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could a bad coil pack...


RumpRanger98

Well-Known Member
Joined
Feb 19, 2009
Messages
292
City
Tacoma, WA
Vehicle Year
1999
Transmission
Manual
I have read a post or 2 about someone having a coil pack that would spark on all 6 but was giving them problems because it was weak. Now im curious how you can test if the coil pack is giving weak spark?

I was also wondering if a bad coil pack could create an arching spark sound while driving through a certain rpm ranger under acceleration?
I cant visually check due to you have to be driving for this to happen. maybe I should place a video camera in the hood and drive around and see if it records any light or sparks.
 
You can check the resistance on the primary and secondary side of the coil packs for starters. Visual sparking at night is likely bad plug wires.
 
already check at night for sparks and misted water. no sparks. wires are new, plugs are new motorcraft.

I checked resistance where the plug wires connect and all of them were 0.8 ohms, in spec is 0.3-1.0 I believe. not sure if those are primary or secondary. where is the other spot to check resistance?

i only hear the "arched sparking" when accelerating in the 2600-3300 rpm range. and i am getting a cel for misfire cyl 1. im thinking my coil pack tests ok but has a small leak and only does it under load.
 
Last edited:
Across the corresponding spark plug connectors on each coil. Should be between 6500-11500 ohms.
 
first time ive ever owned a vehicle with a coil pack so im learning. what ones are the corresponding connectors? is it like cyl 1 and 4, cyl 2 and 5 and cyl 3 and 6? how does this motor fire anyway?

thanks for the help
 
FD-480T_FULL.jpg


Across the terminals of each pair of connectors.
 
first time ive ever owned a vehicle with a coil pack so im learning. what ones are the corresponding connectors? is it like cyl 1 and 4, cyl 2 and 5 and cyl 3 and 6? how does this motor fire anyway?

thanks for the help

It fires in pairs. If you look at the firing order you will notice that the packs are laid out so that when one is firing on the compression stroke its partner is firing on the exhaust stroke. If you try to run an old style timing light on plug one as we used to to set the timing you would actually see a flash at #degrees TDC (the engine spec) and one 180 degrees out. Or had a one of the old inductive pickup tester that would give you rpm reading you would read 2x the RPMs. Each plug is lit on the comprsion and exhaust stroke. It burns off an excess fuel in the exhaust (supposidly). :dunno:
 

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