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Plug swap failed to fix miss on my WRX - looking for ideas

miss WRX intermittent miss

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#26 ivans imports

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Posted 06 March 2013 - 10:05 AM

A ring land is very apparent when you look at the oil filler when reved will push smoke out and will miss at low rpms and clean up at higher rpms. a comp test will tell you while you have the plugs out two things make shure they are the right length is to different thread lengths and find some low resistance plugs ie ngk v power somtimes i see problems with platnums and iridiums being to high of resistance and the spark jumps down the side instead of down the middle.



#27 Fairtax4me

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Posted 07 March 2013 - 10:06 AM

Internal damage, valve damage ( anything mechanical basically) will be more likely to cause a steady low RPM misfire that clears up as rpms increase. If bad enough the misfire may not clear at all.

This has electrical written all over it. I'm tempted to say its an ignition coil going bad because of the intermittent nature. Maybe fuel injector, but my gut says coil.

#28 Gloyale

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Posted 07 March 2013 - 11:07 AM

the arrows on the ps uper cam indacates what #cly you are on arrow strait up addjust #1 strait right #3 strait down #2 and strait left is #4 i like them a bitt loose 0.020 mm intake and 0.025 mm exhaust factory is about 0.015 -0.020 mm the exhaust is the most important and is hard to get to i donot think it can be addjusted with cams in position. The one i did had to remove the head and grind down ends of valves to get the right clearance this was very involved and time consuming but it fixed it right up no more missfires and way smoother. for now just make shure it has enuff clearance and if it gives you a misfire code you know what cly to check first

 

.020mm would be thinner than a gnats hair.   would be .000784 in.  Thinner than any feeler gauge.

 

You mean 0.20 mm intake and .25mm exhaust.  Translates to roughly .008 in.  and .010 in. respectively.



#29 1 Lucky Texan

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Posted 07 March 2013 - 11:37 AM

Internal damage, valve damage ( anything mechanical basically) will be more likely to cause a steady low RPM misfire that clears up as rpms increase. If bad enough the misfire may not clear at all.

This has electrical written all over it. I'm tempted to say its an ignition coil going bad because of the intermittent nature. Maybe fuel injector, but my gut says coil.

 

Seriously, I perhaps have detected it once or twice at idle. Certainly no more frequent than driving at 2K rpm.

 

yesterday had to get my inspection sticker. I asked the guy if there were any pending codes, he said no.

 

haven't really done anything new yet to diagnose, perhaps after work today , certainly this weekend I will try taking the oil filler cap off and idling/reving. I also have a ground on the other side of the intake manifold to 'refresh'.

 

And I have a replacement CP sensor on the way.

 

I think I'll measure the voltage across the battery too.

 

wish I had a code, then I could swap coils and injectors....


Edited by 1 Lucky Texan, 07 March 2013 - 11:39 AM.


#30 1 Lucky Texan

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Posted 07 March 2013 - 07:24 PM

No helper to rev the engine but, is it normal for the filler tube to be pulsing? Our 03 H6 outback doesn't.(yeah, I went and fired it up in a panic if you must know)

 

Kinda freaks me out - it seems much faster than just one cylinder, like each of the 4 causes a pulse. maybe the PCV system is different for the turbo so it behaves differently than the H6?

 

I didn't see any smoke or vapor.

 

I received the Beck-Arnley CP sensor and installed it so, I will be paying VERY CLOSE attention the car for a coupla days.

 

(couldn't find my voltmeter, but I did refresh another ground though, it was all bright and shiny...)



#31 Fairtax4me

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Posted 08 March 2013 - 01:54 AM

Every EJ ive seen pulses out of the oil filler cap. Nothing to worry about there.
Have you unplugged and cleaned the connectors on the coils? What about the ignition module and bellhousing plugs?

#32 1 Lucky Texan

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Posted 08 March 2013 - 08:52 AM

pretty sure the problem is still there after this morning's drive.

still no CEL.







sigh

 


Every EJ ive seen pulses out of the oil filler cap. Nothing to worry about there.
Have you unplugged and cleaned the connectors on the coils? What about the ignition module and bellhousing plugs?

 

I may try that oil filler cap test again and have someone rev the engine, probably should observe it for several minutes anyway.

