No spark

Tiny
MARK0105
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  • 1994 JEEP GRAND CHEROKEE
  • 4.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 225,000 MILES
Not receiving spark from coil. Fuel pressure is good. Replaced crank position sensor, distributor cap, rotor and cam position sensor. Replaced coil, spark plug wires. Still no spark. Battery is good. Neutral safety switch is good. Distributor rotor button Is spinning when being cranked over. Stumped. Any suggestions?
Monday, February 8th, 2016 AT 3:39 AM

10 Replies

Tiny
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Also forgot to add that I replaced computer.
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Monday, February 8th, 2016 AT 4:26 AM
Tiny
WRENCHTECH
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See if you have injector pulse using a noid light. If you don't, see if you have power at one side of the injectors when the key is firsr turned on.
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Monday, February 8th, 2016 AT 5:49 AM
Tiny
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I'll have to get my hands in a mood light to check. I am having fuel though. I replaced the pump 6mo ago. I hear it running when I turn the key. Also when I pulled a plug out it was damp. What will the noid test lead me to? Are you thinking ignition switch?
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Monday, February 8th, 2016 AT 4:47 PM
Tiny
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It will tell me if the power supply is going out and if the computer is receiving a reference signal. Noid lights are cheap, under $10. Just get the right one that plugs into your injector plug.

https://www.2carpros.com/images/external/1Noidlightpair__.jpg

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Monday, February 8th, 2016 AT 4:51 PM
Tiny
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Isn't the power supplied through the coil once the signal from the crankshaft sensor power and computer ground pulse? Which other power supply are you thinking?
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Monday, February 8th, 2016 AT 4:56 PM
Tiny
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Please just do the testing. I can't tell you anything without some information.
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Monday, February 8th, 2016 AT 4:59 PM
Tiny
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I will try it out tomorrow after work. I'll pick up the noid light tester on the way home and see what happens. I'm actually interested in what the results will be. I'll keep you posted. Thanks again.
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Monday, February 8th, 2016 AT 5:03 PM
Tiny
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While you're testing, use a test light to see if you have 12v going to both one side of the injector and the + side of the coil. This may only be there for a couple seconds when the key is first turned on.
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Monday, February 8th, 2016 AT 5:17 PM
Tiny
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Finally had an opportunity to check injectors. Checked three injectors using Noid light and it was blinking while cranking. I checked power at coil and had power. I bought another coil just to see if I was given a bad coil, no luck. Still not getting spark out of the coil. Getting frustrated. I heard somewhere the alarm could be an issue? I don't have a key fob so not real sure.
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Tuesday, February 16th, 2016 AT 3:59 PM
Tiny
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Are you saying that you didn't have 12v at the + side of the coil when the key is first turned on or when cranking?
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Tuesday, February 16th, 2016 AT 4:59 PM

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