mpudz Posted July 29, 2011 Share Posted July 29, 2011 (edited) Hey guys... I'm new to the forum and hoping to get some help with some misfiring issues that have gotten pretty bad lately. Here's the run down: - The car is a 1997 Legacy GT (157k miles) with a few mods (relevant ones being an intake with K&N filter and a header back Stromung exhaust) - Misfires started about 4 years ago, and the CEL would come on a few times a year and it would be random cylinders (sometimes 1, sometimes a pair of cylinders at the same time) - For about the past year, I've noticed that 95% of the time, the CEL comes on while cruising on the highway (5th gear, about 3000-3500rpm) - Within the past few months, when the CEL comes on while cruising on the highway, it is not steady, but flashing... but I don't feel a change in performance. However, at that speed, running on 3 cylinders vs. 4 might not be noticeable. - When I scan for codes, lately it's been either misfire on cyl 1&2 OR misfire on cyl 3&4, so they seem to be occurring in pairs. - Finally, a few days ago I was sitting in the parking lot and noticed that if I give it just a bit of throttle (1000-1500rpm), the car shakes, which is definitely a result of misfires. And of course, the CEL comes on when that happens. The car does not misfire while idling... idle is very smooth. - I'm running NGK copper plugs (just changed about 2k miles ago) and NGK wires. I've got a coil pack on the way just in case that's the problem. That about sums it up... I wasnt too concered about a few misfires per year, but with the CEL flashing often lately, I'm scared to destroy my Stromung cat :/ Oh, and I don't know if the dollar bill test is worth anything, but I did that and get no negative air flow... the bill flutters slightly but it's always positive flow. Any help is greatly appreciated... Edited July 29, 2011 by mpudz Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted July 29, 2011 Share Posted July 29, 2011 Have the plug wires ever been changed? If not you need to do that first - if they have you should make sure they are OEM or NGK wires. Other brands have a history of not working well for members of this forum. Your engine calls for double platinum plugs. This is due to the innaccesibility of the plugs. NGK or Denso double plat's work well. I would swap out to those. Coil pack is a good sugestion - have you Ohm'd out your coil pack to see if it's showing it's age? Another possibility is a failing ignitor - it's in the center of the firewall - straight back. Has a 5 pin connector IIRC. You can try a used one. Run a compression check? I've seen strange things happen including loose cam sprocket bolts causing damage to the cam nose and advancing the intake valve timing..... compression should be no more than 185 to 190 and not significantly less than 150 but depends on your gauge, altitude, etc. A properly calibrated test at close to sea level on a good engine will be about 185 psi. GD Quote Link to comment Share on other sites More sharing options...
mpudz Posted July 29, 2011 Author Share Posted July 29, 2011 Thanks for the suggestions. I have new NGK wires that I'll be changing soon, but I'm fairly sure that isn't the problem as this misfiring issue existed before the last time I changed my wires (current ones are also NGKs). I did check out my coil pack and it says the primary resistance is 1.3-1.4 (should be about 0.6-0.8) ... but I have a cheap multimeter so it's probably just an inaccurate reading. The secondary resistance is within spec. I have not checked out the ignitor yet so I'll try finding a used one if the new coil doesn't solve the issue (is the ignitor easy to replace?) Good suggestion on the compression check... I'll do that when I change the wires in a few days (can I remove the plugs and put them back in, or does doing that damage the plug seals?) I'm just hoping it's not the valves... I hear this engine should have a valve adjustment around 100k miles and I'm currently at 157k :-\ Quote Link to comment Share on other sites More sharing options...
bstone Posted July 29, 2011 Share Posted July 29, 2011 Put the right plugs in and you might solve the issue. Get the gap right. Check for vacuum leaks, also. If you can run a smoke test. I did the other day and was amazed with what I found. Quote Link to comment Share on other sites More sharing options...
