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Extremely Frustrated - Misfires!

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45K views 19 replies 13 participants last post by  rabbitnutz  
#1 · (Edited)
YouTube - Subaru 2 & 4 Misfire Issue

I'm so freaking frustrated right now, it's not even funny...

Took the car to the shop after misfire on 2 & 4 that started out of nowhere a couple of weeks ago, they said to replace the plugs and coil packs on that side. I had a feeling they're just saying that because that's the most obvious, but I was hesitant because I just had a feeling it was something else, NOT the coil packs.....

So, replaced the coil packs on 2 & 4 and new iridium plugs for all 4 cylinders, still have misfire on 2 & 4 (but no CEL codes at all since the shop). Drove it around the block, STILL no CEL code, still misfiring. Let it idle in the garage for a couple minutes, STILL misfiring and the computer still refuses to throw up a CEL.

So I unplugged the two coil packs on cylinder 1 & 3 and the car didn't start. So I unplugged them on 2 & 4 and the car ran exactly as it did when the problem first happened misfiring on 2 & 4 (but still no CEL).

And if I unplug either coil pack on 2 & 4 (running it on essentially 3 cylinders) it doesn't matter, runs the same as if 2 & 4 were never plugged in.

NOW HERE IS THE STRANGE PART!

I hear a strange mechanical "clunking around" noise when I first start it up when it's cold. It's like the car starts up normal (firing on all 4 cylinders perfectly fine), then the clunking sound happens within a half-second of starting it, then it IMMEDIATELY starts to misfire. It happens really fast (within a second to a second and a half of starting it).

----BUT----

It will NOT do the clunking noise again until the engine cools back down (being off for 20 minutes or more). You can start it all you want after the first clunking noise, and it won't do it ever again until you shut it off and let it sit. :confused:

So, really! is going on? Anyone have any ideas, or sound like ANYTHING? I've dropped engines and transmissions, and always worked on my cars, but this is something that completely baffles me, and I would like to have some sort of idea of what I'm talking about if I end up trailering it to the dealer (70 miles away).

I'll take a video of the car making the clunking noise later tonight (once it has time to cool down) and I'll post it up so you guys know exactly what I'm on about.
 
#4 ·
^^ Resetting it by unplugging it for 30 minutes to overnight? I've been doing that all week, with no success. Battery was out of the car for a couple days while I waited for parts too.

Is there another surefire way to reset it?
 
#6 ·
Pull the coil packs and plugs and check to see if you get a spark when cranking. You will need a friend and I would suggest disconnecting the fuel injectors to reduce the chance of fouling. Always a good idea to check compresssion. I had a similar issue with my old 02 wrx. The first time it as clogged injector. The second time it was the conectors on the coil packs. As or the clacking noise. If I had to guess I would say a worn out hydraulic lifter.When the engine sits oil will leak out of the lifter. When the engine is fired backup you get the clack until the lifter fills back up with oil.
 
#7 ·
Anyone else have any clue? I may be towing it to the dealer tomorrow (even though I HATE the dealer I'm going to). But the only one other than that is 300 miles away......and that tow bill would be crazy. :crazy:
 
#10 ·
If you lack the ability to perform any of the above mentioned checks...call the tow truck. No one is going to have the magic answer here, you are going to have to perform some diagnostics or pay someone to do it for you. The dealer will probably do the following: Scan the ECM for codes, Check for spark, Check for fuel and Check compression. Unless they are complete idiots as many dealer techs are (no offense to the good ones, you are few and far between). If the latter is true (hopefully not) they will probably try to sell you a host of parts that their scan tool points to. Good luck.
 
#11 ·
^^ Just checking to see if anyone had any similar issues and what they did to resolve them (sometimes it's a fix that you would have never thought of until someone mentions it). But I appreciate the input and will be mentioning to check all that stuff when I take it to the dealer........(just saying that word makes my credit card shiver with fear.)

Hopefully the dealer close to me will check all that stuff, but I doubt it. They'll probably do the same thing the other shop I took it to did........"it says misfire on 2 & 4, so replace the coils and plugs", so I'm going to have to stick around while they check it and watch them do so. It'll be a long day. :icon_frown:

Wish me luck, borrowed a friends truck and a trailer, so we'll see what comes of this.
 
#13 ·
if you want something simple to try. with the engine running reach down and press the coil pack connector firmly into the coil pack and see if there is any change. The attaching clips on the coil pack connectors of my 02 wrx had worn out. After removing them to do a timing belt job they would not hold tightly to the coil pack anymore. Normal engine vibrations was all it took for them to back off enough to cause a misfire.
 
#14 · (Edited by Moderator)
I know this is an old video but I want to post what the causes all of these symptoms. There is a service bulletin that many of you are probably aware of that talks about removing the oil screens that are located in banjo bolts
on the heads. Here is a link to forced performance that has the Subaru documents explaining the problems these cause

http://store.forcedperformance.net/merchant2/merchant.mvc?Screen=Info_SubaruOil

Had to put some spaces in the address so it would post, sorry.

All the articles are talking about turbo failure and the screens getting clogged. But what I have not seen anyone talk about is these filters coming apart. Well mine did and caused this exact and I mean exact same problem. We ran compression checks and all sorts of other tests everything came back fine. We put new injectors in but still the same problem. We finally hooked up a vacuum gauge to port vacuum and the needle was all bouncing all over (a definite sing that there is valve trouble) So on a whim we took out the filter on the left side and it was all mangled up. Removed filter and all the debris or so i thought. A piece of that screen found its way into the oil control valve that kept it stuck wide open. The oil control valves on the 2.5 DOHC engines controls the variable valve timing. So with it stuck in the open position it was throwing of the timing off at idle. We remove the one 10mm bolt holding the valve in (located on the top front of both heads) removed the piece of the screen and made sure valve was working and walla it went from running exactly like this vehicle (Start up noise and everything) to running better that it ever has.
 
#15 ·
im also aware of the avcs sensors failing, although it may only apply to jdm wrx's. the sensors fail, fill up with oil, then the oil tracks its way up the loom, ultimately into the ecu... had a mates car do it recently over here.

caused all kinds of miss fires, random CEL's etc.
car ran like crap. dont know how the dealers fixed the loom, but he has new sensors.
 
#17 ·
The clunking when stated sounds like fluid in the cyl if its a deep knock. Maybe a leaking injector or HG. Typically The ecu driver transistor has to GND to fire the injector - dont know how subaru does this = they could be fubar. Mechanically the Valves are not clearanced too tight, yes?
 
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#19 ·
Yes, I found the reason for this problem. The issue is simply that I had a compression leak. (though the dealer didn't tell me where it was leaking from). Didn't know if it was valves or the rings. So I ended up replacing the entire engine............you can read through my "4 Month Nightmare" thread for details on all that.
 
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