My 97 F150 4x4 4.6 lit up the cel yesterday. I scanned it and got a no3 cylinder misfire.

My Chiltons gave a poor description of how to test the coil pack. However, from the center of the three terminals to the one on either side, I get 2.3 ohms +/- .1 ohm. The book seems to say .2 ohms, but I am not sure the book is right, and the other cylinders are ok.

Can anyone tell me what the primary and secondary coil resistance values should be.

Thanks.

My current plan is to replace the wire, then the coil pack and plug.

 

rkd-

I have a Haynes manual for the Mustang GT which I am assuming would be the same coil packs and it gives these numbers:

primary resistance in the coil pack should be .3 to 1.0 ohms.

secondary resistance should be 6.5 to 11.5 K-ohms.


It looks like you need a new coil pack. Hope this helps!

 

Thanks, thats the same value I had. Looking into a coil pack.

 

get some accels off summit. they will wake ur engine up a bit. they got rid of any detonation i was having.

 

You have a second coil pack that is not giving you problems. Use it for comparison valuse and testing.

Restisance readings of coils are seldom a reliable indicator of a coil's servicability unless the readings are way off.

Plugs and wires are far more likely to be the fault than is the coil.

Steve

 

I did ask the question because the values I got on the pass side coil pack were much higher than the Chiltons values. But both pairs were the same, so I figured that the book might be a bit off.

I still think mine are ok. I have been too lazy to test the other side, maybe this weekend. I wanted it fixed to put the boat back on the hill Wednesday after the Fourth.

I replaced the no 3 spark plug wire with a Motorcraft from the local Ford place, who sell them one at a time, and it seems to be fixed.

No more skipping and bucking, and the light has stayed off.

Thanks for the input. I will update if it fails again or really is the coil pack.

Probably going with a set of Taylor Spiro Pro wires on it soon.