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Rob K
Lv 6
Rob K asked in Cars & TransportationCar MakesVauxhall Opel · 1 decade ago

Vauxhall Corsa - Ignition coil question - can you help, please?

I think the ignition coil in my Mum's Corsa is faulty.

I have followed the Haynes manual to determine the short / open circuit condition of the test points. Unfortunately it doesn't give the expected measurements.

Between any Low Tension (LT) point and the body of the coil is open circuit - infinite resistance as expected.

Between the two LT points (primary coil) is a few tenths of an ohm as expected.

Between any LT point and the HT pin (secondary coil to the distributor) is open circuit - Haynes says this should be a measurable resistance and not infinite as I have measured.

Can someone with Vauxhall experience tell me if I need a new coil (or even a second hand one from a scrapyard - I'll test the readings first before buying) or even what the readings should be, please?

Many thanks.

Update:

Sorry, forgot to add that it's a 1995, 1.2 Merit.

Update 2:

Thanks, Cosmic-Angel, the distributor, leads and rotor arm have all been changed in the past. Unfortunately no-one in our neighbourhood owns a similar model of Corsa so I cannot check it.

Update 3:

Thanks to the all who have answered so far.

B, there is a spark but I suspect it's the quality of the spark that is in question. Once the engine is warmed up, it's fine. Since the engine heat will help the petrol air mix towards flash point, a weak spark will still ignite it okay.

It's just when it's cold, the weak spark will not work as well.

Dave - what a great link! Many thanks!

Sleeper, it's most likely the original part and your answer may have identified the fault. I'll try a local scrapyard for a part and if it fails the test, I have Dave's link to get a new one.

Thanks folks!

Any other answers are welcome!

Update 4:

Dave, I meant to add... Vauxhall are looking for £54 for a replacement coil... paid in advance because it's not a stocked part... can you believe it?

Update 5:

Theone... can you offer a bit more info on this please... I have discovered something called the ignition amplifier module and I'm wondering if this is faulty...

To everyone else, it would appear that the coil is in fact working within tolerances...

I didn't use the auto-ranging multimeter and had to do a manual adjustment... oops!

Update 6:

Have tested two coils.

LT to casing - open circuit - expected.

LT to LT - very low resistance ~0.1ohms - expected.

LT to HT - 6k38 - 6k75ohms - expected.

Now suspecting ignition module...

7 Answers

Relevance
  • theone
    Lv 4
    1 decade ago
    Favourite answer

    ever think it might be the ignition module?!?!?!?

  • Anonymous
    1 decade ago

    Has the coil been changed before.Vauxhall going back some always used ballast resistor with 9 volts,and if a 12 volt alternative has been put on it overpowers the ignition circuit eventually.Long time since i did them but its only an idea.

  • ?
    Lv 4
    5 years ago

    If there is oil in the spark plug recess it has the two dropped on it from above or come out of the cylinder previous it, (which isn't likely). in case you had the automobile serviced and that's working on 3 cylinders once you purchased it lower back take it lower back to the place it become serviced and tell them to make certain why that's purely working on 3 and if it become their fault to repair it. Compression try is recommended. There would properly be various motives why one cylinder isn't firing and with out an inspection we are able to`t enable you already know the respond in spite of the undeniable fact that that's because of low compression or electrics. If the problem remains working a broken cylinder is an no longer likely yet a threat answer, as I even have suffered 2 situations in the final 40 years the place a hollow in the area/suitable of a defective piston has led to tension in the crankcase to blow oil out of the breathers after severe mileage and spray multiple oil surely everywhere, yet your problem doesn`t look as severe as that, i'm hoping. wish you each and all the superb, Bob.

  • cosmic-raphael
    1 decade ago

    If you know someone with a corsa, try there coil first, just to check that it is the coil and not anything else like the a cracked distributor cap.

    Atleast that way you know for definate before you by the coil.

  • Anonymous
    1 decade ago

    doesnt need to be a corsa coil to compare with, try another car, yes the readings will be slightly different but not that much.

    or why not pull all the spark plug leads off and Put a spark plug in one of the leads to see what happens

    note which lead came from where and hold lead with insulated pliers and hold body of plug to chassis of car

    if the car runs i doubt its the coil, may be the points

  • dave
    Lv 4
    1 decade ago

    A new coil is £14.50

    Testing is very nice but there is no substitution for, well, substitution.

    http://www.electricalcarspares.com/xref.php

  • Anonymous
    1 decade ago

    your best bet is to get a new one,atleast you know it works

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