Hey guys, so just a few days ago I finished a head swap on my 2000. Thanks 0331. Anyways, after finishing the project, got everything hooked up we let it run for about 30 minutes no problems at all, just the general smoke from all the oil and stuff. I turned it off and let it sit for a while. Later that day I drove it to get gas and the CEL came on, went and got it checked. My Camshaft sensor was throwing a code, so I cleaned it up and the light went away. Well now its gotten worse, it has a very noticeable rough idle, it sputters at acceleration, and the muffler is louder than ever. It all goes away at about 1500rpm. The rough idle will come and go as the Jeep gets warmer. Yesterday I cleaned every single plug and wire I could touch, it didn't go away. I gave the tb a real quick cleaning and the idle was a little less rough.
Are there any ideas out there? Its my DD and I need it to run like a champ.

 

Bad valve spring(s).

Remote possibility of collapsing lifter(s).

Fuel injectors not firing evenly.

 

Would that happen on a brand new head?

 

Bad valve spring(s)? Possibly. Did it come fully assembled?

 

Which Cam DTC was shown? P1391 or P0340?

Occasionally the wiring to/from the PCM/Cam Sensor will get chafed causing intermermittant to full time problems.

Inspect the wire looms at the back of the head for chafing through to the wiring within, and chafing of that wiring.

With the engine running, wiggle the wiring harnesses at the firewall, at the cam sensor, and near the PCM, and see if it causes any change.

 

What is the deal with "cleaning" sensors and other crap? These aren't Ford Model T's.

 

The head came full, from odessa cylinder. By cleaning I went through and unplugged all the wires, wiped them out, and replugged them back. To be completely honest I can't remember what p it was, the guy just read it off and went inside because it was freezing cold. I checked the looms out, they all still look good. Plastic coating on all of the wires.

 

I asked my brother and he remembered it was p0340

 

Did you try wiggling wire harnesses with the engne running to see if it made any change?

P0340-NO CAM SIGNAL AT PCM

Set Condition: At least 5 seconds have elapsed with crankshaft position sensor signals
present but no camshaft position sensor signal.

Possible Causes
POSSIBLE CAUSES
CHECKING INTERMITTENT CKP SIGNAL WITH LAB SCOPE
CHECKING INTERMITTENT CMP SIGNAL WITH LAB SCOPE
CHECKING INTERMITTENT WIRING WITH LAB SCOPE
INTERMITTENT CONDITION
5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND
5 VOLT SUPPLY CIRCUIT OPEN
5 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
CMP SENSOR SIGNAL CIRCUIT SHORTED GROUND
CMP SENSOR SIGNAL CIRCUIT OPEN
CMP SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
CMP SENSOR SIGNAL SHORTED TO 8 VOLT SUPPLY CIRCUIT
SENSOR GROUND CIRCUIT OPEN
PCM - 5 VOLT SUPPLY
PCM - CMP SENSOR SIGNAL
CAMSHAFT POSITION SENSOR

The diagnostics procedures calls for using a lab scope nd the DRBIII tool to analyze the problem. It does get into check the 5 volt supply to the cam sensor and reading resistance of the circuit wires.

It finally gets into checking the oil pump drive gear for wear, whch has been known to cause cam sensor problem.

If you have a factory service manual for your XJ it would help a great deal. Without it you are just guessing which will lead to many questions here in this thread and may end up you not getting the answers you need.

 

I tried the wire wiggle thing. It made no difference, when I did it. Tonight on my way home from work, the rear tires at about 45 to 50 mph started to jerk and lunge. I'm parking it until this problem is resolved.

 

Sloppy timing chain?

 

The Jerking and Lunging (bucking) sounds like mine every time another Auto Zone CPS craps out. Just cause the head is new (ish) doesn't mean the rest of it is..
Meter it out or replace it...
Just from my experience..

 

I understand that just because a new head is in doesn't mean everything is new. I just love how it was timed to happen this way. Whats the best way to test for said sloppy chain

 

Pull the timing cover and check the slack against allowable values.

In my experience, it's probably OK until and unless it jumps time. You'll know it when it does.

 

Pull cover. This is what my engine was doing with a failed lifter. Ran well just clacked like crazy. Did a top end rebuild with new cam, lifters, head checked, resurfaced and timing chain.