Ignition coil question

[LBCRanger]

so my truck started to run like shit the other day and the CEL came one,i narrowed it down to the ignition system,im not getting any spark from the coil to cylinder #3.Would that mean the whole ignition coil is bad? or is it something else?

 

[sparky]

What year truck?

 

[TomB1269]

If it is the truck in the photo, then it is 99 or newer, and coil packs.
LBC, are you getting spark of the opposite post on the coil pack (each pack fires 2 cylinders at each cycle). If 3 is out and the coil pack is the problem then its partner should be out as well. If not check the wires and plugs (replace if it has been a while).

 

[LBCRanger]

If it is the truck in the photo, then it is 99 or newer, and coil packs.
LBC, are you getting spark of the opposite post on the coil pack (each pack fires 2 cylinders at each cycle). If 3 is out and the coil pack is the problem then its partner should be out as well. If not check the wires and plugs (replace if it has been a while).

thats the weird thing, the opposite side was firing perfectly fine. I tested each plug from the coil pack and the number 3 was the only one not firing.I have since changed the coil and it works completely fine.Is it normal for just one to go out like that? though it was kind of weird.

 

[LBCRanger]

Does anybody have a clue? this site has been letting me down lately..

 

[Ranger44]

That 6 pack is just like 6 little mini coils. So yeah, it's possible for just one to go bad.
Just as possible as the single coil on a TFI ignition system to go bad. It just wears out.

 

[Bob Ayers]

That 6 pack is just like 6 little mini coils. So yeah, it's possible for just one to go bad.
Just as possible as the single coil on a TFI ignition system to go bad. It just wears out.

No, there are actually 3 coils, firing 2 plugs each. If the coil (primary or secondary) develops a problem, it will kill the spark on 2 plugs. However, if the case of the coilpack develops a crack, or carbon track, it can short out one of the secondary terminals, in this case the one for plug #3. Plug #4, which fires in series with plug #3 will continue to fire.

 

[Ranger44]

ah, dude, I forgot about waste spark.

There are always 2 plugs firing at the same time. One on power stroke and the one that's on the exhaust (waste) spark. This basically tries to burn any of the unburnt HC/fumes before they leave the cylinder. So only 3 coils are needed.

Whoops.

 

[Bob Ayers]

ah, dude, I forgot about waste spark.

There are always 2 plugs firing at the same time. One on power stroke and the one that's on the exhaust (waste) spark. This basically tries to burn any of the unburnt HC/fumes before they leave the cylinder. So only 3 coils are needed.

Whoops.

Well, the plug fires at the top of the exhaust stroke so the cylinder is pretty much emptied.......

 

[Ranger44]

Well, the plug fires at the top of the exhaust stroke so the cylinder is pretty much emptied.......

It's done primarily for emissions.