I have a 96 xj 171k oil pressure is at 0 when not moving but goes up while driving. Cylinders 1 and 6 at about 70 -/+ 5 compression. all others ok torque converter bolts were loose so tighten some vibes gone but still knocks. Get a weird ticking scratching sometimes tranny area. Knock sounds like coming from tranny rear motor area. Unplugging injector 6 makes noise louder. Going to replace motor kind of don't want to take the risk of used what else can i do to diagnose. Also burning oil.

 

You are going to replace the motor? Sounds like you have a problem with #6 piston among other things.

 

I think I'm going to double check flexplate before anything cuz id rather not do a bunch of work and spend a bunch of money for nothing. As for other stuff my injectors need cleaning. Not correct fuel mixture could cause low compression correct??

 

No, it's a mechanical problem. Rings, valves or some of both. Common way to determine which is to dump a few Tsb of oil in the cylinder and repeat the test. If pressure rises substantially it's the rings.

Good idea to check the flexplate bolts.
I can tell you mine had a tick from the rear of the motor that got worse when I unplugged injector #6. Found #6 piston broken upon disassembly.

 

Okay ilk try the oil in the cylinder. my thing is i just want to pin point it so i can fix the darn thing. I really hate the whole used motor swap thing. Could i get a master rebuild kit or just redo rings?

 

I've got a knock in my 93's 2.5 that I'm pretty sure is my rod bearings going bad. Unplugging cylinder 4 injector made it go away. Can't be the flexplate since it's married to an AX-5 manual....

 

See unplugging injectors doesn't make it go away

 

Okay, I must've missed that somewhere....Sorry. I was along the line of thought it could be like mine.

 

Have you did a complete engine overhaul before? If not you could be throwing away a lot of money in machine work block, head, crank, balancing....IF....they are good to machine. Then a master overhaul kit with all the proper tools there are quite to do this job then the know how to get the job done.

You do know that all the block work has to be done before you ever order any parts

Just a few small problems during the build can trash an engine as soon as startup or a few thousand mi. till it goes.

 

That's why ill buy a use motor for 300 and just throw it in