00 expidition. crank no start.has 40 psi fuel pressure, has spark, has 120 compression on both banks has a good crank signal.i dont know what else to check.

check the compresion in all cylinders 100 psi (compression good) check the spark -check the fuel pressure.30 psi at gauge with switch on.(if no keep pressure with switch off injectors or fuel pressure regulator are bad
check the signal to the injectors (get little injectors tester at autoparts) if no signal check the ground to the injectors black wire
or the other wire (computer)= good signal to injectors and good fuel pressure and good spark (defective injectors)

Misfires are caused by one of 3 things-gas, spark, or compression-one of those is the problem. For gas, check the fuel pressure and see if it is at the right pressure for your car. Low fuel pressure will cause misfires. If pressure is good, it could still be an injector problem, like a clogged injector. If low pressure, suspect the fuel pump or the fuel filter.
For an ignition spark problem, check your spark plugs. Pull them out and inspect them for broken or cracked plugs, check the spark plug gap, check for oil fouled plugs. You may be able to isolate the misfire to a cylinder or two by the plugs condition. A misfiring plug or cylinder should show more black, sooty deposits than the other plugs. A normal firing plug will have a tan or brown colored insulator on the end with very little deposits. If the plugs are okay, clean them a bit if needed, and check for spark on the spark plug wire ends with engine cranking. Buy an inexpensive spark tester, or hold each spark plug wire metal end terminal 1/4 inch from a ground on the engine block, while cranking the engine. Wear a heavy glove to avoid getting shocked. Check that every cylinder is getting a strong blue spark to eliminate ignition as a problem. A weak, yellow or orange spark is an ignition problem, possibly a bad coil, or other ignition part.

If spark and gas is good, you may need to check engine compression. Any cylinder that has significantly lower compression than the other cylinders will cause a misfire, and set a misfire code. You should check for any trouble codes in the engine computer. A code reader or scanner would have to be connected to the diagnostic connector under the dash. What is "significantly lower" compression? About 15-20% less compression. Say you checked and had 150 psi compression in most cylinders. If one had 20% lower compression ( 150 X 20%= 30 psi, 150 -30 =120 psi, or same as saying 150 X 80%= 120 psi.), a condition like that can cause a misfire. I hope I have made sense here. Good luck, and post back what you find, or if any questions.

If you have spark at all the plugs, the crank sensor should be ok. You should use a gage to check fuel pressure? I don't know engine size? For the 3.1L engine, my info says 40--46 psi.
It is possible to have spark at the plugs, but, the computer doesn't see rpm signal. If that is the case, no fuel injector pulse. The purple wire with white tracer carries rpm signal from ignition module to pcm, that wire has dc pulse, engine cranking. If nothing there, have to check ignition module.
How long since a tune-up? Any applicable trouble codes?

did you fix this yet, old post.
which engine, we cant guess that. ever.? (we know it's not a diesel)
if the engine has spark and fuel
and it dont start:
it's flooding? (spark tips soaked in raw fuel, ) we look at them......
did you try the operators guide trick, cranking with wide open throttle?
this cuts fueling , clearing a flood condition.
spec, is 120 to 150 PSI. 4.0L
or 4.7L?
good spark to ALL cylinders is the correct test, not just 1.
does the timing light show correct timing? cranking? spark timing?
ever do a tuneup, with new spark plugs yet.
If the above is true it will start. or at least on test fuel.

one way to find problems like this , if the spark is good.
is to cut all fuel injections. (i kill the fuel pump, ask how.)
and start car with test fuel, if it runs for 3 seconds each try.
then all is good , engine and spark, if not , not.
a simple test. that is. and works on all gas engines.

watch scotty.
http://www.youtube.com/watch?v=064Ilsz8Fzg&NR=1&feature=fvwp

in this case he assumes the engine is good. and timed right.

FSM
http://www.jeep4x4center.com/knowledge-base/index.htm?utm_source=cj#service

I can run any engine, with no fuel in car. sure can.
and is safe to do.
use CRC.
http://www.crcindustries.com/ei/product_detail.aspx?id=05671

Remove a spark plug and see if its wet with gasoline....it could be flooded.

