Picked this up 2 weeks ago up in Venice....
1990 5-speed 4x4 XJ in White
Came with 31" BF Goodrich All-Terrain tires, 2 small holes and some mud underneath.



4.0 was running very rough when I bought it. Decided on new plugs and wires, and a fuel filter. Cap and rotor looked fine, just cleaned them up with some sandpaper. Swapped in the new plugs and wires, now it will not start. I am getting spark and fuel. My only other guess would be timing???

I also had an issue with the spark plugs. I work at Advance Auto and decided with the Autolite # 3924. Turns out, they dont fit properly into the head. They seem to be too long, by about 1/2" to 5/8" longer. Ended up replacing with what was in there already, Autolite # 24.

Any suggestions on these 2 major issues here??

 

U might be onto something about the timing. If its off by 1 tooth it often won't start..

good lookin rig!

 

Going to be digging in to it today. I seen that the distibutor has been modified and the tab has been cut off and was flipped around 180 degrees. I wonder what I am going to see on the timing chain and gears

 

How many miles are on it?

 

I want to say in the neighborhood of 150k miles

not 100%, I will look again later, one thing I didnt pay to much attention too

 

silly question, but when you replaced the wires did you put them back on in the corrcet position

 

sure did. I even took them completely off and used a few different repair manuals recommendations and put them in their order and still got nothing....

 

This to me seems like a big problem...

 

After I seen that I was pretty pissed...

I found this article that talks about the tap removal and flipping it around

http://asashop.org/autoinc/feb99/techtotech.htm

 

As far as I know, I think the lifters are bad. After I pulled the head, I check the valves. All looked to be how it should be. I am going to clean out these lifters and change the oil.

 

I bought mine off a girl that couldn't get her's running sort of like yours, I tried fuel filters, cat, tune up, rotor, plugs....still couldn't figure it out.... I emptied the tank, and used a healthy amount of carb cleaner and thats all that was wrong. Sucked up bad gas cause it was sitting. My buddy had the same problem, we dropped the tank and there was a handful of acorns in the tank ??? o_O so maybe something along these lines?

 

from your pictures it looks like a few of the cylinder walls are pretty rough, did you happen to do a compression or leak down test before you tore it down? while its apart it may be time to flex any machine shop connections you have and get the long block freshened up.

 

Yeah already did the compression test, that is why I took off the head. Numbers were really low

 

Got the head back from the machine shop, said it was cracked. I was going to pick up a reman from my work or Clearwater Cylinder Head, but a customer of mine said he had a 4.0 head. Went and picked it up, was a 7120 casting. Only paid $70 for it. Going to throw it on to see what kind of compression I get with this later today.

 

Hey man - this is a really good thread. While I'm sure its no fun for you to have these issues, it benefits everyone out here just by following along your troubleshooting to see how you fix the problem. I will definitely keep up with your build and hope you get her running soon! Good luck!!