 

I did re-seat the connector on each coil when I installed the new plugs, they looked OK. Indeed, most everything on the car is still new-ish looking and grime free.

 

last night I installed the new CPS (rockauto shipped that thing fast!) and refreshed a ground on the other side of the intake mani.

 

Kinda of thinking about buying a coil and just start at cylinder one and swap it around but - I dunno.

 

Even though i asked the dealership to do a throttlebody cleaning the last time it was there, I may buy that SeaFoam spray with the curved tube and try that. (long story but, I paid them to change a bad rear wheel bearing, since it was in and they loaned me a car, I had the PCV valve replaced and asked for thottlebody cleaning. they said they did something called 'induction service' or something like that, I don't recall exactly)

 

It occurs to me also that, I have a vacuum gauge - so this weekend I will try to monitor vacuum with it.

 

i wonder if the dealer has a way to test coils and injectors?

 

 

Tell me more about the connectors and the ignition module, any diagrams or pics around?


Edited by 1 Lucky Texan, 08 March 2013 - 08:52 AM.


#33 Setright

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Posted 08 March 2013 - 09:19 AM

Dang, this is an annoying problem ! Just read the whole thread from the beginning.

 

 

If I were to place a bet on the cause, it would put my money on the exhaust valve clearance. The "chk" sound, the intermittent nature of the problem, both suggest a tight valve that is in the very early stages of breakdown. You need to find a mechanic you trust to check the clearance and give you peace of mind. Even if valve clearance is not the cause, the cost/trouble of burning and cracking a valve should be outweighed by the cost/trouble of inspection. (and repair.)

 

A local friend of mine had these EXACT symptoms with a n/a EJ20. It developed over almost 2 years, passing through a tendency to idle unevenly, lope during some accelerations...and finally running on 3 cylinders and chugging gas like I chug beer on a Friday night :D

 

Lifting the head revealed an exhaust valve that looked like it had shrunk because it had burned evenly around the entire seat perimeter. Oh, and with a big crack in it.

 

I do of course understand the slow approach, no need to rip an engine apart just for fun...

 

BEst of luck !!



#34 ivans imports

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Posted 08 March 2013 - 10:34 AM

sorry was 6 in the morning ya 0.25 0.20 mm check comp any pulsing smoke out the oil cap is bad i check most engines i work on and see very little that have any smoke out the oil filler . On the race engine i can tell just by the blowby out the oil filler if piston is broken and the comp changed from 155-100 still ran ok dident miss but blowby out the oil filler. All the cly should be within 10 psi of each other  



#35 ivans imports

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Posted 08 March 2013 - 10:40 AM

coil we have used a tin can coil mouted on the fender to check for bad coils on a 3.3 l svx had some with bad coils a loyale coil with a 2.5 d plugwire can be switched from cly to cly to test for bad coil i ran two wires to jump it the one svx ran with thiss coil for weeks while we waited for the right coil is cheap diagnostic tool



#36 1 Lucky Texan

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Posted 08 March 2013 - 11:06 AM

again - just 44.5 K miles, but, yeah, thinking having the clearances checked is coming up soon. I guess I'd like to know if there are coil and/or injector tests the dealer or a shop can do.



#37 torxxx

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Posted 08 March 2013 - 11:31 AM

not really as far as the coil goes, you could Ohm it would but other than that, I dont know of any other test.  You would show misfires on 1/2 and 3/4 the way those coils are paired together.  Only time I've seen 2/4 or 1/3 misfire was when someone dropped spark plugs and smashed the tip down to the electrode. They can noid light the injectors to make sure the pulse is occuring @ the right time, and they can remove the injector and check the spray pattern.  But you are paying them Diagnostic time, and coming from working at at shop where techs got paid by book time/commission they will ream you on the diag time. 

 

I would check your valve lash, its something you can do @ home in your driveway with a 10mm gear wrench and a set of go/stop feeling gauges.  If there is a valve out of adjustment and it is the bucket/shim style then take it to the shop and pay them to fix it.  if its the old nut/screw style (which I doubt its DOHC and turbo) fix her up your self.  Exhaust should be .018mm to .030mm  Intake .015mm - .025mm on MOST subarus.  Forced induction may be a little difference



#38 1 Lucky Texan

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Posted 08 March 2013 - 11:42 AM

bucket/shim or bucket only

 

so, even the coil on plug is wasted spark?