mpudz Posted July 29, 2011 Author Share Posted July 29, 2011 Thanks bstone. I've been running NGK V Coppers on this car since the first plug change I did, so I think the plugs work well with the car - and I was very careful to ensure a proper gap. But when I do the compression test, I'll make sure they look ok. I wish I could run a smoke test, but don't have the tools. I'm seriously thinking of taking it to a mechanic pretty soon... really concerned about destroying the catalytic converter. Do you guys think it could be an O2 sensor? If so, which one is more important to change? (I'm guessing the first one, pre-cat?) Quote Link to comment Share on other sites More sharing options...
idosubaru Posted July 29, 2011 Share Posted July 29, 2011 (edited) have you changed the plugs/wires/coil pack as you've hinted at previously? i would definitely get another coil pack on there and see what happens. i doubt it's the O2 sensor but it would be the first if any. i had a tough misfire last year that would not respond to plugs, wires, coil pack, or igniter changes. swapped the entire intake manifold because i had another and it solved it. i assume it was fuel supply related since injectors can cause it too. as you've suggested a valve adjustment is a really good idea. Edited July 29, 2011 by grossgary Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted July 30, 2011 Share Posted July 30, 2011 i don't think the NGK V coppers are stock spec for this car. if you are going to change out the ones in your car, put in the stock spec NGK plugs. they only cost about $2 each and they work great. the better ones you are running may be fine, but they are not stock. and if they are causing a problem the stock plugs will cure it. keep it simple. Quote Link to comment Share on other sites More sharing options...
Olnick Posted July 30, 2011 Share Posted July 30, 2011 If I remember correctly the NGK "V" coppers are the basic $2 plugs. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted July 30, 2011 Share Posted July 30, 2011 if so, my mistake. i just don't remember hearing them referred to that way. Quote Link to comment Share on other sites More sharing options...
mpudz Posted July 30, 2011 Author Share Posted July 30, 2011 there are NGK plugs that are more basic than the V Coppers that fit the Legacy's, but the stock plugs according to my manual for my car are actually the NGK platinum plugs (which are like $12 a pop) Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted July 30, 2011 Share Posted July 30, 2011 from the 98 owners manual. Spark plugs 2.2 Liter models RC10YC4 (Champion) [Alternate] BKR6E-11 (NGK), K20PR-U11 (NIPPON DENSO) 2.5 Liter models PFR5B-11 (NGK) Spark plug gap 0.039 to 0.043 in. (1.0 to 1.1 mm) Quote Link to comment Share on other sites More sharing options...
mpudz Posted July 30, 2011 Author Share Posted July 30, 2011 Yup that's right. I am convinced it's not the plugs though since the problem didn't exist with these plugs at one point. I will update after changing the coil this coming week... but I'm doubting it's the coil. Is it normal for a coil to fail only at certain RPMs... and wouldn't it be a more consistent issue (as in, happening all the time?) Is this characteristic of how an ignition coil fails? I just ran the code for the latest CEL and it's only a misfire on cyl 1 this time... Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted July 30, 2011 Share Posted July 30, 2011 well it turns out that i have been reading too many online forums and believing them. it appears that the stock plug for the ej25d is not a $2.00 plug but a $10.00 plug. according to the site below, the stock plug is a ''premium'' class plug. and the $2 plug is a regular class plug. there are also several in between. http://www.ngk.com/results_app.asp?aaia=1305548 Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted July 30, 2011 Share Posted July 30, 2011 The stock plug for the DOHC engines is always a double platinum - not because a cheaper plug won't work fine - but rather because it's such a huge pain to get to them. The NGK double plat's are about $10 to $12 each.... I get the Denso double plat's for about $6 each and they works just as well in my experience. Though on turbo's I typically will run Iridium's for the longer life. GD Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted August 2, 2011 Share Posted August 2, 2011 in my 97 FSM they go as far to say what section of your spark plug socket plus the U joint what size length it should be for easy effort to get the plugs out Quote Link to comment Share on other sites More sharing options...
