Stewhatch

Driving my Jeep recently has been like running thru quicksand. CEL has come on and I checked the codes this evening. Got six (!!) numbers - P 0320 (Crank ref signal), P 0300 (random multiple cyl. misfire), P 0302 (cyl. #2 misfire), P 0305 (cyl. #5 misfire), P 0306 (take a guess), and finally P 1494 (Leak detection Pump sw or mechanical fault). What the heck is a LDP or leak detection Pump? Car starts fine and drives, it's just super sluggish and the slightest incline kicks the tranny up a gear. I just replaced the Crank reference sender w/ a new unit in July so I doubt that is an issue since the car starts and runs (I have ignition). Is there an easy diagnosis given what codes I have showing or am I destined to leave my Jeep with a tech for a few days to get things right? Car has 169K on her. Maybe time for a major tune up or is this much more then that? Cheers ...

maverickdan

possible causes for p0320
Tone wheel/flex plate damaged
5 volt supply ckt open
Irregular lab scope pattern of ckp signal
Stray signal from the camshaft position sensor
Wiring harness intermittent defect
Sensor ground circuit open
CKP signal ckt open
CKP signal ckt shorted to ground
5 volt supply ckt shorted to ckp signal ckt
CKP signal ckt shorted to sensor gnd ckt
PCM defective
PCM defective
CKP sensor defective
CKP signal ckt shorted to voltage

the misfire codes could be as simple as bad gas or just needing a tune up
the pump thing might have some bad vacuum lines going to it

Stewhatch

CKP = ??? Thanks for the reply - I wonder how bad this really is.

maverickdan

ckp= crank position sensor

Stewhatch

I am hoping that all I need is the major tuneup. How often do the coil packs need changing? On another subject, has anyone done a 4.0 to 4.7 conversion? I have a chance to buy a matched 2004 4.7 motor and transmission: would they bolt in to my Jeep without too much effort? The 4.7 comes with all the electronics / wiring harness, etc.

maverickdan

coil packs should not need changing, the 4.7 swap should bolt in with new mounts, you will need a pcm and harness to go with it but not 100% sure, and in my opinion the 4.0 is a far better engine

Stewhatch

i agree on the 4.0. My other Jeep is a 2004 Ltd w/ the 4.7 and it has so much more oomph with the same gas mileage. I was considering the swap as a cheaper alternative, but the 4.0 has been trouble free till now, with minimal maintenance. Doesn't leak a drop of oil. Thanks for the help.