Just another misfire/rough idle thread...

[heiche]

You sure that's a stain? What if it's a metallic deposit? If so, wouldn't it could cause the #2 plug to "misfire"?

 

Can you test resistance across the spot, from one end to the other?

[xt2005bonbon]

Up close and in-person, plugs 1, 3, and 4 look almost identical to each other.

 

Really? I mean plug 1 is clearly darker than the others. But it does not really matter if you did not get any roughness from that cylinder.

[StkmltS]

My miss is not being caused by the plugs, coil packs, or injectors.

There may be a problem with the connectors or the wiring, but the devices themselves are not the root cause.

 

Until recently I was careful to only make one change at a time, so that if the miss changed I'd know exactly why.

My spirit has been broken, and now I'm totally satisfied just by blindly trying handfuls of fixes at the same time and praying for a change... any change.

 

Here's an short(ened) list of things that haven't caused a measurable change:

Original intake manifold o-ring gaskets

New intake manifold o-ring gaskets

Old spark plugs

Old spark plugs re-gapped

Old spark plugs w/ swapped positions

New spark plugs

New spark plugs w/swapped positions

Original coil packs

Original coil packs w/ swapped positions

New coil packs

Original injectors

Original injectors w/ new o-rings

Original injectors ultrasonic cleaned

Original injectors w/ swapped positions

New (used) injector in cyl 2

New silicone vacuum hose

Original TGV gaskets

New TGV gaskets

Rebuilt motor

FPR ref line relocated to the BPV

Edited June 13, 2017 by StkmltS

[heiche]

Gotcha. Just a strange spot on that plug, like on Jupiter.

[xt2005bonbon]

So, now you need to figure out the root cause of the oil/fuel pool you found in cylinder 2.

[SBT]

Sounds directly connected to fuel... and more injector related. You're getting excess fuel in Nr 2. Are these new injectors? How does injector timing look in your tables? AFRs? Seems on the surface that you are too rich in that cylinder.

[StkmltS]

Sounds directly connected to fuel... and more injector related. You're getting excess fuel in Nr 2. Are these new injectors? How does injector timing look in your tables? AFRs? Seems on the surface that you are too rich in that cylinder.

The problem started when all four injectors were still OEM that came with the car. After I bought one used injector on ebay the problem continued.

 

I was still on the 100% stock tune when the problem started, so I doubt the problem is in the tune. Which injector tables are you referring to?

 

My AFR (per LVs) are almost always well within the ±5% that people say is acceptable. As of a couple days ago they were -2.60/0.60/4.60/-0.80.

 

In the past, increasing the fuel (lower target AFR) actually reduced the quantity and frequency of misses. So far that's the only thing I've been able to do that's affected the misfiring. I posted a few charts many pages back... somewhere.

 

Why do you say I'm getting excess fuel in #2?

I'm inclined to think that I'm getting not enough fuel (low fuel pressure, leaky housing, AFR slightly too lean, observed MPG consistently 1-2 mpg better than the displayed MPG).

Edited June 30, 2017 by StkmltS

[StkmltS]

USPS says my new (used) fuel pump and housing are waiting for me at home. I'll swap it in later tonight if I have time after the kids are in bed.

 

*Update* Didn't happen last night. I didn't buy what I thought I bought so I'm back to fixing my housing and putting in a new (used) pump.

Edited June 30, 2017 by StkmltS

[StkmltS]

So a new fuel pump and filter didn't stop the misfiring.

My cracked housing is a problem, but it's cracked in an area that I don't think affects fuel pressure (see pics).

I fixed the crack with some super-super-glue + powdered plastic, but long-term my housing will need replaced.

 

Pics aren't uploading from my work computer so I'll try to upload them later.

[xt2005bonbon]

Man, will you EVER get this thing fixed? This must be so frustrating.

 

Can't remember. Did you ever rechecked the valve clearance since the rebuild?

 

Or redid a leakdown test and or compression test?

[FSuperDuty]

Jumping into this thread - my wife's XT has been giving me fits since February of this year (2017).

