I would think that you would check one the same way has a "single" coil. The ohm's may differ a little, but yes, the numbers should differ from a good one.

 

Yeah. All you need is a multimeter and a couple of pins to tap wires. You can read the resistance very easily. Ill post what the good and bad numbers are for testing tomarrow. Ive got them from when I first installed the stacker. I had some problems. Im crashing now though

 

In July Ford almost doubled the price of coil packs to us Dist.
I have them in stock for $43.00ea. I was selling them for less than $30.00 just last mo.
Remember the 01 tail lights?

Mark/LFP
www.lightningforceperformance.com

 

Mark,
Did you get my email.

 

I had one go bad. You will now if you have a bad coil pack. My truck ran very very rough. I changed all of them to stay on the safe side.

 

Y2K 7700 4x4

You need to a little "learnin" on the basics of what/why drives an automotive ignition system.

 

Hey Casper, i'm having that problem now where my truck is running more rough than usual.. Did you truck skip very bad at idle? I was wondering if a coil pack was gone semi bad is it possible the truck won't skip but lack a nice bit of Horsepower? I called JDM and they said if a coil pack went bad, I would definitely notice a bad skipping but i'm not seeing that.. When you replaced your coils did the truck run like new i.e. more horses?

 

When I changed the coil packs it made a differance. The truck never idled better. It made a big differance when I changed the plugs. The reason I changed them was because JDM had them for $25 each. I couldn't pass that up. The dealer was selling them for $50.They have gotten alot more expensive since. JDM told me that new coil packs are a better design than the 99's. I guess they have been revised atleast three times since 99. I would change the plugs to see if that helps. If not get one coil pack and switch it with the other so you can find the bad one.As far as horse power I really don't know. NoelVM a member on the boards gained one tenth from changing the coil packs.

 

you are correct sir... a coil pack is the same as any traditional coil used with a distributor, only a smaller version. it is very simply two pieces of wire both coiled up, one in a small coil and the other larger coil wraps around the smaller one.

by passing electricity through one coil, a larger voltage spark is "INDUCED" in the other coil. this is how your high voltage spark is created.

anyway back to the point, if you measure the coil with a Digital Volt - Ohm meter, you would likely find high resistance or open circuit on a bad coil.

later,
chris

 

Superfords, thanks for the reply. I was kind of hoping DB would post his readings on his good & bad coils too. How many miles are we talking on those failed coils?

Mark