Subaru EJ20 slight misfire - cured
Discussion
A couple of days ago, the trusty Forester started misfiring a bit when cold - noticeable because it always runs so smoothly normally..
I suspected a combination of cold and wet had exposed some weakness in the electrical system but the misfire all but disappeared when the car was warmed up.
Had a quick look under the bonnet and checked the obvious bits but nothing apparent so thought it might be a trip to the garage but an intermittent fault with no warning light always means a potential waste of time and money.
So, this morning, checked the internet and as suggested took another look in LOW-LIGHT CONDITIONS ,which revealed that the spark was arcing from the no.1 plug lead across the coil pack (which hadn't been visible before).
Removed the plug lead from the coil pack, cleaned things up a bit and pulled the rubber back a couple of mm, pushed it back on and all is good again.
Hope this might be useful to others
I suspected a combination of cold and wet had exposed some weakness in the electrical system but the misfire all but disappeared when the car was warmed up.
Had a quick look under the bonnet and checked the obvious bits but nothing apparent so thought it might be a trip to the garage but an intermittent fault with no warning light always means a potential waste of time and money.
So, this morning, checked the internet and as suggested took another look in LOW-LIGHT CONDITIONS ,which revealed that the spark was arcing from the no.1 plug lead across the coil pack (which hadn't been visible before).
Removed the plug lead from the coil pack, cleaned things up a bit and pulled the rubber back a couple of mm, pushed it back on and all is good again.
Hope this might be useful to others
Damn! Shouldn't have spoken so soon!
Misfire has reappeared some mornings. A clean and small squirt of WD40 cures it for a bit but then the arcing reappears again😕
Is there some increased resistance due to the coil pack starting to break down or is there some other explanation? Anyone got some advice?
Misfire has reappeared some mornings. A clean and small squirt of WD40 cures it for a bit but then the arcing reappears again😕
Is there some increased resistance due to the coil pack starting to break down or is there some other explanation? Anyone got some advice?
I had the same problem on my Lancer turbo (arcing, it doesn't have coil packs) The only solution was to replace the plug leads, as the rubber had perished to a point of it not insulating anymore, WD40 did temporarily cure the problem,as did Holts "Damp Start" which seemed to spray a coating of plastic over the contacts.
There's talk on Scoobynet of "surefire" coil packs being pretty good, http://www.surefireonline.co.uk/category-s/1883.ht... 150 sovs though, plus fitting on top.
There's talk on Scoobynet of "surefire" coil packs being pretty good, http://www.surefireonline.co.uk/category-s/1883.ht... 150 sovs though, plus fitting on top.
Good luck with that ^. Let us know how you get on.
To update my issue, I could see a hairline crack in the insulation around the no.1 connector on the coil pack and found a new one on EBay for £50 which appeared to be correct and showed as compatible on the menu but ended up having a different electrical connector
However, having taken off the original part, it was apparent that there were more cracks in it than I first thought so, after a bit of searching around, I found the correct part with the right connector also on EBay but for some reason, this was £170!
When it arrived, I put it on and although better, there was still a misfire which got worse over the following couple of days.
After not using the car for a few days, it started to run more smoothly but still not quite right - hesitating under load when uphill / accelerating - so took it into Neil at Slowboy Racing and he reckons that the misfire due to the coil pack has led to a knackered spark plug so I'm just about to replace those to see. Will post again later when I know.
To update my issue, I could see a hairline crack in the insulation around the no.1 connector on the coil pack and found a new one on EBay for £50 which appeared to be correct and showed as compatible on the menu but ended up having a different electrical connector
However, having taken off the original part, it was apparent that there were more cracks in it than I first thought so, after a bit of searching around, I found the correct part with the right connector also on EBay but for some reason, this was £170!
When it arrived, I put it on and although better, there was still a misfire which got worse over the following couple of days.
After not using the car for a few days, it started to run more smoothly but still not quite right - hesitating under load when uphill / accelerating - so took it into Neil at Slowboy Racing and he reckons that the misfire due to the coil pack has led to a knackered spark plug so I'm just about to replace those to see. Will post again later when I know.