 

I have a message in to a 'tuner' shop several cities away. Not convenient if I have to rent a car, but, if he had to, I suppose he could monitor the car on the dyno to see what's going on.

 

I hate spending hundreds, but if i wait and a valve is compromised, it's thousands.



#39 1 Lucky Texan

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Posted 08 March 2013 - 11:46 AM

OK, if the car passed a compression test, would you still check valve lash?



#40 torxxx

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Posted 08 March 2013 - 11:53 AM

define "passed compression test"  Not tryin to talk you down, but I've had customers tell me oh I had 130 Psi on one cyl and 180 psi on the other 3.. that does not "pass"  10% within each other is generally considered spec.  
 

If you can post the numbers it'd help a bit.   

 

I wonder if Cabaroo or Calebz (I cant remember which one it is) is still around your area, IIRC hes a turbo hound, might be able to lend a hand.

 

When I say bucket/shim you can either see your valve spring or you cant.  If you cant see the valve spring with the valve covers off, its a bucket/shim lifter setup. 

 

I wouldnt really put the car on a dyno to monitor the systems, if you can find a board member that lives close to you and has a decent scanner, Live Data stream is all you really need.  Once its plugged in drive the car normally and make it act up and have someone watch the numbers.  Data stream generally shows whats going on.  Harder part is finding someone who actually knows how to fully use their scanner.  

 

Oh btw, do the dollar bill test on the tail pipe.  Just hold a dollar up to the end of the tail pipe and if it sucks the bill into the exhaust, you've got valve issues.

 

Oh yea and my bad on the coil pack info, I forget that the newer forced induction run the coil on plug setup like my SVX.  before you run out and buy a 100 dollar coil, I'd see about finding a good used one to use as a test unit.  Electrical parts generally arent returnable, so if it coil pack doing it, you'd be stuck with a spare.  

 

Sorry for being short and a little messy with my explanations..  Its early and I have not partaken in my safety meeting yet


Edited by torxxx, 08 March 2013 - 12:01 PM.


#41 1 Lucky Texan

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Posted 08 March 2013 - 12:22 PM

well, I'm at work and am usually short, often posting while parts program.

 

sorry for the confusion - no comp test yet. Just wondering IF the numbers were close, you'd STILL check valve lash.

 

supposedly the 06 WRX does have buckets, not sure if the STI only has the selectable bucket sizes or if the WRX has shims as well. def. not screw-with-locknut though. evidently, the device to adjust in car is $300.



#42 torxxx

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Posted 08 March 2013 - 12:29 PM

you dont "need" the device.  There is always a way around Subaru tools.  The idea behind their tool is to hold the cams in place while you do the test.  You can always get a motor turned over to where each cylinder has closed valves.  You can test the intake valves with the exhaust valves open.  I've never bothered with Subarus 900 page guide on checking valve clearances.  Simply look at the cam lob, make sure that the cam lobe isnt putting any pressure on the shim/bucket/spring etc.  slide the feeler gauge in and see what #'s you get.

 

If you came up with 180 all the way across the board, with the engine cold and warm, and it passed the dollar bill on the exhaust test I myself would say the valve clearance was probably ok.  

 

04-06 was a bad year for subaru testing Active valve timing, does your motor have that on it?  Just brought up a thought about a motor a customer gave me for free because he swore it had a bad valve, came down to one of the actuator arms for the active valve timing had cracked, and it wasn't opening the second intake valve correctly and causing a misfire



#43 1 Lucky Texan

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Posted 08 March 2013 - 01:35 PM

you dont "need" the device.  There is always a way around Subaru tools.  The idea behind their tool is to hold the cams in place while you do the test.  You can always get a motor turned over to where each cylinder has closed valves.  You can test the intake valves with the exhaust valves open.  I've never bothered with Subarus 900 page guide on checking valve clearances.  Simply look at the cam lob, make sure that the cam lobe isnt putting any pressure on the shim/bucket/spring etc.  slide the feeler gauge in and see what #'s you get.

 

If you came up with 180 all the way across the board, with the engine cold and warm, and it passed the dollar bill on the exhaust test I myself would say the valve clearance was probably ok.  

