welcome to the jet

 

Let's see if someone in Team Tech can better answer this question

 

Well I don't know about ohm readings, but you could buy a spark tester and hook it into each plug terminal to verify that it is sparking.

Do you see some fouling on the spark plugs or are you having some other cause that would make you think you need a new coil?

 

Haven't pulled the plugs yet. I'm going to be replacing my spark plugs and wires, and looked up the ignition coil in my Haynes book. Haynes says remove the coil and test the resistance on the primary and secondary coils. I think it says .4-.6 ohms for the primary, and 10,500-16,500 ohms for the secondary. But it does NOT say which points on the coil are used to test the primary and secondary coils. However, I have seen that between the points for cylinders 1 and 4 I get about 12,000 ohms, and between 2 and 3 I get about 12,000 ohms. Between the others I seem to have an open circuit. It surprises me that there is continuity between two different wire connectors... wouldn't that cause both cylinders to fire? Obviously not I guess, but I still don't get it. I guess the resistance is large enough to prevent spark?

I'm tempted to replace the coil just because it's got 128,000 miles on it and my car has a bit of roughness and it seems like a likely opportunity for improvement. However, I don't want to waste 60 bucks for no reason. That's why I'd like to test it.

 

Oh, and on a related note:

I broke the little tabs on the coil that hold the wire connector harness on. What is the proper way to remove that connector? Because apparently I'm missing something.

 

There's a useless wire(think like paperclip) loop underneath the plug. Push it up, then slide the plug out. I broke plug once doing the same thing.

At this point, if the tabs are broken on the coil, just replace it. At an interval of 130k, I wouldn't worry too much about throwing money away, more so just regular PM.

If you do break the harness/plug, order a repair kit from Steve @ tousley, I think it was around $40-50.

 

Thanks.

Just got off the phone, ordered my parts from Tousley Ford (FORDSVTPARTS). Even with the shipping cost they saved me money over my local dealers! :thumbup:

 

Yup, great guy!

 

I changed my plugs, wires, and coil yesterday... It's like a totally new car! I can't believe the difference it made. I've been meaning to post about some running issues I've been having, but they were so bad I hadn't yet figured out how to describe them. They're gone now! I think I spent about $100... feels like I just dumped $5k into my car!

 

Just for some information, it does fire both cylinders at once. One is on the compression stroke and get fired, the other is on the exhaust stroke and the spark happens but is "wasted" because there is no fuel mixture in the cylinder.

 

The coil pack has two separate primary/secondary systems in it. Each secondary fires two plugs in a series circuit arrangement, as gregmatic states above. The two primaries are fed battery power on a common lead, with their firing accomplished by ground pulses delivered by two separate leads, one to each primary, coming from the PCM. A similar system, firing two plugs in series, was used on Harley Davidson motorcycles for many years (and may still be, for all I know).

 

can someone tell me which tabs are the primary and secondary on my ignition coil?

 

A few years back in my Ford Focus FFV 2003 had a faulty coil pack and I had it replaced. Now the ignition is acting up again and this time I would like to attempt to repair it myself. A stroboscope indicated that all four spark plugs fires off. I checked the spark plug electrode spacing; all them are 1.3 mm as they should and they generally look healthy. The resistance in the ignition cables are all in the low kohm range, depending on their length.

Now for the coil; my multimeter gives me 1.2 ohm for the primary circuit (measuring between the outer two of the three connector pins on the side). Measuring between the middle pin and any of the other two gives me 0.7 ohm. The secondary circuits (between 1 and 4 and between 2 and 3) both give me 10.46 kohm. Is my coil pack faulty or not? Or am I measuring between the wrong connectors?

Any ideas?

Thanks in advance!