Edited by BreakingBad on Thursday 16th February 15:12
Turns out that my coil and HTs are the originals (MY2000 with ~120,000miles) and very tired. This is only based on one 20 mile test drive but the car feels absolutely transformed. All hesitation has gone, including some that I thought were just inherent in the car such as a subtle miss just as it comes on boost.
One thing I don't know for sure is if my coil needed changing at all, as I did both coil and leads together (it was about to rain so I wasn't feeling up to doing half the job then stopping).
Mine is probably due another set of plugs now as well, need to check the records, but for the first time in my ownership it feels like it's running perfectly.
Good luck with yours. FYI I've been using importcarparts.com. They've been really good at advice and they do (the correct) OEM parts at decent prices.
One thing I don't know for sure is if my coil needed changing at all, as I did both coil and leads together (it was about to rain so I wasn't feeling up to doing half the job then stopping).
Mine is probably due another set of plugs now as well, need to check the records, but for the first time in my ownership it feels like it's running perfectly.
Good luck with yours. FYI I've been using importcarparts.com. They've been really good at advice and they do (the correct) OEM parts at decent prices.
Glad you managed to find a cure and thanks for the recommendation for parts - always useful . Those OEM parts were generally pretty durable: pretty sure my coil pack was original in 2000, 110,000 miles ago.
With mine, I got a new set of plugs but when I tried to take the ignition lead off no.1 (the same as the original coil pack issue), the lead just disintegrated! Running the car while the coil pack was failing must have destroyed it. I got most of the bits but a bit of the core was stuck on the end of the plug and I just couldn't shift it. There's really not much room to get at those plugs, is there?
Anyway, couldn't get the old plug out and now had a set of 3 ignition leads plus some scrap. Got the car down to my friendly specialist - Benten's Autocare in Marden - and they managed to remove the bit of core with some weird, long- handled pliers things, change the plug and put on a new ignition lead in about 20 minutes. (Thanks, Clive ) All done and running nicely again.
Well, took rather too long to sort out but gave me the chance to drive the TVR for a few days - which was nice - while it was off the road and decided that it was probably a bit unfair on the poor old Forester to carry on using it as my DD so I've put a deposit down on a STi from Torque GT which should be ready to collect next week, so mustn't grumble...
ETA that I bought the STurbo as a temporary car when we were waiting for another car to be delivered but it has been such a good car, cost peanuts to run (usually), has been utterly reliable and is FUN to drive - not as competent as the Golf R, obviously but the Golf has gone and I have had this old Forester for 3 years now and don't intend to sell it.
. Those OEM parts were generally pretty durable: pretty sure my coil pack was original in 2000, 110,000 miles ago.With mine, I got a new set of plugs but when I tried to take the ignition lead off no.1 (the same as the original coil pack issue), the lead just disintegrated! Running the car while the coil pack was failing must have destroyed it. I got most of the bits but a bit of the core was stuck on the end of the plug and I just couldn't shift it. There's really not much room to get at those plugs, is there?
Anyway, couldn't get the old plug out and now had a set of 3 ignition leads plus some scrap. Got the car down to my friendly specialist - Benten's Autocare in Marden - and they managed to remove the bit of core with some weird, long- handled pliers things, change the plug and put on a new ignition lead in about 20 minutes. (Thanks, Clive
) All done and running nicely again.Well, took rather too long to sort out but gave me the chance to drive the TVR for a few days - which was nice - while it was off the road and decided that it was probably a bit unfair on the poor old Forester to carry on using it as my DD so I've put a deposit down on a STi from Torque GT which should be ready to collect next week, so mustn't grumble...
ETA that I bought the STurbo as a temporary car when we were waiting for another car to be delivered but it has been such a good car, cost peanuts to run (usually), has been utterly reliable and is FUN to drive - not as competent as the Golf R, obviously but the Golf has gone and I have had this old Forester for 3 years now and don't intend to sell it.
Edited by BreakingBad on Thursday 23 February 21:37
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