Mondeo Weak Spark

Mondeo spark plug leads pack up at every 35-40,000 miles. Whats the=20 mileage on it? Impedence can be fine but if the insualtion has started=20 to break down...

--=20 Conor

Hi. This is my friend, Jack Shit, and you don't know him.

heart-stopping

Symptoms shout coil pack, I'm afraid, although if leads are old you will need them anyway. Also duff leads can cause coil pack failure.

1. Renew leads/spark plugs unless very recent.
2. Replace coil pack.

MrCheerful

heart-stopping

When were leads replaced on this machine last? They are good for around

35-50k miles only. If they are of abit of age, replace them. Genuine or Bosch only.

If you still have same problem, then coil pack is internally shorted, which they do occasionally.

Reading your symptoms I would probably go straight to the coil pack after examining the leads, however as they are cheaper, and a wearing part anyways, do them first.

If you have the plugs out- re gap them to 1-1.1mm not the suggested 1.3mm- it gives the ht components an easier time.

As you have discovered the coil pack on these engines is incredibly powerful. Be wary working on it with the engine running as the shock apparently is very nasty, possibly life threatening...

Tim..

Guys,

Thanks for your advice.

The thing is, I really expected it to be HT lead No.2 that was duff, so I checked the leads first. I've actually got the same car as the missus, so I swapped my HT lead No.2 into her Mondeo, with no difference in the results.

So then I tried removing each HT lead in turn from the *coil pack* end, and (carefully) placing a long screwdriver across the top of the coil pack, over the open connector for that cylinder.

Bugger me, the spark was capable of jumping the gap between the internal contact and the tip of the screwdriver - almost a 2-inch gap!

At that point I started having kittens, and made a pact with myself that I was going nowhere near that bastard with the engine running. I would say that the coil pack was probably capable of producing in excess of 30kV.

Like I said, 'heart-stopping' stuff.

Today's project is to install the new coil pack. Cost: about £50 from Henry.

Fair point about the leads, guys: will replace those too.

Thanks again,

Alan

Thats some bloody spark !!!!! Are Mondeo coil packs adapted from electric chair components or something ????? I would be terrified to go near it without a chair and a whip.

More like 45kV to 50 on a good one. They are immensley powerful, which is why you can appreciate that the leads must be of absolute quality, clean and dry if you arent to get the insulation breaking down.

Anyways, from what you have said today- I would put money on you have an internal short in the coil pack.

Tim..

Well,

I fitted the new coil pack this evening, and once again it ran perfectly. Big fat sparks on all four cylinders!

I will get the missus a set of Ford OEM HT leads and bang those in too. I'm wondering if a gradual breakdown in the integrity of the HT leads (particularly No.2 lead) has caused premature failure of the coil.

Strangely enough, there were no cracks or signs of physical damage on the oil coil pack. Must be, like you say, an internal short. Unusual, tho...

Thanks again guys for all your help.

... Now, if I could only get the 'jerky' problem on my '97 Ghia X sorted.... !

Regards,

Al.

Usually you get a break down on no.4 lead and it shorts down the plug nose in 9 times out of 10 cases. Occasionally I have seen the HT tracking accross the coil pack surface from no.1 to number 2.

Its not very often they short internally, but yours did!

Whats the problem with the Ghia X?

Tim..

Hi Tim,

Well, my Ghia X is actually identical to the wife's (sad, but true); except that mine is of very early Mk.II vintage (September 1996); hers is mid-1998.

Whenever throttle is applied or cut, particularly in the lower gears, the car 'bounces' - a bit like old, small, girlie cars used to do (does this ring true? - small Fiestas and the like!)

Example: 2nd gear: apply (reasonable amount of) accelerator - bounce, then takes up drive. Off gas: bounce, bounce, bounce... steady.

It's both annoying and embarrassing, because it looks like it's bad driving style! The only thing I can think of is that it had a replacement MAF sensor on the air intake, round about the time that these symtoms started.

The engine idles smoothly in neutral, so I'm kind of lost for ideas. Except that if I allow it to coast in 1st or 2nd gear at idle speed, it will become very 'bouncy' - presumably as the ECU instructs the engine to raise its revs. But in the missus's 1998 Mondeo, I can coast in 2nd at idle speed without her car protesting.

I've not been able to diagnose this one for love nor money; it's been going on for about a year.

Thinking of selling and getting a 2.3 or 2.9i Scorpio ...!

Any ideas? I've more or less given up on this one!

Cheers

Al.

[snip]

My Escort Zetec does this too. FWIW I have always been under the impression that it's the clutch doing it's job - ie smoothing the power spikes reaching the gearbox and knackering everything. Mind you, it's also been drinking fuel like it's going out of fashion, but I think that's a separate problem entirely.

Perhaps the idle speed in that car is ever so slightly higher than in yours? Remember also that there are likely to be many detail changes between the 2 cars, so they will never drive exactly alike.

Sorry no. Do what I'm going to do and take it to a reputable main dealer or auto electritians so they can run a full diagnostics test on it.

Robert