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  #1  
Old January 22nd, 2013, 10:43
88magnum 88magnum is offline
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Crank, no start on a '96 XJ.

Hello, I am new here, so pardon my ignorance if a similar thread already exists.

Having trouble starting the Jeep. It began in the woods.

Was out wheeling and at one point it wouldn't start. I just kept trying it and eventually it did. Got home, replaced fuel filter (which was probably there since 1996) and it worked fine for several weeks. My buddy said it might need a new fuel pump as well.

Went back out to the woods, same problem. Wouldn't start. This time my friend started seriously suspecting the fuel pump. We purged the line, primed it a couple times without starting (he said the pump wasn't making enough pressure to open the injectors) and it started right up.

We got it home, and drove it around town the next day (Sunday), everything was working. Monday morning my girlfriend takes it to work, it starts up, then dies on her in the middle of the highway. Couldn't get it started with the purging/priming thing, towed it home.

Bought a new fuel pump, was about to put it in, realized I have a full tank of gas. So now I have a few questions:

1. Is it reasonable to assume that my mechanic friend is correct and it is indeed the fuel pump that's bad or is there something easier to try first? There's fuel in the line when I prime it, but it doesn't start. He says it's working enough to pump the fuel, but doesn't create enough pressure to open the injectors.

2. How the hell do I drain the fuel? I tried siphoning, but it seems I have a screen in there which prevents that. Is my only option to drop the tank now or ar there drain plugs under the plastic "skid plate" crap?

Thanks in advance for any suggestions.
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  #2  
Old January 22nd, 2013, 16:10
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Ecomike Ecomike is offline
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Re: Crank, no start on a '96 XJ.

Your mechanic friend is an idiot, if that is indeed what he said. The pump does not open the injectors, an electrical signal from the ECU computer does.

Back up and start over. #1 is there any spark at the spark plug? Pull one spark plug wire at the plug and stick a spare spark plug in it, then ground the body of the spark plug to the engine block, and have some one crank the engine. If no spark it is 99% of the time a bad CPS Crankshaft Position Sensor.

If you have spark, rent or buy a pressure gauge for testing fuel pressure at the local parts store. Then test the fuel pressure at the test port. Any real mechanic would know that!!!!

If the pressure is not close to 49 psi then the question is do you have power to the fuel pump, or enough power. There is a fuse, and a relay and IIRC a ballast resistor in the power feed to the fuel pump. TEST THEM next!!!!!!

If you have 12 volts at the fuel pump and low pressure, then look for a crushed fuel line next. Lastly if you need to drop and drain the fuel tank, DO NOT install an AIRTEX fuel pump!!!!! Get a Bosch fuel pump!!!!! Airtex is JUNK!!!!!

Also, if it is low pump pressure, it may just be a dirty suction filter in the tank or a loose hose on the pump outlet, and not the pump!!! Good luck!
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Old January 22nd, 2013, 16:13
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old_man old_man is offline
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Re: Crank, no start on a '96 XJ.

Like the man said, troubleshoot and see if you have spark. If no spark, percentages point to a TPS.
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Old January 22nd, 2013, 17:02
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birchlakeXJ birchlakeXJ is offline
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Re: Crank, no start on a '96 XJ.

Quote:
Originally Posted by Ecomike View Post
YBack up and start over. #1 is there any spark at the spark plug? Pull one spark plug wire at the plug and stick a spare spark plug in it, then ground the body of the spark plug to the engine block, and have some one crank the engine. If no spark it is 99% of the time a bad CPS Crankshaft Position Sensor.

If you have spark, rent or buy a pressure gauge for testing fuel pressure at the local parts store. Then test the fuel pressure at the test port. Any real mechanic would know that!!!!

If the pressure is not close to 49 psi then the question is do you have power to the fuel pump, or enough power. There is a fuse, and a relay and IIRC a ballast resistor in the power feed to the fuel pump. TEST THEM next!!!!!!

If you have 12 volts at the fuel pump and low pressure, then look for a crushed fuel line next. Lastly if you need to drop and drain the fuel tank, DO NOT install an AIRTEX fuel pump!!!!! Get a Bosch fuel pump!!!!! Airtex is JUNK!!!!!
^^^This.

Job #1 for a no-start is always to verify if you have spark. And to add something to the discussion on spark, it must be a QUALITY spark. You are looking for a strong, BLUE, snapping spark. Yellow/orange/white indicates a weak spark which may not be strong enough to start the engine

The ignition coil is usually responsible for weak spark, crankshaft position sensor is a primary suspect for NO spark.
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  #5  
Old January 22nd, 2013, 19:25
joe_peters joe_peters is offline
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Re: Crank, no start on a '96 XJ.

Gee, I don't know.

My Harry Potter magical mechanic's wand lets me diagnose the fuel system without using a fuel pressure gauge, so maybe his buddy has one of those too.

Fuel system must have the correct PRESSURE and deliver the correct VOLUME of fuel.

As my erstwhile friends already stated--determine what is MISSING and you are on your way to figuring out what is WRONG.

You may have a thermal failure in your CPS.
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Old January 23rd, 2013, 03:30
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xjtrailrider xjtrailrider is offline
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Re: Crank, no start on a '96 XJ.

I own two 96 XJ's. I have had this issue before.

1) verify fuel pressure WITH A FUEL PRESSURE GAUGE! They are cheap and can be rented at Oriellys etc. I think the spec is 39psi with the key on, someone will correct me if I'm wrong

2) Verify spark as explained above, with an old spark plug on a wire and grounded to the block.

Here is what I have had problems with in the past;

CPS= no spark

Fuel pump= no fuel pressure

I have replaced 3 ignition coils between the two 96XJ's, they over-heat and the casing cracks causing an "open" condition in the coil and no spark. The coil is in a bad spot and is a PITA to get to.

And lastly, the ASD relay(Automatic Shut Down). I have replaced one that failed on the trail.

I'm going with the coil but you need to be a mechanic and do some diagnosing, don't just throw parts at it!
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Old January 23rd, 2013, 21:54
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Runnin'OnEmpty Runnin'OnEmpty is offline
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Re: Crank, no start on a '96 XJ.

Quote:
Originally Posted by 88magnum View Post
......... Is my only option to drop the tank now or ar there drain plugs under the plastic "skid plate" crap?.....
If you do end up changing the fuel pump, you can
get to it without dropping the tank. The pump is
canted toward the front, so it can be removed by
raising the back of the Jeep enough to work underneath.
BE CAREFUL!!! Do not strike sparks when tapping the
retaining ring off. Use a brass or plastic hammer; do
not strike steel on steel.

However, I would definitely buy a fuel pressure gauge
and check the pressure before changing the pump.
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