 

@StkmltS - thanks for documenting your journey so well! I thought I was going to have less issues when I jumped off the Audi bandwagon but our XT has me going in circles...

[xt2005bonbon]

^What is up with your car?

[FSuperDuty]

^What is up with your car?

 

Don't want to hijack from the OP, but this thread covers most of where I've been. Short answer, Cyl #2 misfire that hasn't responded to the typical troubleshooting list.

 

http://www.subaruoutback.org/forums/66-problems-maintenance/410874-any-romraider-tips-2006-obxt-p0302-p0304-rough-idle.html

 

I landed here searching for more answers and it seems that i've done most of what the OP has tried. Currently sending more logs to a tuner guy for advice, but so far all we can confirm is a lean condition at idle. It looks like an intake leak from the numbers but nothing shows up with all the smoke testing I've done...

 

Meanwhile the idle is just getting worse, still confined to #2 misfire, and the fuel economy has dropped 2-3 mpg since Feb of this year. But still pulls like snot at WOT.

 

Maybe the solution is a very tall cliff, if not for how much my wife likes the car.

[xt2005bonbon]

Ah, OP won't mind

 

Have you checked your valve clearances?

[Outback2.5XT-05]

It looks like an intake leak from the numbers but nothing shows up with all the smoke testing I've done...

 

Just popping in here and sorry if it's already been discussed but my understanding is that a boost leak/intake pressure test is more telling than smoke in some cases, might this be one?

[FSuperDuty]

Ah, OP won't mind

 

Have you checked your valve clearances?

 

Not yet. I've gotten to the end of my abilities / available time and looking for a good shop to do it along with a leakdown. Hate to go to the stealership!

 

Just popping in here and sorry if it's already been discussed but my understanding is that a boost leak/intake pressure test is more telling than smoke in some cases, might this be one?

 

I am still questioning if I've done my testing correctly, still hadn't found a definitive description on how to setup the test for our XT. Read more on how to setup a WRX but they're not exactly the same (and even those accounts are conflicting).

 

What I did was block off the intake just after the MAF with a PVC cap, then I think I fed smoke into the intake @ about 5psi through the BOV vacuum line, using an eBay paint can smoke tester. (That thing makes a ton of smoke!)

 

Don't completely remember the process, but it was enough pressure to reveal my TMIC to TB boot was leaking (which I replaced with a COBB version). Didn't improve the misfires but the car made more boost at least.

 

Still, I didn't block off any other lines (maybe I should have) but every time I try to decipher a vacuum line diagram of what I should block off I just get lost...

[xt2005bonbon]

It really is not that hard to check the valve clearance yourself. You should seriously look into it.

 

 

1.remove battery

2. remove coil packs

3. remove spark plugs

4. remove valve cover

5. check clearance.

 

This will cost you your time, a new valve cover gasket, and some permatex.

 

I would do this if you know that you've check for vacuum/boost leaks, have ruled out spark plugs/injector/coil packs.

Edited November 15, 2017 by xt2005bonbon

[StkmltS]

Man, will you EVER get this thing fixed? This must be so frustrating.

 

Can't remember. Did you ever rechecked the valve clearance since the rebuild?

 

Or redid a leakdown test and or compression test?

 

I haven't done anything to it since I replaced the fuel pump, and since then (June 30) I've only put on about 2k miles. It's easier not worrying about the car when I'm not driving it... how messed up is that. Most (all) of my free time lately has been spent helping my friend rebuild the motor from his '08 LGT. His turbo destroyed itself and sent an impressive amount of lapping compound (metal) through the entire engine. He opted to take the YNANSB route and it took us about 3 months of one or two nights a week. We finally got it running last week, and on his first day driving home from work the radiator broke (?). Such is life.

 

Jumping into this thread - my wife's XT has been giving me fits since February of this year (2017).

 

@StkmltS - thanks for documenting your journey so well! I thought I was going to have less issues when I jumped off the Audi bandwagon but our XT has me going in circles...

My pleasure, it's been very helpful for me also just being able to go back and look at what I've tried. Going on three years now would be a long time to keep things strait if I was going off just memory.