Compression is too low, it sounds like there is a head gasket failure. The compression should be above 100 psi as a minimum. Normally should be in the 120-170psi range.

Hi!

The O2 sensor should be on the Exhaust manifold or pipe.

Raise the vehicle and support it with jack stands and try to disconnect the electrical connector. Then unscrew the sensor from the Exhaust Manifold and you might need the O2 socket to do so as its available at any autopart store, Be careful no to damage the threads, then Try to put in the New O2 sensor and be careful with the head of the sensor not to damage it and the installation is the reverse of the removal. and connect the electrical connector back and start your car.

I still don't understand How an O2 effect your car starting because it has no relation with starting. But any how hope this helps and if you got any other questions Bro , Feel free. Good luck

Well you need fuel to the injectors, a spark, compression, air and a signal to the injectors to fire for the engine to start.
So if you've got fuel, make sure you have spark to the plugs, the air filter is not clogged, compression is above 120, and the crank and cam positions sensors are good.

Engine Cranks But Will Not Start

For an engine to run, you need three things to happen inside the engine. Compression, fuel and ignition, without any one of these components the engine will not run.
Basic Checks:

A. Test Fuses. Test both under hood power distribution center and the fuse panel under dash. This is done with a test light tool. The test light should illuminate on both sides of the fuse, if not the fuse has failed and needs to be replaced.
B. Testing Fuel Pressure Test for proper fuel pressure with a test gauge on the fuel rail, most throttle body injection cars (TBI) are between 13 psi and 17 psi. and most (DPI) direct port inject systems are between 40 psi and 55 psi. If no or little fuel pressure is observed and there is 12 volt power present the fuel pump, the fuel pump needs replacing.
C. Checking Timing Belt Test for compression by removing a spark plug and insert a compression gauge. Crank the engine over about 5 seconds the gauge should read between 125 psi and 165 psi, if no compression is observed remove front engine cover to inspect timing belt or chain. Crank engine to observe cam rotation, if the cam does not rotate the timing belt or chain has failed. (note: if the timing belt drives the water pump it is best to replace the water pump at this time)
D. Test for Injector Pulse Remove injector connector to insert injector test light (node) or volt meter. Observe light flash or gauge pulse while cranking. If light/voltmeter doesn't respond, an ignition distributor/crank angle sensor (CKS) or an ignition module is most likely your problem.
E. Test for Ignition Spark Remove spark plug wire, insert an extra spark plug into end of wire, rest spark plug next to a ground source then crank engine. You should observe a blue spark between the spark plug gap and ground source. If no spark is observed, an ignition coil, ignition rotor or spark plug wires might have failed. (always keep hands away from engine when cranking)

1. Test Fuses. Test both under hood power distribution center and the fuse panel under dash. This is done with a test light tool. The test light should illuminate on both sides of the fuse, if not the fuse has failed and needs to be replaced.
2.Testing Fuel Pressure Test for proper fuel pressure with a test gauge on the fuel rail, most throttle body injection cars (TBI) are between 13 psi and 17 psi. and most (DPI) direct port inject systems are between 40 psi and 55 psi. If no or little fuel pressure is observed and there is 12 volt power present the fuel pump, the fuel pump needs replacing.
3.Checking Timing Belt Test for compression by removing a spark plug and insert a compression gauge. Crank the engine over about 5 seconds the gauge should read between 125 psi and 165 psi, if no compression is observed remove front engine cover to inspect timing belt or chain. Crank engine to observe cam rotation, if the cam does not rotate the timing belt or chain has failed. (note: if the timing belt drives the water pump it is best to replace the water pump at this time)
4.Test for Injector Pulse Remove injector connector to insert injector test light (node) or volt meter. Observe light flash or gauge pulse while cranking. If light/voltmeter doesn't respond, an ignition distributor/crank angle sensor (CKS) or an ignition module is most likely your problem.
5.Test for Ignition Spark Remove spark plug wire, insert an extra spark plug into end of wire, rest spark plug next to a ground source then crank engine. You should observe a blue spark between the spark plug gap and ground source. If no spark is observed, an ignition coil, ignition rotor or spark plug wires might have failed. (always keep hands away from engine when cranking)