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Engine & Drivetrain "How-To" articles pertaining to the Engine and Drivetrain of an F150 (including Exhaust)

no spark mystery for someone better or more experienced than me

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Old 08-20-2016, 05:03 PM
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Default no spark mystery for someone better or more experienced than me

95' F-150 (of course), 5.0l, just dies one night on me and my boy. Check it out alittle, and no spark. Have power to the coil, but the primary isn't breaking to give me spark. The distributor is turning. Check the PIP wire at the ICM and it is pulsing. I figure the ICM is bad. Just happen to have one in a truck that was running but gonna scrap for other reasons. Swap the ICMs, still no spark. Odd because the other truck ran not too long ago. Just out of curioucity I take both possibly bad ICMs to my buddies house and put them each in his sister's truck. Truck fires right up on both ICMs. Obviously they are doing something right. I am kinda confused. I read an article that says you have to test the PIP with an LED or you can get a false test result. I start after the PIP which results in me installing a whole new distributor. Still no spark. Because a new part isn't necessarily a good part, I make myself an LED tester. I test my new distributor and the LED says the PIP is pulsing. In the process of all this, although a coil can't work unless the primary circuit is broken, I ohmed through and swapped out 2 good coils. So now here I sit with a truck that seems to have power everywhere it should. Components are doing their job properly, yet I have no spark. My next thought is I have a bad wire somewhere, and tracing it down won't be fun. Hope someone can help me with a different solution.
Old 08-21-2016, 04:26 PM
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Maybe the rotor has arc'd through? I've seen it happen before. In that case you'll have spark from the coil wire but not to the plugs.
Old 08-21-2016, 07:08 PM
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New cap and rotor on new distributor. There is no spark anywhere because the primary circuit isn't breaking. The cause of that is what I can't figure out. Thanks for the thought.
Old 08-22-2016, 09:00 AM
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Might be time to pull the computer and make sure it looks ok.
Old 12-08-2016, 09:43 AM
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Likely by now you fixed this, but under the hood is an additional fuse box.
The "fuses" are square modules. There are five of them. The center one regulates
if the fuel pump(s) have electricity going to them.



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