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Coil pack plug


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My car isn't starting (2L Zetec, FI), even after a new battery.

To check for spark, I used these little gadgets that plug into the HT lead and then onto the spark plug and flash as you crank the engine. On cylinder 1, it was not flashing. I checked resistance and then swapped out the HT lead and the coil pack - no luck.

I then checked the voltage on the coil pack plug and found that, with the ignition on (before cranking), I am seeing 11v on ALL 3 pins? This doesn't seem right but maybe it is - can anyone confirm?

My car last started about 2 weeks ago AFTER a bit of a re-wire, although I did have to jump start it from another car, hence the new battery. The re-wire did NOT involve the coil pack directly, just aux panel 12V plugs, horn etc but who knows with damn electrons...?

Also, even with the new battery, the starter motor sounds pretty lethargic (it is relatively new, so can't be an age problem) - would a dodgy earth (seems to be the most common cause of electrical problems 🙂 ) cause that?

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To answer your coil pack question.  I think that I have found the circuit diagram, for the "Wasted Spark" pack used with Zetec ignition systems:-

edis2.jpg.6ef0f9e816e45f95df21808ef458e136.jpg

I assume you are measuring the voltage between 1,2,3 and a good earth (-ve). Pin 3 should be the same voltage as is coming from the ignition switch (terminal 15), I would have expected 12 volts. Pins 1 and 2 will be almost the same voltage as pin 3 because the primary windings are not big resistances. Also you say that only one cylinder seemed to have no spark ?. This would be unusual with this pack, as two HT leads should spark at the same time. One for a cylinder at top of compression and the other at top of exhaust.

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Ah, that diagram explains the same voltages on all 3 pins,  although I don't get how the coil pack works then? But that's not important right now...

Yeah,  I expected cylinder 4 to not fire as well but it did. I suspect the dodgy little devices I'm using,  although I did try 2 of them on cylinder 1.

Ok,  I think I'm looking at a starter motor problem - it's just too lethargic.

Edited by nelmo
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At the risk of seeming patronising, it is essential to have good connection for the thick power cables that are used to feed the starter motor. Disconnect the battery at the negative terminal and follow the path of the connections from the positive terminal to the starter motor. I would pull apart each connection that is not permanently joined and clean the mating surfaces until bright and shiny before rejoining. Then smear vaseline on the outside to ward off dampness. Then do the same for the path from the starter motor back to the negative of the battery. This may well include a good thick "Earth Strap" between the engine block and the battery -ve, and the chassis and the battery -ve. Apologies if this is obvious and I seem to be stating the obvious.  The other thing that is interesting in your account, is that you have spark at all but one cylinder and yet the engine shows no sign of starting ? at all?  so how have you ruled out no fuel?

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Not patronising at all - I'm going to do what you suggest next. 

I think the non-flashing cylinder 1 was maybe just a red herring - I was cranking the engine and trying to see in the cylinder at the same time - maybe i just missed it? Ruling out fuel only because I have a clear filter and I can see petrol moving and I can smell it. Also,  car started and ran fine 2 weeks ago. But will reconsider if i can improve the starter motor performance and it doesn't help. 

Also, it occurred to me,  I changed the battery and maybe that has wiped my map out of the ECU. I did have an updated map which has altered injection figures to help cold starting, so another thing to check.

Edited by nelmo
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On 12/15/2020 at 7:54 PM, nelmo said:

Is that the main power light? The ECU is working because the fuel pumps come on. 

There's a light on the ECU which comes on when it gets a signal from the crank sensor. If it doesn't see this signal, it won't start. Fuel pump will prime regardless of the crank signal.

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16 hours ago, nelmo said:

Re-read line 1, post 1 🙂

 

Doh, have checked the voltage across the battery terminals? If that’s 11v then it’s a battery issue. If it’s significantly more than the voltage at the coil plug it’s a loom issue. 

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Urghhhh, Ok, for future reference, disconnecting the battery wipes the map from an Emerald ECU and sets it back to the default. So I'd lost all the cold start modifications Emerald (and Dan from on here) gave me. 

I've got them saved so reloaded them but the battery still hasn't got the oomph to turn the starter motor enough to go for a start. So I'll do the terminal cleaning as described by Spare part next - hopefully that will sort it - and I hope I haven't killed my new battery 😞

 

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4 hours ago, richyb66 said:

Never had an issue with Emerald loosing maps on a battery disconnect. I wouldn't be convinced this is the issue.

I connected the laptop up last night - it had definitely reverted to the base map. I had this starting problem a year or so ago - Emerald sent me an updated map with some ignition/injection changes which worked a treat.

My starter motor has been getting progressively slower since then but it's always been ok to start the car. I had a big gap of 2 months without driving, which I guess mostly killed the old battery so that and the cruddy starter (hopefully just connections) prevented starting.

Now, I've replaced the battery but the combination of crud starter and base ECU map without the cold start enhancements explains my current situation?

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