Ford Fiesta - 1999 fiesta not idling properly and Misfiring too | Technical matters | Back Room Forum

Sat 14 Mar 2020 04:22

Ford Fiesta - 1999 fiesta not idling properly and Misfiring too - Karen LB

Hi I’m in need Of some help/advice please!!

I have a T-Reg 1999 mk4 ford fiesta Zetec-S 1.25 16v

At the moment my car is not idling very well and it also has a misfiring problem????

I have changed all the spark plugs and I have also put a new set of ignition leads(HT leads)on too!!

Although this unfortunately has not made any change to the performance of my vehicle with regards to the idling situation nor has it had any effect to the misfiring situation either????

I have recently been advised that I should maybe also try changing the ignition coil pack....which I have purchased!!

But unfortunately this is where I’m now stuck as I can’t seem to find any information or advice on the internet about how to change the coil pack on the mk4 fiesta model-which was manufactured between 1995-2002....I can only find information/videos on Mk5/6/7 models-which are 2002-present

I really hope that someone can shed some light on this situation for me please

Many Thanks In Advance
Kaz

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Sat 14 Mar 2020 07:46

Ford Fiesta - 1999 fiesta not idling properly and Misfiring too - paul 1963

Hopefully the Doc will jump in and offer advice but in case he doesn't get your self a Haynes manual.

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Sat 14 Mar 2020 08:27

Ford Fiesta - 1999 fiesta not idling properly and Misfiring too - elekie&a/c doctor

If you have changed the ht leads ,then you are half way there. The coil pack sits at the opposite end to the spark plug rubber tubes. Secured to a bracket on top of the engine . It may be attached by 4 torx screws.

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Sat 14 Mar 2020 14:17

Ford Fiesta - 1999 fiesta not idling properly and Misfiring too - thunderbird

Coil pack is bolted to the head at the gearbox end, its obvious since the HT leads connect to it..

Carefully make a note as to which lead goes where before disconnecting them, the coil pack is labled but a photo on your mobile makes life easy.

There are 3 torx head bolts holding it on, 2 at the top and one under.

Then there is a multiplug form the ECU, will only fit one way.

Refit in reverse order.

Simples.

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Sat 14 Mar 2020 15:23

Ford Fiesta - 1999 fiesta not idling properly and Misfiring too - Railroad.

The ignition coil pack is actually two coils in one unit. One coil fires cylinders 1 & 4 and the other fires cylinders 2 & 3. As long as this pairing is correct it does not matter which lead goes where. Eg. 1 & 4 are interchangeable and so are 2 & 3. This is known as a wasted spark system.

The other thing that could be the problem is a vacuum leak. By the inlet manifold are 2 vacuum hoses. Take a good look to make sure they are not damaged, deteriorated or split. If they are they will cause a misfire most noticeable at idle.

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Sat 14 Mar 2020 17:02

Ford Fiesta - 1999 fiesta not idling properly and Misfiring too - thunderbird

The ignition coil pack is actually two coils in one unit. One coil fires cylinders 1 & 4 and the other fires cylinders 2 & 3. As long as this pairing is correct it does not matter which lead goes where. Eg. 1 & 4 are interchangeable and so are 2 & 3. This is known as a wasted spark system.

Agree with this but a bit irrelevant since the plug leads are all different lengths and will only go to specific plugs, if I remember correctly they are actually numbered.

The other thing few owners (and even Ford mechanics) are aware of is what Ford did to genuine Motorcraft Platinum plugs for these engines. The original plugs in my 1998 engine had 4 identical plugs which could be fitted in any cylinder. Later engines and replacement plugs only had a platinum tip on one part of the plug, of the 4 plugs 2 were different to the other 2. I took my set back thinking it was a duff set and was told not to worry and fit them anywhere which I did. Then I did a Google search and found an answer on a kit car site that gave exact details about where to fit each specific plug, cannot remember the answer, sold that car in 2008. But they did say that the average owner would be unable to spot any difference but the life of the plugs would be less when fitted in the wrong cylinder.

And all because Ford wanted to save a few pennies a plug.

Edit

Done a Google and found the answer. The Motorcraft plugs supplied are two off AYFS22P1 and two off AYFS22PG1. The correct position for each type is from the timing belt end P1 / PG1 / P1 / PG1.

How daft is that.

Edited by thunderbird on 14/03/2020 at 17:12

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Sat 14 Mar 2020 20:56

Ford Fiesta - 1999 fiesta not idling properly and Misfiring too - Railroad.

Probably not daft at all. Remember the old Citroen 2CV? The engine was a 650cc air cooled twin. It was the first car to use a distributorless ignition system. It had a double ended coil switched by a set of contact breaker points operated off the crankshaft. As both spark plugs fired at the same time it was found that the positive electrode would wear on one plug and the negative would wear on the other. On a damp morning when they wouldn't start a usual trick was to remove the spark plugs and swap them side for side. They would nearly always then fire up straight away. The system used on Fords is not a million miles different.

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