Hello everyone, I'm new to the forums and just recently bought my first jeep. 2000 Cherokee 4.0 4wd
I figured it would be easy to fix but it isn't cooperating, so i'll list whats wrong with it first.
1.Cylinder 6 is not firing, even after I replaced the coil pack and all of the plugs. plug looks wet as far as I can tell but doesn't look like its been going off.
2. CEL is on but My first guess would be the cut wires on the rear o2 sensor, btw it has about a 1inch peace of pipe on it with the sensor in the end of it ( is that supposed to be there?
3.There is a wicked creak noise coming from the front end right around the two bars connected by a shock.

Background: I needed a new vehicle bad ( as my car needs a new engine) and someone said they found a jeep for me for a good price. my buddy looked it over and going off of what the guy told us it sounded like a sold vehicle.
The engine has been changed, the head doesn't have the bolt holes to hold to coil pack so i have no idea what year the engine is. it only has 2 O2 sensors, the two on the manifold have been plugged off like they where never there.
I have mostly worked on imports (cars) so this jeep is almost completely new to me, any help would be greatly appreciated. i have some pictures if that would help any.

Thank you for your time

 

I can't help with the other stuff, but...

The 2000 originally had two exhaust configurations, CA emissions and EPA (aka "49-state") emissions.

CA emissions had four O2 sensors and used the extra O2 sensor bungs in the manifold.

The EPA version only had two O2 sensors, one under the firewall in the front and one behind the main cat in the rear. So for the EPA version, the manifold still had the bungs for the extra O2 sensors, but they were plugged from the factory because they weren't needed.

You can look at the sticker on the firewall in front of the driver to see which version your Jeep originally had. My guess is that it was EPA, in which case what you're seeing is normal. If the sticker says it's CA emissions, someone has swapped in an EPA computer to go with that engine.

 

Awesome thank you for the response!

 

Would be a good idea to put a code reader on and see what the codes are besides the O2 sensor.

Post up a pic of the front end so we can see what looks off.

 

I have a couple more but their just engine parts. i dont have a picture of the whole front of the jeep. its sitting in a garage 40 min away from me atm (where most of my tools are). Had a code reader on it befor i brought it home, all i remember is cylinder misfire, in number 6

 

I'm not an expert but the first thing I'd do is re-connect that vacuum pipe which is running from the front elbow on the top of your valve cover to the pipe on the side of the airbox. It won't make a huge difference but it would nag me when I was trying to troubleshoot.

Have you tested no6 spark plug to see if it is actually sparking?

That looks like a pre-97 engine to me, judging by the lack of a big flat airbox on top of the motor. Unless someone just couldn't be bothered to fit it of course!

 

Not sure if it is a pre-97, but definitely a pre-00, noting the lack of bolts on the coil-rail, at the very least it is likely a 0630/7120 head that was swapped on to replace a cracked 0331, possibly a complete pre-00 engine was swapped in.


It is possible that the coil rail isn't making good contact due to the lack of bolts (and possibly bad contacts/boot on the #6 plug) or it could just be a bad coil rail/wiring. I would recommend either making up some mounting brackets for the coil rail (you can use other bolts to attach to such as the valve cover and fab something up with sheet metal to hold the coil rail on) or ditch the coil-rail for a Dodge Viper Coil pack which you can remote mount.

 

Coil pack i have on it now is new but the viper coil pack sounds like a great idea, i'll look into it. thank you.
I had the hose connected at one point. it keeps falling off, its getting replaced.
After starting the vehicle and letting it run for a couple minutes I took the number 6 plug out and it looked like it did when i put it in, no evidence of firing what so ever.
Would the engine being a pre -97 effect anything?

 

Just an idea - try swapping it with a plug from a different cylinder.


I've had chainsaws go flat dead just from a bad plug.

 

It doesn't look pre 97, I've got one so it would ring a bell. You can see the manifold below the fuel rail is more rounded, pre 97 was squared off. Just looks like a dirty 2000 to me. Also check your plug wires as well and see if you are getting power at the wire.

 

Awesome, thanks for the reply's everyone!

 

That doesn't mean anything. Normally if you're going to swap an engine in a 2000 or 2001, you keep the newer intake manifold because it flows better. It bolts right onto the older head. There's also no reason to pay for another manifold when you have a better one already on the truck.

 

Just an observation; the fan shroud for mechanical fan is missing. It is an important part of having an effective cooling system.

 

That's fair, I should have added IMHO...I was looking at the manifold and also the pcm on the left side. The design changed on later models and looks very different. But I suppose it's still possible that it's a swapped motor, I just thought they would have needed to swap the pcm as well since the electrics are a little different as well.

 

Why would you need to swap the PCM? There are no electronics in the block or head. The PCM would be controlling the fuel and spark feeding the motor, and you'd be keeping the later hardware for all of that. If you're swapping in an older block and/or head but keeping the coil rail, it wouldn't run with the older PCM.

Where's Cruiser? This is about the time he usually shows up to set everyone straight.