Coil pack failure

[NITROPIXIE]

I thought i would share and put this up here as i was having running problems with my mini. I've been using the flat mounted Ford coil pack from the local scrapyard.

What was happening was on acceleration it would be stuttering and almost felt like a miss fire, well probably was. When cruising it was fine. This has gradually gotten worse, as at first it would only do it under hard acceleration. A friend of mine had a similar problem with his old Fiesta and commented it was down to the coil pack so i tried and sure enough problem had gone.

Other symptoms of this is that my shift light was faintly coming on when the engine was stuttering. This seem to have rectified itself too now.

Just for information i have found the flat mounted coil packs can be found on:-

MONDEO'S - 1998 TO 2001 1.6/1.8/2.0 16V ENGINES
FOCUS - 2004 1.4/1.6/1.8 PETROL ENGINES
COUGAR'S 2.0 16v
KA'S 1.3 98- ENDURA AND DURATEC ENGINES INC STREET KA
FIESTA'S 98-2004 1.25 1.3 1.4 1.6
FUSION'S 1.4 1.6
ALL FORD PUMA'S 1400 1700 ENGINES
ALL TRANSIT CONNECT'S PETROL ENGINES

[cng1]

Your experience is very interesting as the number of coil pack failures that we see is very low indeed, however we almost exclusively supply the 1st gen coil packs, rather than 2nd gen one that you have.

What we have seen is that a lot of workshops, when presented with a problem like yours, replace the coil, plugs and leads as a matter of course as it's a cheap and easy thing for them to do that gets them a nice profit and for one reason or another the problem goes away. Often the problem is simply that the leads aren't connecting properly and that simply cleaning up the terminals and refitting them would have cured the problem or that the wiring to the connector to the coil pack is damaged and simply wiggling it around improves the connection just enough for the problem to go away for a while. That's not to say what the workshops/dealers do is the wrong thing to do - many times replacing the full set of parts works out cheaper than the labour costs for a more in depth diagnosis but it is worth giving all your components and wiring a good wiggle/clean to see if you have got the problem completely nailed.

There are two main things to check for on the 2nd gen coil packs, one is corrosion/breakdown of the terminals inside the towers - from time to time we've seen the pins completely dissolved by water getting in and we've also seen the pin burnt/erroded away due to arcing because of a poor contact. The other thing to look for is the connector wiring on the coil pack if you are using a second hand connector. The sheathing on the wiring used on Euopean cars becomes stiff and brittle over time, eventually cracking and allowing water ingress. This causes the copper to corrode and the split in the coating causes the strands to start work-harden and eventually break. If you see cracks or splits splits in the sheathing or any green, grey, black or white powdery residue on the copper wires itself when you soldered the wires together (which would have made tinning the ends very hard for you) then you should bin the connector and chop your wiring back to a point where it is still nice and flexible and has good clean copper inside. We keep replacement connectors and pins in stock (likewise the coil packs themselves) so there is no reason not to fix the problem properly with new wiring and a new connector.

[NITROPIXIE]

Wow, i've never seen the coil pack pins corrode away due to arcing before. My coil pack itself looks physically in a good condition. All the connectors look fine, but i haven't been able to continuity test the coil pack yet as my multimeter battery has gone. I'll keep an eye on the multi connector to the pack thanks.

I've been double checking the leads and changed the plugs, but didn't really suspect the coil pack as they normally last an age, guess i shouldn't buy scrap parts, false eonomy lol.

I have come across the different states of wire corrosion a few times, black rot as i call it and copper wire turning into green/white powder, happens most often on cooling fans circuits i find. I amaturely work on cars for a hobby, done a megasquirt install aswell which took a while aswell as numerous head gaskets and regular maintenance. Helped do a nut and bolt rebuild on a TR6 and love getting my hands dirty.

Thanks for the pointers and will keep you in mind for connectors and such.

[NITROPIXIE]

Are you supposed to change to resistive spark plugs when using coil packs, or is it better without?? ie NGK BPR6ES or BP6ES for instance.

I'm sure i remember reading that resistive plugs were better as they reduce electronic noise to the igition system electronics??

Only my problem what ever i have doesn't seem to want to go away. I'm sure its a mixture/fueling problem which is then being followed by an ignition problem once all the plugs have gotten black and causing running issues. I tried cleaning the plugs but the problem persists. I have tried a different array of coil packs and leads and the problem stays. Its frying my head at the moment, lol.

I've currently got my cylinder head off. I'm going to get it skimmed then I will compression test the engine once the head is back on to prove all the bores are good. I have a couple of small scratch marks in one of my bores which is worrying but will see what the compression test indicates i guess. If its good then i shall put it back together with fresh plugs and get it running again, then straight off to the tuners.

[cng1]

Yes, you absolutely must be running resistive plugs. Whilst the EDIS modules are very good at resisting noise the non "R" versions are very bad news indeed.

If you haven't already I would try swapping out your plugs. Cleaning them or baking them in a blow-torch sometimes is enough to restore them but once they've got properly wet with fuel and caked in soot they're never quite the same again. For the sake of 10 quid for a set of plugs I'd swap them out if everything else checks out.

[NITROPIXIE]

I thought they had to be resistive, thanks.

£10, lol i never pay more than a fiver for some NGK R, Halfords trade card works a treat

[brentp]

I've experience a marginal coil pack where the leads on the High Voltage connection inside the coil pack had broken. Evidently it was sparking across the plugs *and* inside the coil pack.

The problem manifested itself as a miss under high RPM / high boost. Accompanied by massive flames from the exhaust!

After I corrected the problem- the engine ran much better. Yet, flames went away.

I was sad

[NITROPIXIE]

I've done a continuity check between on the HT and LT sides of the coil pack and there was nothing unthwart. I guess the coil pack has degraded and just can't cope when in use.

Anyway new coil pack and plugs to come.

[DannyP]

Just so you know, I've been using NGK DP8-EA9 plugs in my engine since 2005, when I first fired it up new. Megajolt 3 for two years now, no problems. Accel EDIS4 coil to fit USA Ford Escort.