Finally got to see my XJ in person from coming home from deployment and few kinks I have to workout before doing any mods. Wanting it running right because it's also my daily driver.

1.) The no bus issue on the cluster. My father took out the cluster and cleaned the connections before doing the roadtrip from Chicago to Camp lejeune, NC and it worked fine until now. Time to replace the connections.

2.) Squeling when I turn on the ac. Hopefully just a pully and not the compressor.

3.) Last but not least the big problem. Runs great but really rough idle. Bad gas milage and smell a bad smell. Like it's running really rich. ALso noticed when I started it black stuff came out the exhaust on to my new garage. (kind of OCD lol) Kind of sounds like a misfire at idle. Have done a full tune up and Air Raid cold air intake.

BTW it's a 2001 Jeep cherokee 4.0 4x4 automatic. Your suggestions are greatly appreciated and your help in the past has been a great help.

 

Semper fi! my ac compressor sqeaks when the ac is on. What I did was spray the front of the compressor with WD-40 and the sqeal went away lol!! No check engine light?

 

Mine was running very rich and idling rough. I figured it couldn't be vacuum cause that wouldn't make sense right? Well on my current teardown I was inspecting vacuum lines among other things and found the line to the map sensor was almost completely broken. The map sensor uses vacuum to help regulate a/f ratio. When you stand on the skinny pedal and the butterfly opens the vacuum drops and the map richens the mixture to compensate for the load. With no vacuum the map should have been essentially running in an " open loop" type situation. It would think it was always under load due to the lack of vacuum. Just a thought..... I haven't looked into the components on an 01 too much and am not familiar with the electronics so I may be way off base. Black stuff out of the exhaust is most likely carbon build up from your rich condition blowing out the exhaust. If this doesn't pan out let me know and I will familiarize my self with the engine systems in the 01 and take another crack at it lol

 

The MAP sensor on the 01 has a rubber boot that connects to the TB. Check the condition of the rubber boot. A good cleaning of all engine grounds is always a good idea. Check your battery cables for corrosion. Cleaning the IAC and TB is always a good idea. Also check the connection plugs to the IAC, TPS, and MAP sensor. Look at the wiring harness for open wires that may be grounding out. My 01 had open wires to one fuel injector that caused some problems with rough idle. Did you change out the coil pack when you did the tune up? Getting in close and inspecting all these sensors and cleaning the grounds won't cost anything but some time and you might find the problem. Oh yeah spark plug gap is correct right and did you use champion plugs?

 

Semper fi but even though I'm in a Marine unit. I'm actually a sailor. I did change the coil packs. Sounds like the connection to the map sensor might be the culprit of my problems. Then ill check out the O2 sensors and the timing. Checking all the grounds and and replacing the battery terminals conections is on my to do list in maintainence along with dif seal covers and possibly rear main seal. I've had four jeep cherokee's and all of them leaked in the rear main seal but this is the first time I'm trying to fix it. I usually just add more oil. Thanks again for the help.

 

Just pulled apart my throttle body cleaned it along with the iac and cleaned all the connections and reset the computer. Seems to be having the same issue. Not as bad but low idle and runs rough. Smells like its running rich too but no check engine lights. Any ideas?

 

Also the line to the map sensor seems to be fine

 

just because the lights not on dont mean theres not stored codes i would check them

 

Thank you for your service to our country.

 

Thanks leaving this country makes me realize how good we have it here.I will check out the codes see if there are any.

 

Alright checked for codes and it's a no go.no codes.completely lost, just know it idles low and rough and round rich.cleaned the iac and throttle body.could it be dirty injectors?

 

Any ideas would be greatly appreciated

 

See if you can get a fuel pressure gauge. Hook it up to the fuel rail then start the engine and check the operating fuel pressure. IIRC It should be about 50psi. If it is higher your fuel pressure regulator is likely malfunctioning. Shut the engine off and check the pressure. It should not drop below 30psi in 5 minutes. If it does you might have a leaking injector.


As for the squealing on the belt, the belt may just need to be adjusted tighter.

 

not even a end of test code ?

 

I'll take it to the shop and check the fuel pressure. As for the squel I put wd40 on the ac compressor pulley and it was good to go. But now it doesn't blow very cold air at all. Don't care as long as I can roll down my windows for now. And no codes at all. I had autozone check it.