2002 TJ starts then dies

[mudreadytj]

im new here just found this site. Ive got a major problem and so far no one can help or give a sensible explanation for the cause. here is what ive got:

2002 TJ 4.0 it will crank and start as soon as it build oil pressure it dies. I put a code reader on it and get a code 1686 manf. control. Ive done research and a code 1686 is (no signal from SKIM module), ok problem solved right its the chip in the key. WRONG it doesnt have the coded key and never has the reason I know this is I bought the Jeep brand new with 17 miles on it in 2002. Ive replaced the fuel pump, camshaft position sensor,ignition switch, coil packs, map sensor, mass airflow sensor, that just leaves the crank sensor and the computer to replace. Ive asked on several forums and havent gotten anything close to a sensable answer. The only answer Ive got was from a tech at a dealership and he said " The PCM (powertrain control module) picked up a signal from somewhere. Maybe somebodies key fob in the parking lot at walmart. Its tricked itself into thinking it has a S.K.I.M. key, and now it wants that signal every time to start the vehicle. " thats all fine and dandy but how can the PCM pick up a signal when it doesnt have a reciever and that doesnt explain that my Jeep hasnt been to a walmart parking lot in over 2 years. The only vehicle it has been around with keyless entry is my truck. and ive tried cranking my jeep while pressing the button on my trucks remote and nothing.

So any help yall can give me is much appreciated. BTW I know some of yall will ask and yes it ran fine for a couple weeks after i changed the ignition switch and the reason i changed the switch is I was getting no power to the HVAC controls or B/U lamps. Also I know for a fact that the converters arent clogged.

Sorry for the long post just trying to describe my problem and give as much detail as possible.

Thanks

	Crank position sensor A crank sensor is a component used in an internal combustion engine to monitor the position or rotational speed of the crankshaft. This information is used by engine management systems to control ignition system timing and other engine parameters. Before electronic crank sensors were available, the distributor would have to be manually adjusted to a timing mark on the engine.

[SteelHeadz]

Just for clarification, the key is Black or gray?. It is impossible for a non S.K.I.M. vehicle to initialize a module that's not there. It's manually set in the vehicle configuration build from the factory or thru the use of a DRB3.

[JeepRox]

I would check the Crank Sensor..I had issues with this before too..once it heats up it will cut out then when cooled start again...

	Crank position sensor A crank sensor is a component used in an internal combustion engine to monitor the position or rotational speed of the crankshaft. This information is used by engine management systems to control ignition system timing and other engine parameters. Before electronic crank sensors were available, the distributor would have to be manually adjusted to a timing mark on the engine.

[mudreadytj]

Originally Posted by SteelHeadz

Just for clarification, the key is Black or gray?. It is impossible for a non S.K.I.M. vehicle to initialize a module that's not there. It's manually set in the vehicle configuration build from the factory or thru the use of a DRB3.

It is the Black key. Ive driven it for 2 years with a key I had made at walmart so I know it doesnt have the SKIM . thats what Ive thought to.