 

I love it when people jump into this thread with their own symptoms because it helps me think through my own stuff from a different perspective. So all hijackers are welcome here

 

...

What I did was block off the intake just after the MAF with a PVC cap, then I think I fed smoke into the intake @ about 5psi through the BOV vacuum line, using an eBay paint can smoke tester. (That thing makes a ton of smoke!)

 

Don't completely remember the process, but it was enough pressure to reveal my TMIC to TB boot was leaking (which I replaced with a COBB version). Didn't improve the misfires but the car made more boost at least.

 

Still, I didn't block off any other lines (maybe I should have) but every time I try to decipher a vacuum line diagram of what I should block off I just get lost...

I don't think you block off any lines because then you wouldn't be testing the entire system (everywhere air can go). ALL new air is supposed to enter the engine only through the intake tube. You plugged that tube with a PVC cap, so you did it correctly.

 

Can you post a link for the smoker you used? I really struggled to keep my DIY can smoking and I'd like to do it again using something that works better.

Edited November 15, 2017 by StkmltS

[StkmltS]

Recently I met a mechanic who dealt with a Misfiring Subaru, with symptoms similar to mine. They (a private shop) couldn't figure it out and ended up replacing the motor, which didn't fix the problem. Long story short → the misfire stopped after the ECU was replaced.

 

I'm contemplating that as my next move. If it didn't require a trip to the dealer I'd probably have replaced it already. Is it something I can swap out myself in the dealership's parking lot? I still need to take it in for the airbag recall so maybe they'd charge me less if the car was already in for something else.

[xt2005bonbon]

I would think you can swap it yourself. Shouldn't be a big deal. heiche, if you're here, you agree?

[StkmltS]

I'm under the impression that the BIU / immobilizer doesn't play nice with a replaced ECU until the dealer talks magic and makes everything cooperate.

[xt2005bonbon]

I would have thought they'd be independent from each other. But maybe not.

[birkhoff]

. . . I still need to take it in for the airbag recall so maybe they'd charge me less if the car was already in for something else.

 

Don't count on it.

 

Tried it. Got shut down.

[StkmltS]

I would have thought they'd be independent from each other. But maybe not.

I'll have to look into it deeper. I'd love to be wrong and be able to do it all myself.

 

Hold on... I just had a happy moment dreaming about what it would be like to own an LGT that didn't misfire.

 

Don't count on it.

 

Tried it. Got shut down.

Hopefully they'll at least be willing to toss in my new cabin filter.

Edited November 16, 2017 by StkmltS

[FSuperDuty]

It really is not that hard to check the valve clearance yourself. You should seriously look into it.

 

Definitely. I'm calling another local shop today that I've heard good things about. As it stands, my wife is running out of patience and between a FT job and side biz I can only work on her car on weekends... *cry me a river* so I'm hoping they can fast forward my to-do list for me...

 

 

Can you post a link for the smoker you used? I really struggled to keep my DIY can smoking and I'd like to do it again using something that works better.

 

Here ya go ... I had to open it up and cover the wick with a larger rag b/c I burnt up part of it, but otherwise has been super useful. Just don't run it too long or it will get crazy hot!

 

https://www.ebay.com/itm/EVAP-Smoke-Machine-Diagnostic-Emissions-Vacuum-Leak-tester-BRAND-NEW/281805683189?hash=item419ced79f5:g:7rgAAOSw8TBZcFX-:sc:USPSPriority!29680!US!-1

 

Recently I met a mechanic who dealt with a Misfiring Subaru, with symptoms similar to mine. They (a private shop) couldn't figure it out and ended up replacing the motor, which didn't fix the problem. Long story short → the misfire stopped after the ECU was replaced.

 

 

Wow. I've read a ton of threads but can't say I've heard that one yet.

 

I wonder if replacing the ECU worked because the ECU was truly bad or because the programming was different? Reason I ask is that that I've been getting help from this guy interpreting the logs and he mentioned making some adjustments after we rule out mechanical:

 

http://xtremeracingtuning.com/