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Just another misfire/rough idle thread...


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I hate tracking these things down.

My wife is starting to ask if my car is going to ever be running right...

I need to get this resolved :lol:

 

I know the feeling :spin:

 

The correct way to handle this situation is to only talk to your wife about your car issues if and when she asks. Be honest with her and don't lie, but be careful to only give her direct answers that give her confidence in your ability to address these regular maintenance issues that come with turbo Subarus. The single worst phrase I've learned to avoid at all costs is "I think this should be the last thing for a while".

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The correct way to handle this situation is to only talk to your wife about your car issues if and when she asks. Be honest with her and don't lie, but be careful to only give her direct answers that give her confidence in your ability to address these regular maintenance issues that come with turbo Subarus. The single worst phrase I've learned to avoid at all costs is "I think this should be the last thing for a while".

 

:lol:

 

I've been at this stage for over a year now...

She knows I like working on it, most of the time it's because I want to.

It's my therapy from a really stressful job.

I don't bring it up, she'll ask from time to time.

When I'm troubleshooting, I can't get it out of my mind.

So I'm out there a lot tinkering when something is wrong.

 

Like right now, I should be working, but I want to go reflash my tune.

I'm now on the theory that my tune was done with a small leak.

And my MAF scaling is actually off, not that I'm leaking any more

So I'm going to adjust that and see what happens.

 

Interesting... my tune had the MAF values scaled up 14% for the idle voltage range.

And my ECU is adjusting down ~14%...

I'm going to return the MAF idle range voltage mapping values back to stock.

I have an HKS panel filter which is supposed to flow more, and the MAF scaling accounts for that.

But at idle, I don't think it should be 15% more...

We will see...

Edited by Infosecdad
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Dropped the teenagers off at Spanish class and grabbed a couple groceries.

 

Not a long test, but plenty of lights to idle at.

Have an LV like this right now:

 

1181476019_BtSsmLearnedValues(4).png.dd76a3973cd4182acd42eceb996c0a50.png

 

Need more drive time, but it's very promising.

First time ever for slightly positive in AF Learning A

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Just finished replacing all the injector o-rings.

Injector #3 was acting up from time to time.

Old o-rings were pretty cracked and tired.

 

Oh, and if you cap off the vacuum reference nipple on Cyl #4 that would have gone to your FPR, replace that cap annually.

Mine was pretty far gone so I replaced it.

 

Need a few more MAF scaling adjustments and some long drives now.

Looks like DC this month and Minneapolis next month.

Edited by Infosecdad
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  • 1 year later...
Just finished replacing all the injector o-rings.

Injector #3 was acting up from time to time.

Old o-rings were pretty cracked and tired.

 

 

OP, did you also do this to your #2? Can't remember if you did.

 

 

I just went through this. never really crossed my mind the orings would fail. (happened to me on #4).

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Are you still experiencing misfires in #2 now?

 

Yes, still only at 0mph.

Clutch in, clutch out, in gear, out of gear, any RPM, any coolant temp... doesn't matter.

Any speed over 0 makes it stop, regardless of the variables above.

 

Yeah, figure that one out.

 

Emotionally I've given up on searching for the root cause. It is what it is.

As the car gets older eventually the misfire will disappear as new parts replace old parts. Or it'll hang around forever.

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ok. What's the peak roughness count again you see at 0mph?

 

 

 

I can't remember all the details.

But you've put new pistons in?

 

What did you exactly do to the driver side head?

 

Ever changed the crank position sensor?

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maybe the day you eventually replace your floor mats, the misfire will go away.
BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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ok. What's the peak roughness count again you see at 0mph?

 

 

 

I can't remember all the details.

But you've put new pistons in?

 

What did you exactly do to the driver side head?

 

Ever changed the crank position sensor?

 

Roughness... maybe in the 40s? 50s? Does the ECU go as high as 60?

I can't remember exactly how high it goes. I'm sure I have a chart in this thread somewhere.

 

I haven't changed any sensors.

 

3 new pistons + 1 reused original (see rebuild for embarrassing reason), new rings, new bearings.

Original rods and crank.

 

Both heads:

Cleaned

Polished (not ported)

Decked

New valves (with correct sized buckets)

Lapped valve seats

New valve seals

Reused original valve springs

TGV's are gone

 

Everything I've done to the engine was after the issue started, so I can be confident that what I've done didn't cause the problem. Maybe I've made it worse, but I didn't start it.

 

maybe the day you eventually replace your floor mats, the misfire will go away.

I could use a new front mat...

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40-60 is a lot. Can't be fake IMO. The count peaks at 99 and goes back to 0 and increments again. From my experience, CEL gets triggered when it reaches 30+ a couple of times in a row or something.

 

 

So I am guessing piston #2 is new with new rings right?

 

 

 

Did you hone your block? I can't find the post in your thread. I mean, 65 pages man :spin:

Could be that even with new piston/rings, the cylinder walls in #2 are no good anymore, thereby not providing a good seal.

Another thing: when you put the new valves in, did you do a 'water test' or with brake cleaner before putting the head back on the block?

 

Another question: have you inspected your #2 spark plug recently and compared it to #4?

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40-60 is a lot. Can't be fake IMO. The count peaks at 99 and goes back to 0 and increments again. From my experience, CEL gets triggered when it reaches 30+ a couple of times in a row or something.

 

 

So I am guessing piston #2 is new with new rings right?

 

 

 

Did you hone your block? I can't find the post in your thread. I mean, 65 pages man :spin:

Could be that even with new piston/rings, the cylinder walls in #2 are no good anymore, thereby not providing a good seal.

Another thing: when you put the new valves in, did you do a 'water test' or with brake cleaner before putting the head back on the block?

 

Another question: have you inspected your #2 spark plug recently and compared it to #4?

 

Yes I honed the block, and all pistons got new rings.

I don't remember which cylinder got the reused piston. That puppy was extremely clean before it went back in though.

 

I tested the heads with the new valves but I can't remember how long I let the water sit... maybe overnight, maybe just a few hours. Either way the valves didn't leak.

 

I don't remember when I last pulled the plugs to look at them. It's still misfiring so I have no reason to think #2 wouldn't look different.

 

I should take a video of the engine running so you guys can see what it looks/sounds like. It's hard to doubt once you see it.

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Well, I hope it is not cylinder #2 who got the reused one.

 

 

Did you try brake cleaner too or just water?

 

 

I guess you probably honed the block yourself right? If yes, then you were not able to measure for roundness, right? Just wondering if the cylinder is ever so sightly oval shaped or something.

 

 

 

Do you burn any oil?

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I sit corrected, I bought the used piston from someone, from a different motor, and it was visibly much newer than my pistons. The skirt coating was almost as good as new.

 

I honed the block using a ball hone.

I did check for roundness... see the attached blank inspection sheet.

I don't remember the numbers but I do remember that the cylinders are not out of round.

 

Even with my minor oil leak (main seal or oil pan?) I don't consume any noticeable amount of oil between 3k mile changes.

Inspection - Cylinders.pdf

Edited by StkmltS
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