4.0 Coil Pack Question

[rangerich]

Can a single tower on a coil pack get weak, or does it only happen in pairs?

 

[shane96ranger]

The coil pack only has 3 coils in it. We can probably help better if we know what you're chasing down.

 

[adsm08]

A single tower can get weak.

Coil pack diagnosis actually depends on it. If you are chasing a misfire and have access to live data on the misfire profile, swap the suspect cylinder's wire with it's opposite on the pack. If the misfire moves the coil is your problem.

 

[rangerich]

Number 5 cylinder keeps throwing a miss fire also a rich condition on bank 2, Ive replaced plugs with Motorcraft and wires.

 

[adsm08]

Well a misfire, or a number of misfires would actually cause it to show a lean condition. It judges rich/lean by oxygen content in the exhaust, so not enough fuel in the mix dumps lots of oxygen and throw it lean, but no fire in the mix dumps a lot of oxygen in the exhaust and makes it read lean.

Rich means is doesn't see enough oxygen in the exhaust so it wants to reduce fuel.

 

[94Reborn]

If it isn't the coil, the next place I would check is the injector.

 

[Maritime Storm]

I was thinking injector not coil, a misfire is detected by the computer as a lean condition not rich. The O2 sensors sense oxygen only, when a cylinder misfires the air/fuel mixture goes down the pipe but the sensor only "sees" the air.