 

04-06 was a bad year for subaru testing Active valve timing, does your motor have that on it?  Just brought up a thought about a motor a customer gave me for free because he swore it had a bad valve, came down to one of the actuator arms for the active valve timing had cracked, and it wasn't opening the second intake valve correctly and causing a misfire

 

 

yep - active valve lift/timing w'ever.

 

dunno what rpm that starts kicking in though. I've had misses at every RPM below 3K. not too sure above that as noise and torque/power start taking over.


Edited by 1 Lucky Texan, 08 March 2013 - 01:36 PM.


#44 Setright

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Posted 09 March 2013 - 05:00 AM

Passing a compression test, would be a good sign...but your problem is intermittent, and you could not be 100% certain that one of the valves isn't too tight.

 

 

AVCS...doesn't the WRX have "tumbler valves" in the intake too? I suppose a small defect in one of these systems could cause your symptoms.

 

The low mileage doesn't really exclude a mechanical problem :-(



#45 1 Lucky Texan

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Posted 09 March 2013 - 10:12 AM

yep, TGV is present too. And, due to being above the injectors, could only be cleaned with 'induction service' or some other solvent introduced thru the throttlebody.  If I hadn't paid a dealership to do that a few months ago, I'd try the SeaFoam Spray kit on it. (If I had more time and money, I'd do a TGV delete mod.)

 

Tried cleaning the MAF last night, took a little drive this morning to bring back some breakfast goodies. Still missing.

 

beginning to rain but, I may swap pl;aces with the wife's car in the garage and hook up the vacuum gauge.

 

quickly running out of stuff I can try myself. I DO have RomRaider on my laptop and a tactrix cable. I just need to educate myself on how to log with it while driving - but, since I have no MIL or even pending codes, I don't see how logging OBDII data would detect anything.


Edited by 1 Lucky Texan, 09 March 2013 - 10:13 AM.


#46 ivans imports

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Posted 09 March 2013 - 10:23 AM

the wrx heads are a pain to addjust the valves cam has to be pulled and buckets replaced i did it by removing the heads and grinding the tip of the valve till i got the right clearance took me 12 hours to addjust the valves on all four holes and both heads had to be removed but spent 0$ on buckets and was bang on. and i had the head on the bench way easyer to work with. whould realy like to see the comp test #ers



#47 Gloyale

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Posted 09 March 2013 - 12:01 PM

 
beginning to rain but, I may swap pl;aces with the wife's car in the garage and hook up the vacuum gauge.
 
quickly running out of stuff I can try myself. I DO have RomRaider on my laptop and a tactrix cable. I just need to educate myself on how to log with it while driving - but, since I have no MIL or even pending codes, I don't see how logging OBDII data would detect anything.


A vacuum gauge will tell you a lot. If it jumps by 5 or more at idle you got a bad valve.

Leak down test will confirm. Compression not so much could make good compression and still be leaking.

Vac test and if it's jumpy do a leakdown.

#48 1 Lucky Texan

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Posted 12 March 2013 - 08:00 AM

still need to get the vac gauge on it. maybe after work since we have more light now.

 

last night , for the first time, I tried the logger part of RomRaider.
Evidently, I can't determine which USB port is mapped to com3 on my lenovo laptop. Windows 7
control panel not as helpful as versions in the 'old days'.



interesting thing is, for about a day and ahlf, I haven't felt it miss.
If it did it, it was too subtle. But, it has done this before. I doubt I
would feel convinced the problem was fixed unless it was free of
symptoms for a week or more. I suppose cleaning the MAF 'could' have
been helpful and it took a coupla drive cycles to re-learn? still, too
soon to be feel convinced.


Edited by 1 Lucky Texan, 12 March 2013 - 08:01 AM.


#49 Setright

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Posted 12 March 2013 - 09:31 AM

Fingers crossed :-)



#50 1 Lucky Texan

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Posted 14 March 2013 - 09:07 AM

still fails

 

Trying to get over the learning curve with RomRaider. I have it reading realtime, but my first attempt at logging , the file got 'lost'/unrecorded.

 

the weird thing, I selected misfire count for all 4 cylinders. only recorded 2 misfires in 20 minutes of driving.

 

different cylinders, at idle, while warming up, before I left the driveway!


Edited by 1 Lucky Texan, 14 March 2013 - 09:12 AM.






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