coil pack test

[burt ragio]

What is a easy & accurate process for testing a coil pack ?

[Marauderjack]

While the car is running unplug the 12 volt plug on the coil and see if you get a misfire or the engine slows and sputters??

If not the pack is most likely bad!!;)

[capt512]

that will only generally tell you if its completly gone, if its going and only sometimes not as it should be you need to hook it up to a computer or the easier route have it load tested at the dealer

[justbob]

Go from 0 to 90 as smoothly as you can with constant acceleration. This is the approximate time it takes to throw a MIL for specific cylinder misfire so I have been told.

[EMAS]

You can use an ohm meter to check the resistance of the primary and secondary circuits, sorry I don't know the specs for our coils off the top of my head. That unfortunately doesn't tell the entire story, to know that you need to use the Ford load tester that simulates a running condition.

Are you looking to test the coil because you have a cyl miss-fire related code? If so the quick and easy test is to swap the coil from the cyl that has the code to another cyl, clear the codes and see if it moves to the new cyl.

[burt ragio]

I was looking to test the coils because a lean condition came upon bank two. The engine has a very slight shake at idle other than that it runs great. I cleaned the MAF then cleared the code. Thought the next step if it came up again would be to check plugs then coils then change out O2 sensor.

[justbob]

I was looking to test the coils because a lean condition came upon bank two. The engine has a very slight shake at idle other than that it runs great. I cleaned the MAF then cleared the code. Thought the next step if it came up again would be to check plugs then coils then change out O2 sensor.

Check all that you mentioned, plus also a vacuum leak at injector and also for exhaust leak on that side.

[burt ragio]

Vacuum leak at injector ?

[justbob]

Yes. Try running a propane tank around the injectors top and bottom (without a flame...:rolleyes: ) Very common for injectors to leak air in and not seep fuel out. My escort alone had 5 out of 8 orings creating vacuum leaks and it only has 72,000 miles.

[RF Overlord]

Can't find anything in the FSM about ohm readings for coils... will keep looking.

[Marauderjack]

I was looking to test the coils because a lean condition came upon bank two. The engine has a very slight shake at idle other than that it runs great. I cleaned the MAF then cleared the code. Thought the next step if it came up again would be to check plugs then coils then change out O2 sensor.

If you had enough of a misfire you'd be rich not lean.....may have a sticky injector or two not delivering enough fuel?? :confused:

Try some SeaFoam or Chevron injector cleaner in you gas!!:beer:

[burt ragio]

All this is great info that I realy appreciate. Knowing what I now know I should 1st change my fuel filter & add some injector cleaner to the gas tank. 2nd should a lean code come up again check for vacum leaks & at injectors. Last check plugs & coils since they would have nothing to do with a lean code ?

[EMAS]

If you had enough of a misfire you'd be rich not lean.....may have a sticky injector or two not delivering enough fuel?? :confused:

Try some SeaFoam or Chevron injector cleaner in you gas!!:beer:

No a misfire causes the O2 sensor to indicate lean. As the name implies it reads the oxygen content of the exhaust, nothing else. So if the air/fuel mixture doesn't ignite then the O2 sensor sees all that unconsumed oxygen and gives a lean reading.

[yjmud]

if you are missing and lean check for un-metered air getting in the engine + check the fuel psi

[EMAS]

if you are missing and lean check for un-metered air getting in the engine + check the fuel psi

Usually un-metered air will cause both front O2 sensors to show lean, not just one.

[Marauderjack]

No a misfire causes the O2 sensor to indicate lean. As the name implies it reads the oxygen content of the exhaust, nothing else. So if the air/fuel mixture doesn't ignite then the O2 sensor sees all that unconsumed oxygen and gives a lean reading.

I still say a misfire and unburned fuel will show up as RICH....especially if a vacuum leak will show up as LEAN!!

I'm no expert here but what you say above makes no sense to me??:(

[EMAS]

I still say a misfire and unburned fuel will show up as RICH....especially if a vacuum leak will show up as LEAN!!

I'm no expert here but what you say above makes no sense to me??:(

First consider this; normally when we are talking about a "lean" condition we say it is because there is not enough fuel. However you can also look at as there was too much air (O2) and that would be just as a correct statement. So when a lean condition exists the fuel that was not burnt did not consume as much O2 as there was in the cylinder.

An standard O2 sensor only senses O2, hence the name. It does not sense HC (fuel) CO (partially burnt fuel) CO2 completely burnt fuel or anything other than O2.

So when a misfire occurs that cyl dumps its unburnt air/fuel charge into the exhaust. The O2 sensor senses that excess oxygen and gives the same output as a lean condition regardless of why the extra O2 is there.

I've seen people who were attempting to tune the fuel on a engine with a miss and a lean O2 reading, chase their tails around and around adding more and more fuel while the sensor kept showing a lean condition.

[lifespeed]

While it is not hard to test and prove a complete dead coil has failed, intermittent problems can be maddening.

My own experience with the ignition coils was that I bought one new one from Ford and swapped it cylinder to cylinder trying to find an intermittent misfire. I finally gave up and replaced them all. It cured the problem, car runs great.

I will also comment the part number from Ford was different than the original coils. It is my impression the coils are a faulty design and have a tendency to fail. At least the original design. I have never seen so much discussion of bad ignition coils as seen on our cars.

Ford has made numerous bad electrical pieces; ignition coils, lighting control module, blower motor control.

[T Prok]

the only real way to know 100%

http://www.youtube.com/watch?v=y4r5OcHN5Lg