98 XJ (Probably a timing issue)
 

Just bought a 98 XJ yesterday and got it pretty cheap cause the previous owner could not fix the timing issue it's having. He said he replaced the timing chain and since then it's been misfiring when you drive it. It's hard to tell if it's actually having trouble starting or not cause I know the battery needs replaced. But when it does, the idle seem slightly rough (I can tell it's not like it's supposed to be). When you drive it, there is substantial loss of power and the more throttle you give it, the worse the misfire and popping is. I checked the basics like firing order and made sure the wires were still in good shape and they are, still need to be replaced though. There is no engine light present at the moment also. (Or it could just be burned out)

I searched through the forums here and people had similar problems but not exactly what I'm having.

Also, I'm not sure if this has anything to do with this problem, but when it's idling, the oil pressure is around 10-15, but when it's driving it stays around 40.
Motor has around 172,xxx miles on it.

It wasn't doing this before the chain was replaced?

He was pretty unclear about why he replaced it to begin with. I asked and he said it just needed replaced. I'm going to check all the basics then I might have to pull the front face off and check the timing chain install to make sure he did it right.

as for oil psi its slightly low at idle not a huge deal for the mileage its actually not that bad perfect @40 while driving

There were a couple times while idling that the "check gauges" light came on and I noticed that the oil psi was around 0. I gave it a little gas to raise the RPM and it went away.

Before going through the effort to pull the timing chain cover to check the PO's installation, you may want to do this:

Check to see if the distributor was properly installed.

Remove the battery negative post connector.

Remove the radiator electric fan.

Remove #1 spark plug.

Remove the distributor cap.

Have a helper hold their finger over #1 spark plug hole while you rotate the crankshaft via the vibration damper bolt (turn clockwise).

Rotate the crank until pressure can be felt pushing out of the plug hole. This is the compression stroke.

Align the index mark on the vibration damper with the "0" mark on the timing chain cover timing marks (see pic). If you go past it, back up the crank and approach it again.

The distributor rotor should be just past the #1 cylinder distributor cap terminal, and you should be able to drop a 3/16" punch down through the camshaft pulse ring plastic ring and down through the alignment hole in the distributor. See pic.

If the rotor is pointing at #6 cylinder, start over and realign the damper timing mark again.

If the rotor is not pointing just past #1 and the punch does not drop through the alignment hole(s), the distributor is out of time or the timing chain cam sprocket/crank socket are not aligned properly.

Check this and get back.

Good luck.

Pics:

Attachment 320492

Attachment 320493

I should have added to the above post...

Check for rotational play in the distributor shaft by rotating the rotor. A slight amount of rotational play is expected.

Apply a side to side force of the shaft via the rotor. You should see no side to side play. If you do, the distributor is worn out. Same with the rotational play, if there's excessive rotational play the oil pump drive gear on the end of the distributor shaft is worn out.

Ok, I'll give that a try when I get home.

I can actually (when grabbing the top of the whole distributor) get it to turn slightly. The one bolt towards the front that holds it to the crank case only holds it so tight, there is play still left in it.

Just trying to cover all bases, but could an o2 sensor or something like that be causing this? If it was, I know there would be a code thrown out. I'll know more when I get ahold of a code reader.

Not likely, 02 sensors have more to do with fuel trim etc, though they do play a part.

Something not explored yet- map sensor. If it's dumping fuel it could be an issue. On the same note, check the tps for smooth voltage increase

There's supposed to be a clamp holding the distributor down. It is not shown in that pic I posted before, but you can see it in this pic.




Attachment 320489

Cover the basics first. VERIFY things as you go and don't get ahead of yourself.

Yeah, before I go tearing into it, I'm probably gonna pull the fuel injectors and such to make sure theres nothing clogging them up. It's been sitting for 4 years the PO said, so theres no telling what stirred up on the drive home. Especially since he probably didn't put fresh gas in it. :wallbash:

I think you have other matters to attend to besides fresh gas.

Attachment 320476

Well yeah I know. Just something else that I might need to look at if the timing chain and stuff isn't whats wrong.