so I will figure this out. I just don't know what else to look at at this point. I've tried every logical thing i could think of!what else should i be looking at here?

[goodtimes]

Start by double checking your plug wires...are they tight, not burned (laying against the header), and going to the correct cylinder? If you wait until it is dark out, fire it up, you will be able to see any electrical shorts that are on the secondary side of the coil and external to the engine (You can see the spark literally crawl out from under plug wire boots and to ground....kinda impressive actually....saw it on my mothers old bronco....spark would occasionally crawl out from under a plug wire on the cap and jump to ground). This is not a replacement for other tests, but it is quick and easy and may help find intermittant secondary spark issues.

Check the timing.

What does the inside of the cap look like? You should see where the rotor contacts the lug for each wire. There should be no reddish residue on anything, and you shouldn't have any pits or black marks on the lugs or rotor tip (since you just replaced them).

Make sure the primary side of the coil is wired correctly and the connections are tight (I spent 2 days troubleshooting a similar symptoms to yours on a '72 chevy blazer only to find a loose connection on the primary side of the coil).

[fwak]

Are you burning through fuel rapidly or at a normal rate...are you carbed or EFI?

[92 Green YJ]

its a fuel intected 4.0L
So far I have replaced:
Catalytic converter
Cap, rotor, Plug wires, spark plugs
Ignition Coil
Negative battery cable
Fuel Filter
I have also cleaned and used Di-electric grease on just about every plug and electrical connection i could find under the hood and under the YJ

Now it sounds like it is running smooth, however, it is loud as hell from the crack in the header and it is idling erratically when in gear. I am also experiencing no power under acceleration.

today I am going to pull the header and weld up the crack, and check the CPS while i am in there

[D4x4Fish]

it kinda sounds like your "crankshaft position switch"

If it happens again locate the plug (back of engine top of bell housen) unplug the cord wait a few seconds and plug back in. If your jeep starts up, replace the senor.

[92 Green YJ]

ok, I win the official De, de, de
retarded award of the day!
turns out somehow the number 4 and number three plug wires were reversed

[steelman]

ok, I win the official De, de, de
retarded award of the day!
turns out somehow the number 4 and number three plug wires were reversed

And here I just thought it was the square headlights! :gun: :zip: :wink:

[92 Green YJ]

Ok, Its NOT FIXED!!! I got a grand total of 6 blocks and it died on me again!!!! I had to friggin push it into a parallell parking spot!! What a PITA!!

[killwhytey07]

I have the same sort of thing happen to my YJ somtimes, every once in a while i'll go to start it and it will just refuse completely, wait a couple hours and it'll fire right up... no one can give me a real reason for it, so I've learned to have a back up plan. I wish I could give you the miracle fix, but I'm waiting for it too haha

[D4x4Fish]

it kinda sounds like your "crankshaft position switch"

If it happens again locate the plug (back of engine top of bell housen) unplug the cord wait a few seconds and plug back in. If your jeep starts up, replace the senor.

Try this

[92 Green YJ]

i have a new CPS on order. should be here tomorow

[fwak]

Yea I was gunna say sounds like your CPS....mine did the same jank a while back (3 weeks)....and I did the same thing you did and then I checked my codes and what not...turns out TPS....let me know how it goes I may be able to contomplate some other ideas

[92 Green YJ]

I do beleive its fixed! I got and installed the new CPS yesterday. Fired it up, she ran for about two minutes in park, then stalled. But this time she fired right back up. I then drove it around for about a half an hour, going up hills and such and she was running strong and did not stall out anymore. Thank you everyone for all the help

[fwak]

Make sure you disco the battery and let it sit for like 15 minutes like that so the comp resets