'96 4.0 cranks but won't fire/start
07-24-2009, 08:15 PM
#1
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Year: 1997
Model: Cherokee
Engine: 4.0
'96 4.0 cranks but won't fire/start
Last night my Daughter drove the Cherokee Country home and all was well. Today she gets in and it just turns over but nothing. I can hear the fuel pump so I start checking other things. It doesn't seem to have a lick of spark.
Since it ran perfect one minute and dead the next day, I doubt it's the plugs, wire, distributor. Any ideas on what might cause a completely sparkless situation?
Since it ran perfect one minute and dead the next day, I doubt it's the plugs, wire, distributor. Any ideas on what might cause a completely sparkless situation?
07-24-2009, 08:49 PM
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Model: Cherokee
ignition coil or ground wire
i had the same problem, my jeep was just working and it just died and wouldnt start. i have a 96 4.0 as well. i took it to a shop and they diagnosed it to be an ignition coil but it actually was a disconnected ground wire. hope this helps!
07-24-2009, 08:58 PM
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Year: 1991
Model: Cherokee
Engine: 4.0
Check the ignition coil... disconnect the coil secondary wire from the distributor and place it near (within 1/8") of the engine block, disconnect the primary connector from the coil and connect 12 volts to the pins on the coil for a second or two...when breaking the 12 volt connection you should see a nice fat spark from the coil secondary wire to the engine block (assuming the secondary wire is good). Lack of spark indicates a faulty coil.
07-25-2009, 09:46 AM
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Year: 1997
Model: Cherokee
Engine: 4.0
How in San Hell do they expect you to get to the bolt/nut that holds the ignition coil on? Using a nut is crazy! Luckily this Jeep has been so good that I haven't had to do any major maintenance thus far because accessing some of the components is crazy. Lord forbid the alternator go...
07-25-2009, 12:23 PM
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Year: 1997
Model: Cherokee
Engine: 4.0
Went and wasted money on a new coil and nothing. It doesn't appear to be getting voltage to the coil. Any ideas on that?
07-25-2009, 01:09 PM
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Year: 1991
Model: Cherokee
Engine: 4.0
Did you test the coil before you changed it out? Anyways, the ignition coil gets its 12 volt primary voltage on the dark green/orange wire via the automatic shutdown relay. The relay should be energized anytime the engine is cranking or running. Crank the engine for a full 5 seconds. You should have 10 -12 volts at the dark green/orange wire at the coil for the full 5 seconds.
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07-25-2009, 01:19 PM
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Year: 1997
Model: Cherokee
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Did you test the coil before you changed it out? Anyways, the ignition coil gets its 12 volt primary voltage on the dark green/orange wire via the automatic shutdown relay. The relay should be energized anytime the engine is cranking or running. Crank the engine for a full 5 seconds. You should have 10 -12 volts at the dark green/orange wire at the coil for the full 5 seconds.
07-25-2009, 01:31 PM
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Year: 1997
Model: Cherokee
Engine: 4.0
O.K. I did the check with the green/orange wire and when we first crank, it shows about 11.0 volts but almost immediately drops to almost nothing.
07-25-2009, 02:27 PM
#10
Caracticus Potts The Mod
sounds like a bad ground, but Also may sound silly but look at the o2 sensor wires under the intake manifold these wires sometimes lay up on the header pipe and short direct to ground which kills the engine because the crank and cam sensors share the same circuit.
07-25-2009, 03:33 PM
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Year: 1991
Model: Cherokee
Engine: 4.0
OK...according to the service manual, if voltage originally appears while cranking but then drops to zero after 1 or 2 seconds, the crankshaft position sensor circuit needs investigation. If the computer does not receive a crank position sensor signal within 3 seconds of cranking, it will shut things down. Looks like you may have a faulty crank position sensor or associated wiring.
07-26-2009, 02:05 PM
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Year: 1997
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RESOLVE!
I figured I would follow up as many times you find these threads but never read about the ending. It turned out to be the crank position sensor. After using my meter and checking resistance, it was a pretty good bet. This seems to be the main (internet searching) reason why these vehicles will crank but not fire. Oreillys took back the needless coil on top of it so I didn't waste money on needless parts. I did run to Sears and get a 10" extension and universal. All in all it was about a $90 job. Not bad considering that the garage would have raped me for several hundred.
Now the "other" part. If you ever have to change this part - be warned. If you are not one to cuss - you will start. If you are not one to get angry - you will. My arms are welted, cut, bruised & chaffed, but it was damn well worth it!
Thanks for the replies.
Now the "other" part. If you ever have to change this part - be warned. If you are not one to cuss - you will start. If you are not one to get angry - you will. My arms are welted, cut, bruised & chaffed, but it was damn well worth it!
Thanks for the replies.
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