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NEW JEEP NO RUN

dakotaNCA

NAXJA Forum User
I bought a 96 xj, 4.0 auto from a friend a few days ago. He bought it several months ago. The original owners said it had overheated, so they shut it down. They feared headgasket eventhough they did not drive it hot. So my buddy bought it for a song. They towed it home, it would not start. He and then I have checked the oil and water to find NO pollution to indicate a head gasket problem. My buddy thought the XJ had a fuel problem as it would not start unless fuel was poured into the throttle body. I could not get it to do even that.
I have

Replaced plugs
rotor
cap
wires
cam sensor ( i broke it )

I smell gas when cranking. I have pressure at schrader valve on fuel rail.

I have fire
i have checked rotor to piston at TDC ( timing )
I have checked primary and secondary resistance at coil ( Passed )

I think the motor cranks slow, and I did replace the battery. It sounds to me like an engine with broke timing belt, but sounds like it tries to fire on a couple of cylinders occasionally. This is my first 4.0 so I may be off on cranking speed.

By everything I know, and have read hear on FAQ. This thing should run. Please help me.:gee:
 
Ok.

Try this--hold the accelerator pedal to the floor, firmly, and crank it. That tells the PCM to cut fuel injection for a flood clear mode.

Fuel pressure at the rail, without knowing actual pressure, isn't much use. A little, but not much. Throw a pressure gauge on it an post up the number.

How is the spark? Snappy and blue?

The 4.0 has a timing chain, but if they stretch enough they will will jump timing.

Put a voltmeter between the battery terminals--should have about 12.5 volts if charged. Observe the voltmeter while cranking--what the voltage drop to while under load?
 
I tried that. I have 31psi.

Spark looks good. visual inspect shows lots of cracks in outer casing. but it ohms of to be in spec.

fuel pressure 31psi

scan tool says codes 320 340 no cam or crank reference signal at pcm. Cam and Crank sensors are new.

???????????????????????:firedevil
 
Ok, the synch sensor and crank sensor are new, so for short-form lets A**ume they are good.

You need to test the harness for open/shorts between each of the sensors and the PCM connector.
 
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