Legacy 2 litre ignition fault

[yewman]

My 1999 Legacy 2 litre started running rough. I fitted new plugs and swapped plug leads with no improvement.

I then connected an old strobe light between coil pack and plugs, and found one cylinder had no spark. I assume that the coil pack is faulty., but can I check it out with a meter before spending loads on a new pack.

I have read various posts talking about ignitors.I have no idea where these parts are, or how to check them.

UK legacy's have on board diagnosis, and all this shows is fault code 12, ignition circuit.

Thanks

[lmdew]

Most Subaru coil packs fire 2 plugs, 1&3 or 2&4.  

 

Did you try swapping plug wires?

 

Did you use Subaru or NGK Wires?

Copper Core Plugs? NGK

[yewman]

The wires are fine. The plugs are new NGK. This coil pack fires all 4 plugs.

 

As I said, there is no spark coming from the coil pack on one cylinder only..

I checked this by fitting a strobe light which lights up every time the plug fires.

 

What about these ignitors, how do I find them?

Thanks

[TOONGA]

The igniter / ignitor is on the firewall of the car as in this photo

 

 

from this thread http://www.ultimatesubaru.org/forum/topic/80582-subaru-legacy-ej20/

 

As you are in the UK it will be on the right side of the car not the left as in this picture of a left hand drive vehicle.

 

I'm thinking it is either your coil or you ignition relay as  an igniter / ignitor either works or doesn't

 

You can pick up a coil pack from Ebay for about 10 Quid

 

http://www.ebay.co.uk/itm/Subaru-impreza-V3-4-coil-pack-/291332715257?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item43d4c872f9

 

 

 

TOONGA

[Fairtax4me]

The igniter only controls halves of the coil, front half and rear half. The coil always fires the plugs in pairs. Front two then rear two. It can not fire one plug idividually. The igniter cannot make the coil fire one plug idividually.

 

 

If you have one cylinder with no spark, it's either the spark plug or the wire going to that cylinder. You have new plugs so we can check those off the list. If swapping wires side to side, and the misfire stays on the same cylinder, it could be an internal break in the coil.

Check that coil terminal for continuity to the opposing side.

[Gloyale]

Most Subaru coil packs fire 2 plugs, 1&3 or 2&4.  

1&2 (front)

3&4 (rear)

 

 

The igniter only controls halves of the coil, front half and rear half. The coil always fires the plugs in pairs. Front two then rear two. It can not fire one plug idividually. The igniter cannot make the coil fire one plug idividually.

 

 

If you have one cylinder with no spark, it's either the spark plug or the wire going to that cylinder.

 

I have seen once....On my own car, a coil where only one post goes dead.  The other side of the same coil still fired, and the other coil too.  So it can happen.  It's the only EJ coil failure I've ever seen.

[yewman]

Thanks for all the useful info.

I am 100% sure it is neither the plug or the plug wire.

I have swapped the wires from cylinders which do fire, and the fault is still there.

Also the old fashioned strobe light which we used to use to set the ignition timing accurately on cars with mechanical distributors actually replace the plug wire completely when installed, and there is no light, so no spark.

 

The reason I thought it was not the coil pack is that the resistance between pairs of coil / secondary terminals is the same on both sides of the pack.

Sadly, the local scrappers have no Subarus. Probably a testament to their superior reliability even when old.

 I am hoping for a cheap fix as i have just bought another Subaru Legacy with a lot less miles and don't want to sell the car I have had great service from for spares.

Thanks Toonga for the cheap coil on Ebay.When i searched for Legacy coils, the cheapest was £30 .

 

All the best for Christmas to all you Subaru people

Yewman

[yewman]

Have checked it all out again, and now I know that each half of the coil pack fires 2 cylinders, sparks on 3 cylinders means faulty coil pack. Have one on order.

Fault finding abandoned for the day.

Ready for the log fire now.

[Olnick]

Beautiful scene.  Enjoy that log fire!  Good luck with the new coil pack.

[mzop]

Think my ignition coil may be bad, not getting and resistance when checking male pin connectors for primary resistance. Getting about 12k ohms when checking secondary resistance, Think i should be getting 18k. So these figures indicate a bad coil?

[Fairtax4me]

Did you check resistance across the output posts? Infinite resistance from post to post means there is a break in the secondary circuit.

 

Primary resistance will be center pin to either of the outer pins on the plug.

Resistance of the outer pins to each other should be infinite.

[yewman]

I have now fitted another coil pack obtained from a breakers yard.

Problem solved, engine back on all 4 cylinders.

The original 4 plug leads/ wires are still fitted

As Gloyale said , 3 out of 4 sparks is possible from a faulty pack.

Thanks

Yewman