Author Topic: Coil packs  (Read 717 times)

January 26, 2017, 07:26:27 AM
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So I was having misfire issues when giving the car a few beans, particularly in second gear. It would happen when throttle was above about 50% open and boost came in. Only boosting to 0.8 bar at the moment. I changed out the coil packs yesterday with eBay aftermarket parts and only paid 145$ for all 4 landed. SSA is much more expensive.

Notes on doing the job:

Difficulty rating: (compared with swapping a turbo) about 5-6 (because of tight spaces)

Tools needed:
10mm, 12mm  sockets (and maybe a couple of others that I can't remember)
Ratchet extensions to get the airbox out
Maybe a small breaker bar
Screw drivers or small socket for hose clamps
Lead lamp or torch.
I went though 10 nitrile gloves as there are seriously sharp things down there. Wear gloves!

Time taken: about an hour and a half (but I didn't know what I was doing. I think it's doable in 45mins or less once you know how to fiddle things out and in)

First, saw off your hands and sew on some second-hand, tiny ones. I had to search for them as I couldn't find any on eBay (and I thought you could get anything on there). Seriously, the space is very tight and the flexible rubber on the end of the coil is the only thing enabling this job without removing the engine totally.

Start with the passenger side of the car (for RHD cars) as it's more difficult than the driver's side.
You will need to remove the battery and tray (10mm) and most likely the secondary air pump (mine is already deleted so not sure).
The bolts that hold the packs in are 12mm. Can't remember what you need for the air pump.
I started loosening the bolts with a short breaker bar as I couldn't get enough leverage with my little 1/4" ratchet, then switched to the ratchet. Once the bolt is loose enough, you'll have to get your hand down there and loosen it all the way with your index and middle finger as your thumb won't get in there unless you have abnormally small hands or followed the first suggestion here.
Take the front (towards the radiator) coil pack out first and then the rear one, before reinstalling the rear then the front. It makes a little more space to get the rear one in and out. I did take mine out and put it in from the rear of the engine, requiring a couple yoga moves and a remarkable feat of hand/arm contortionism.
When the coil packs are in position, don't bolt them in just yet, first rotate them upside down to get the connectors on then turn them right side up and bolt them in, otherwise you'll just end up unbolting them again.
It will take a fair amount of fiddling to get the packs to their position. I ended up thinking to myself "how in heck did I get the old one out when the new doesn't fit back in!?!?!)

On the driver's side, you'll need to remove the entire air box to get your hands down there.

The car idles nice and smooth and I can push the car all the way up the revs with no hiccups or hesitation. Absolute pleasure now!

I only bled once! Which I consider a real result as I normally need a blood transfusion after checking the oil on this car.

Anyway, check the YouTube tuts for a guide and you're good to go. Not a demanding job but it's quite frustrating getting the packs in. Getting them out is ok.
2006 Forester XT, Wiseco pistons, 18"Koya lightweight wheels, Bridgestone re002, Custom 20g turbo, STi IC, 76mm exhaust, Walbro 255, Custom turbo inlet, intake spacers, Gizmo Boost Controller, TGV deletes. BC RA Coilies, Brembo big Calipers, PB RS Discs, Coolboost WMI, Intent Performance Tuned

January 26, 2017, 04:51:31 PM
Reply #1


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Hahahaha. Nice write up man. I need to find out where my odd lumpy idle is coming from.
Dreading having to change out one coil pack at a time,
Forester XT 2008 MT
TD04, STi IC, 76mm DP, GFB EBC, Coolboost WMI, WHP built and Intent Tuned. Blue Wasabi V3.5

January 27, 2017, 10:22:16 PM
Reply #2


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Very good write-up.

Just to avoid some confusion, the when referring to a coil pack, it's normally that block sitting somewhere on the engine, which serves all the plugs. In otherwords, you will have a HT lead from the pack to each plug.

The ones Garsie speaks about, are the "on plug coils" There is a coil for each plug, fitted onto the plug itself. No more HT leads.
The one major benefit of the latter type, is that the spark to each cylinder can be controlled individually (not sure wether it is actually done). More importantly, the ECU can monitor each plug (spark), and give an error in case of malfunction, which it can't do with the coil pack (i could be wrong here, but it is true for the SG9 Fozzies).
With the correct software, you can actually monitor the misfires on a coil, AFAIK.
The SG9 pre-facelift has a coil pack, and the facelift model coils-plugs.

Furthermore, if one coil-on-plug(aka "Pencil coil") fails, you can replace that one only.
With the coil pack, replacement is more costly.

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« Last Edit: January 27, 2017, 10:27:01 PM by berndp »
Subaru Forester 2005 2.5 Xsel
Always looking for a tar free "road"
Brackenfell, W'Cape