mpudz Posted August 30, 2011 Author Share Posted August 30, 2011 So an interesting update on my misfiring issue... I got a new coil pack 2 weeks ago and put it in with no problem. I drove the car and everything felt great... I was 2 weeks in with no CEL at all. I was 100% sure the problem was fixed as I used to get misfires at least every other day with the old coil pack. And then today came around... I was cruising on the highway at around 70mph and lo and behold, the flashing CEL was back in a fury. I ran the codes when I got home and had misfires on all 4 cylinders... something that had never happened before. It used to always be cyl. 1 and 2, or 3 and 4 or some other combination, but never all 4... So now I'm completely lost. The problem is so inconsistent I don't know where to look next for the issue. As always, any ideas are greatly appreciated... thanks. Quote Link to comment Share on other sites More sharing options...
bstone Posted August 30, 2011 Share Posted August 30, 2011 Sounds like you're burning out coil packs. Use the search function and try to find the thread from a few months ago about someone with the same issue. I forgot how he solved it. Maybe a grounding issue. Quote Link to comment Share on other sites More sharing options...
mpudz Posted September 4, 2011 Author Share Posted September 4, 2011 Could be... it's so hard to diagnose. What are the odds it's the crankshaft position sensor? Quote Link to comment Share on other sites More sharing options...
crws Posted October 19, 2011 Share Posted October 19, 2011 Any updates from the OP? Quote Link to comment Share on other sites More sharing options...
jcsvx Posted January 21, 2012 Share Posted January 21, 2012 OK we have fixed this problem on three different 2.5s in the last year all three have had loose front balancers the bolts were tight but bottomed out in crank the key-way and key were worn and had to replace key on all three and new washer and shorten bolt one thread (grinder) the loose balancer causes noise and the knock sensor retards the timing until it missfires and turns on cel. Hope this fix works for you too Joe Quote Link to comment Share on other sites More sharing options...
mpudz Posted January 22, 2012 Author Share Posted January 22, 2012 Thanks for the reply Joe! I still have not figured this issue out yet, but this is an interesting theory. The balancer you're talking about is the harmonic balancer AKA the crank pulley, correct? I will pull it off and see if the key-way and key are worn as you mentioned. I have had an underdrive crank pulley on my car for the past 8 years or so, and the problem started years after putting it on... perhaps that is part of the problem. Would it make sense for the car to only misfire while cruising on the highway thought? Is it that particular frequency that makes the knock sensor retard the timing? Thanks Joe... I've had 2 mechanics and 3 friends who claim to be "mechanics" look at this problem and none of them had an answer! Quote Link to comment Share on other sites More sharing options...
jcsvx Posted January 22, 2012 Share Posted January 22, 2012 my guess is at steady speeds or idle is when the pully can move, under load such as accelerating there would be enough resitance to hold it in one position. only the really bad one that was loose enough to feel by hand, (and it set the cel every few minutes) would act up almost constantly. Quote Link to comment Share on other sites More sharing options...
fixingrusinc83 Posted January 22, 2012 Share Posted January 22, 2012 Lets see it is a 5sp so When the nuetral safety switch goes bad the car goes into limp mode over 3500 RPM and will set a misfire The switch will look good but is 1/4 inch shorter when bad. Quote Link to comment Share on other sites More sharing options...
ccrinc Posted January 22, 2012 Share Posted January 22, 2012 This is such a common problem. Thanks to a mutual colleague who's on this forum, we found out it's probably in need of a valve adjust. I had a '97 Outback Limited with that issue and found out about "the cure" just after I sold it. Quote Link to comment Share on other sites More sharing options...
davebugs Posted January 22, 2012 Share Posted January 22, 2012 This is such a common problem. Thanks to a mutual colleague who's on this forum, we found out it's probably in need of a valve adjust. I had a '97 Outback Limited with that issue and found out about "the cure" just after I sold it. I have had this also be a problem at higher RPM's on a 97 Outback as well. With the shims to adjust the valves. And same thing I sold it that way. Happened after car was warm. Quote Link to comment Share on other sites More sharing options...
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