WTF is wrong with my Jeep?

[ci5ic]

Hey, I need some help with my Jeep.

It was running fine the other day, and I decided to do a tune-up on it. I don't know when the last time was that it had one. Anyways, I did air-filter, spark plugs, cap & rotor, and plug wires.

Originally, when I finished the tune-up, I started it up, and it was running really rough. I didn't even want to drive it. Check my spark plug wires, and found that they were in the wrong order for some weird reason (I swapped them over one at a time from the old cap). Anyways, checked my Chiltons manual, and got 'em all set up in the right order. Then the jeep wouldn't start at all. Then realized they were all off by one post, so I moved 'em again. Still, the jeep runs really rough. A friend of mine took a pic of his cap and e-mailed it to me, and it looked like all the wires were off by one post again, so I moved 'em again. Now the engine still won't start.

I'm completely confused. I thought it might be the dizzy got rotated a bit and caused my timing to be off, but then I found out that you can't adjust the timing by rotating the distro...

I'm totally stuck, any ideas?

Oh yeah, it's a 1989 4.0L Cherokee Limited (inline 6)

[CodFish]

Are you sure about not being able to turn the distributer to change the timing becasue i knoe on my 1989 i could. I had a problem like you except on mine the fuel pump was bad...... but that doesnt sound like it is bad on your car becasue after awhile it would build up enough fuel pressure and start. You should try your old plug wires.... maybe your new ones are bad.

[ci5ic]

Originally posted by CodFish
Are you sure about not being able to turn the distributer to change the timing becasue i knoe on my 1989 i could. I had a problem like you except on mine the fuel pump was bad...... but that doesnt sound like it is bad on your car becasue after awhile it would build up enough fuel pressure and start. You should try your old plug wires.... maybe your new ones are bad.

I checked all the wires, each one is getting spark. I haven't verified that I can't turn the dizzy, that's just what a friend of mine told me who is pretty knowledgable about the 89 4.0 cherokee. He's stumped too though... Pretty sure it's not the fuel pump, like I said, the Jeep ran fine before I did the tune-up, so the only thing I can think of is the firing order, but I've checked soooo many times, and I'm sure the order is right.

The dizzy is not loose, I tried to turn it, and it is tight, so I don't think I just accidentally bumped it and it turned or anything...

[CodFish]

You should try putting your old plug wires and plugs back in... maybe you just got a bad set.. otherwise i dont know. Hey.. does your cherokee have an engine knock at all... i just wanted to know because it seems common with the late 80's cherokees.

[ci5ic]

Okay, a little more info...

My jeep has a power-train control module (PCM) which automatically controls spark timing, which is why it's not adjustable via the distributor...

As far as knock goes, I don't normally have it, but it knocks like crazy after the failed tune-up attempt...

I know for a fact that all the wires are good because, while the engine was running, I removed each one from the cap individually, and for each one, the engine would bog down.

I double checked to make sure I got the cap on the dizzy correctly, and it's keyed, so there's no way I could put it on 180° off.

I also checked to make sure that the rotor was seated properly, which it is.

Only thing I can think of at this point is that maybe there is a vacuum leak somewhere or something...

[CodFish]

I dont know what to tell you.... It could be a vaccum leak but im not sure.... You should see if you could get your hands on one of those diagnostic plug ins..... i was told that they dont make them for our year but im positive they do.... You should be happy you dont have a knock like me though... it really sucks.... Do you think it could have anything to do with the coil????? im not sure just a guess.

[Journeyman]

sup, check this out , I tuned up last year and had bad ideling and start up. I noticed a small slice in one of the plug wires and it was arking off the block instead of in the combustion chamber. so it was missing bad , fixed that and i was good to go. Also double chech your gap, mabe when you installed them you might be off.

[jif1]

When the tdc (top dead center)sensor goes bad the motor crank over but will not start. The tdc controls your spark. Its located 0n the top of the bellhousing. It cost about $30. to test it unplug try to start it, then plug it back up.

[94XJSport]

Disconnect your battery and let the computer lose all logic. Make sure your wires are in the correct firing order and wired to the correct plugs. Reconnect your battery and start up the engine. What happens sometimes is the ecu is looking for a reference to TDC if your plug wires are off by 1 spot, the computer will actually try to compensate. It sounds like this is what happened and it learned that position. You can remove the distributor hold down bolt and crank the engine while moving the distributor clockwise and it will start up. I did this with several Jeeps and it works.

[kevin888]

where is the fuel pump on the jeep 4cyl wrangler. is that #1 plug hard to get out or what. thanks kevin

[rmousir]

have you checked your cap to make sure that it is not screwy. I got a cap and it was cracked. i would go back to the old stuff and see if it runs good. I think you have your wires crossed. no pun intended.

[trekpsycho]

I don't know if you have fixed your problem or not, but when checking the firing order on the distributor, did u check to make sure that you were wiring it up on the correct rotation