At this point, I would pull my fuel rail, hand it to a buddy, crank and see if you are getting fuel . I know you have pressure, are these injectors OEM?

Stupid question, did you ground the engine? You mentioned the great looking spark .... Just thinking out loud.

I have tested the cam sensor input and output voltage, and output jumps from 0 to 5 like it is supposed to. I don't have an oscilloscope to make sure the waves are square, but my quick and dirty test looked good.

The engine is grounded. I ohmed out all the grounds and even added a few with jumper cables to make sure everything is happy.

I'll pull the fuel rail and test it carefully. Thing is, I can't get it to run on starting fluid. It should run on starting fluid whether or not the injectors are working.

I'm about ready to have a shop hook up a real computer to it to see what they can see. Sometimes you have to bite the bullet and admit defeat. I've never been stumped like this before.

I think you have us all stumped. Did you ever get the timing light to trigger on the plugs? Just seems like if it wont run on starting fluid then the spark is occuring at the wrong time??? Maybe you can pick up the induced voltage on the coil packs when they are pulled and grounded. Should have thought of that when I suggested pulling the coils before.

You said your building proper compression and there is no back pressure out the intake so it seems like, correct me if I am wrong, the timing chain is installed correctly.

im not sure if it would fire with gas pedal to floor and spraying starter fluid that could be resulting in flooding

http://www.jeep4x4center.com/jeep-se...toolbar=0 read page 8d-17 about scan tool usage

I couldn't get the timing light to pick up anything. I'm not sure why. The timing light pickup won't fit around the plug boot, but I had it on the inline spark tester and still nothing.

Holding the pedal to the floor should put the engine into "flood mode" which stops the injectors from firing completely. At least that's what I've been told. If I'm wrong, then yes, it's probably flooding.

The scan tool that they hook up to sync the cam sensor is only used after the engine is running, and supposedly doesn't affect spark timing directly. The toothpick method is supposed to get it close enough to run, and a lot of people even say you don't need to ever hook up a DRB. I'll worry about that if I ever get it running.

yeah I read In my 98 manual to hold pedal down if its flooded. my battery died randomly and I cranked so much that it flooded. itryed jumping it and it tryed to start, then I read in the manual and did that and it started...

No love from the inline spark tester either? Our jeeps take resistive types plugs, but I don't know if this would cause the inline tester not to work. It takes much less energy to gap a spark plug in free air compared to compressed in your cylinders, I wonder if you have weak spark for some reason? Coil pack going bad? Do you have a donor to swap in lying around? What kind of plugs are you using? Your PCM has a good ground right? The PCM grounds the individual coils to make the spark so if it has a bad ground, might lead to bad spark.

Your jeep has me perplexed, and I am just hoping you next post will be "got it"

just by some chance do you have a few plug wires crossed?

I'm not lucky enough to have plug wires to cross. No distributor or plug wires on 2000+.

I've tested all grounds and they are fine. My inline spark tester shows spark, but I was trying to hook up the timing light to the tester and that didn't work. I grabbed another spark tester with adjustable gap and I had spark jumping over a 1/4" gap, so that's pretty good. I also hooked up a remote starter and bumped the engine over and watched the spark and harmonic balancer, and I seemed to get spark a few degrees before TDC, so my spark seems to be in the right neighborhood.

I have decent compression and all, but I'm wondering if something isn't happy in the engine itself. This just doesn't make any sense.

one sec i work at a chrysler dealer so i should have read it was a 2000 lol let me get on the chrysler dealer site real quick stay on here i need the last 8 of the vin

YL273341

has spark and fuel pressure? and you checked compression right?

im still lookin but here is a lil see if it helps at all ill keep looking


On 4.0L 6-cylinder engines there are three sets of notches Sensor Operation - 4.0L 6-Cyl. Engine
The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM. For each engine revolution there are two groups of four pulses generated on 2.5L 4-cylinder engines. There are 3 groups of four pulses generated on 4.0L 6-cylinder engines.
The trailing edge of the fourth notch, which causes the pulse, is four degrees before top dead center (TDC) of the corresponding piston.
The engine will not operate if the PCM does not receive a CKP sensor input

Battery voltage is supplied to the three ignition coils from the ASD relay. The Powertrain Control Module (PCM) opens and closes the ignition coil ground circuit for ignition coil operation.