Tested my coil pack, tell me what to do?

[Tony91Sport]

Ok, I checked my coil today. I tested across the prongs where the harness plugged in (primary resistance). Haynes manual says it should be .3 to 1.0 ohms. All prongs read .6 Great. Then I go to check the resistance between the corresponding plug wire outputs (secondary resistance). These were to be between6.5 and 11.5 ohms. All of mine tested around 14.5 ohms.

What do you guys think I should do?

 

[Tony91Sport]

Ok, well I called my local Ford Dealer (theyre open till midnight ) And told him of my readings. The service technicial theyre said the It was probably ok because it was only a small amount off, and they haynes manual probably didnt test in ideal conditions. So what id like some opinions from you guys.

 

[IgotTwo]

Well, do you have a good DVOM?
If you have an auto ranging meter, they can sometimes through off a bad reading. Turn off the auto feature. Chiltons 7X24 customer service "ignition car chat" has a blurp on that and some words that "True RMS DVOMs meters can get off false readings.
I have a good DVOM but I double checked mine with an analog before I replaced mine. I had bad primaries and about same readings on secondaries.

Anixous to buy a coil? Are you sitting down? Mine was $130 something on my 97. Conventional wisdom says replace wires with a new coils. $35? So might as well do the plugs too.

Is it not runinng or running bad? did you do a spark test? or just poking around?

 

[Tony91Sport]

Well, I was originally trying to chase down a knocking/pinging/detonation problem. Now that im getting crappy gas milage I need to figure out whats going on. I just changed the wires and plugs. This helped my knock greatly, but not the gas milage. I have a fuel filter, but havent put it in yet. I think it might be time for a new oxygen sensor. How long are those supposed to last?

I cant say ive put one in in the last 40,000 miles.

Yeah I checked the prices for coils around here too, about 80 from Autozone, 105 from Ford.

Why did you get a new coil? Did it help any problems you were having?

I have a spark tester, but the guy at the autoparts store said it wouldnt tell me how strong the spark was....

 

[IgotTwo]

My 97 dropped dead on highway.. I had a "no start problem" I was careful testing the coil because I just didn't just want to go crazy replacing every and any thing... but the prim tested bad and the secondaries were out of range so that was good enough for me.

I think 40k is OK for the O2 unless something else is going on. (you have some problem where the thing is fouled up with crud.) I replaced the O2s on my 94 at 84K as PM. But it did run a little better especially at idle.

The 97 is the eec-v system which is the distributor less My coils may be a little more pricey.

I'm not up on the 91's but I think you have an ignition voltage coil that signals the timing advance. I'll defer to great minds but that may be something to look into if you are "knocking".......... maybe a bad timing signal to the puter.

 

[TPLYNCH]

I'd replace (or at least test) the Fuel Pressure Regulator before doing anything else.