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Old 12-20-2013, 06:14 PM
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My 94 ZJ

Hi guys I have a 1994 grand cherokee ZJ with a 5.2l v8 I have no spark and went threw everything literally I changed the crank sensor computer ignition coil pick up coil cap rotor plugs wires does anyone have any other ideas of why it might have weak spark
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Old 12-21-2013, 04:33 PM
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Quote:
Originally Posted by sincearZJ View Post
Hi guys I have a 1994 grand cherokee ZJ with a 5.2l v8 I have no spark and went threw everything literally I changed the crank sensor computer ignition coil pick up coil cap rotor plugs wires does anyone have any other ideas of why it might have weak spark
Might check for corrosion on the ground cables. Not just at the battery, check at the starter and where your ground wire meets the body, too. These old beasts crave clean power!
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Old 01-01-2014, 10:51 PM
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Re: My 94 ZJ

I have seen PCMs kill power to the coil... Verify with a testlight that you have power and PCM commanded ground. Put the testlight lead to ground and ensure one of the pins is hot with the key on. Im not 100% sure but I believe this power is from the ASD relay which will shut off after a couple seconds with no rpm signal so have someone turn the key over while your watching it. if it lights up your golden. Now put the test light lead on the B+ terminal and put it on the other pin... have your assistant crank the jeep over. if it doesn't flash you either have a wiring issue or you need a PCM.

Again, I have replaced numerous PCM's for this concern.

Another quick test you could do (not at all scientific or suggested as a "repair") but grab the PCM connectors and work them up and down (not disconnecting them, though you could do that too). Then try to start it. IF it starts, verify all the pins are clean, and then get a new PCM.
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