sario Posted April 4, 2011 Share Posted April 4, 2011 I'm having a little bit of trouble with the old subie again, please help! Intermittently when it's moving the whole car will jerk a little bit. It's almost like it went out of gear for a split second and then right back in... but it does the same jerk while not moving and in gear. Sometimes it will do it servele times in a row. 1997 Legacy Outback 237,000 miles Automatic original engine and transmission all fluids are full last transmission fluid change 15,000 miles ago. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 4, 2011 Share Posted April 4, 2011 any check engine lights? does the AT light flash 16 times at start up? when were the plugs and wires changed? were they NGK plugs and Subaru wires or something else? hesitation can be caused by spark plug wires. i've seen brand new out of the box aftermarket wires cause EJ engines to not even be drivable they hesitate so bad. i could easily see that being mistaken for fuel or trans issues. Quote Link to comment Share on other sites More sharing options...
sario Posted April 4, 2011 Author Share Posted April 4, 2011 any check engine lights? does the AT light flash 16 times at start up? when were the plugs and wires changed? were they NGK plugs and Subaru wires or something else? hesitation can be caused by spark plug wires. i've seen brand new out of the box aftermarket wires cause EJ engines to not even be drivable they hesitate so bad. i could easily see that being mistaken for fuel or trans issues. The plugs were changed about 6,000 miles ago, and the wires about 35,000. NGK Platnium, and OEM wires The problem hasn't happened in park or neutral, so i didn't think it was the wires, but I'll order a set today and give that a try. Quote Link to comment Share on other sites More sharing options...
sario Posted April 4, 2011 Author Share Posted April 4, 2011 oh and i forgot there are no check engine lights or transmission lights. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted April 4, 2011 Share Posted April 4, 2011 does it do this when making slow tight circles? Quote Link to comment Share on other sites More sharing options...
sario Posted April 4, 2011 Author Share Posted April 4, 2011 does it do this when making slow tight circles? Not that i have noticed. But I'll give it a try this afternoon. Quote Link to comment Share on other sites More sharing options...
sario Posted April 7, 2011 Author Share Posted April 7, 2011 (edited) I tried the turning in tight circles, no problem. I replaced the wires as Gary suggested, and found a lot of corrosion where 1&3 connect to the coil. In-fact there looks to be a little bit of damage to the coil pack from arcing. Unfortunately the wires didn't solve the problem, in fact it's worse. I'm now running really rough all the time and throwing a flashing CEL(#3 cyl misfire). I guess i need to try a new coil pack now. Thanks for your help so far John and Gary Edited April 7, 2011 by sario Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted April 7, 2011 Share Posted April 7, 2011 Unless the arcing damage is serious - I doubt you have a problem with the coil pack. If that were the case then you would also be seeing misfire's from the #4 cylinder as well. 1/2 and 3/4 share a coil - it's a "wasted spark" system..... Have you pulled the plug to check for damage or strange coloration? If that doesn't pan out..... you aren't going to like this..... run a compression check. You might be looking at a burnt exhaust valve. Has the engine received it's proper valve adjustment every 105k? Ever? You can't neglect that on the EJ25D and expect to get away with it forever - you will burn a valve sooner or later.... GD Quote Link to comment Share on other sites More sharing options...
sario Posted April 7, 2011 Author Share Posted April 7, 2011 Unless the arcing damage is serious - I doubt you have a problem with the coil pack. If that were the case then you would also be seeing misfire's from the #4 cylinder as well. 1/2 and 3/4 share a coil - it's a "wasted spark" system..... Have you pulled the plug to check for damage or strange coloration? If that doesn't pan out..... you aren't going to like this..... run a compression check. You might be looking at a burnt exhaust valve. Has the engine received it's proper valve adjustment every 105k? Ever? You can't neglect that on the EJ25D and expect to get away with it forever - you will burn a valve sooner or later.... GD You're right, i don't like the sound of that.... and I didn't pull the plug, I knew i should have, but i was trying to be quick since i have to work early tomorrow. I'll pull it tomorrow evening or Friday morning. The Valves were actually adjusted 50k ago, maybe i'll get lucky. Quote Link to comment Share on other sites More sharing options...
nipper Posted April 7, 2011 Share Posted April 7, 2011 Why are people hinting at the engine, that would be one of the last places i would look after hearing the car has been tuned up. What does the tach do when this happens? Does it go away if you manually shift the car. What happens in D3 Put the FWD fuse in a for a while and see what happens. Quote Link to comment Share on other sites More sharing options...
sario Posted April 9, 2011 Author Share Posted April 9, 2011 Thanks Nipper, I'll give that try too. But working on scubaru now has to wait until sunday. The wife talked me into a last minutes scuba trip, I didn't argue too much! Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 9, 2011 Share Posted April 9, 2011 Wait wait wait. You found corrosion on the coil pack, and damage to the post underneath the wire boot. Bad connection. Spark (electricity in general) takes the path of least resistance. If it finds that the least resistance means jumping the boot and arcing down the side of the coil that's what it's gonna do. In a wasted spark system, the two wires attached to each coil carry the spark in unison. This requires the wires and plugs to be of nearly equal resistance. If one side has higher resistance than the other, which way is the spark going to go? Replace coil pack. Quote Link to comment Share on other sites More sharing options...
sario Posted April 12, 2011 Author Share Posted April 12, 2011 Even though it tested fine, the coil pack proved to be the problem. I ended up having to use a non OEM(more expensive) one because http://www.subarugenuineparts.com/ mailed me the wrong part, but hey stuff happens. Thanks for all the help. Quote Link to comment Share on other sites More sharing options...
sario Posted April 12, 2011 Author Share Posted April 12, 2011 Wait wait wait. You found corrosion on the coil pack, and damage to the post underneath the wire boot. Bad connection. Spark (electricity in general) takes the path of least resistance. If it finds that the least resistance means jumping the boot and arcing down the side of the coil that's what it's gonna do. In a wasted spark system, the two wires attached to each coil carry the spark in unison. This requires the wires and plugs to be of nearly equal resistance. If one side has higher resistance than the other, which way is the spark going to go? Replace coil pack. Not to be contradictorily or anything Fairtax4me, i appreciate the input but after a little bit of research i found out some different information, and i'm going to post in case any searches the threads for info.. It turns out that ignition plugs are in series, the "path of least resistance" doesn't apply. Each spark plug is connected to each end of the same coil, so the current from coil actually has to travel through both ignition wires. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 12, 2011 Share Posted April 12, 2011 excellent, easy fix! THANX for the follow up and letting us know you figured it out!! i would recommend used on these since they don't fail very often and are really easy to replace and the cost is exorbitant new. if peace of mind is important to you (it is for me because i travel a lot), then just buy two used ones and stuff one in with the spare tire. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 12, 2011 Share Posted April 12, 2011 Not to be contradictorily or anything Fairtax4me, i appreciate the input but after a little bit of research i found out some different information, and i'm going to post in case any searches the threads for info.. It turns out that ignition plugs are in series, the "path of least resistance" doesn't apply. Each spark plug is connected to each end of the same coil, so the current from coil actually has to travel through both ignition wires. If I'm understanding this correctly, you did your own research rather than taking what I had to say as fact! I was just trying to keep it simple, since it takes a lot more to explain exactly how the electricity flows in the wasted spark system. Yes it can be said that the plugs are connected in series, but the path of least resistance rule always applies. The coil still discharges to the plugs. So anywhere that the spark can arc it will. Any added resistance in the plugs or wires can cause the spark to not jump the gap in the plugs. Quote Link to comment Share on other sites More sharing options...
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