cylinder #4 misfire

[AZP Installs]

My guess is that it's a bad piston ringland.

 

-mike

[jsmith40a]

why would you say that as opposed to a burnt valve? I am trying to weigh my options whether i should open this thing up or not. Dealer gave me a rough quote of about 2000 k to do just the valve but i am hesitant because of what else they are going to find in there aka bad rings..

[AZP Installs]

Well it's fairly well documented that the 05 LGTs and 05-06 STi motors had some bad #4 cylinder ringlands. That's why I'd put the $ on the ringland.

 

What I would do is have a leakdown test done. This I believe would tell you if it's a bad valve or a ring or piston. They can also scope the cylinder as well.

 

-mike

[jsmith40a]

update (if anyone cares) I called and talked to Subaru of America, because I had all my services (30k,60k,90k) done on time at Subaru dealerships they had me fax my service records in. Meanwhile, I brought my car in to have the work done and they called me back a couple days later saying it was a bad exhaust valve on #4, no piston issues. Fast forward almost two weeks later, I get a call from SOA that they are picking up the tab for the repair, minus $200 because I had them do the timing belt.. SOA did tell me that i needed to make sure i use premium gas, which i always do, but i thought that was funny that they still refuse to accept fault that there engine has a fault.

 

edit: They did forget to connect a PCV hose which caused it to stink like exhaust in the car for a couple days and two trips to the dealership until they found the problem

[Scooby2.5]

Swapped the coil packs and still have the issue. Swapping the injectors in the morning.

 

Its interesting, while it was in the learning state after reset of ECU and new O2 sensors, the misfire was heavy, hitting up to around 40 looking at it with ATR software.

 

After warmed up it would never count more than 4 at an idle and a lot of the time it would idle for 5 minutes without a misfire at all.

 

I did see one at around 40 MPH decelerating down to a stop sign.

 

Anyway Ill see what the injector swap brings....crossing my fingers.

 

Well I finally got around to fixing my misfire today. I had tried a new coilpack to no avail.

 

So I cantacted DW injectors and had them make me a 5th 850cc injector to match my existing four.

 

I swapped it out today and my misfire is TOTALLY gone.

 

Now that I have a fifth injector, I can send the one I took out of the car, in to DW and have it fixed so I then have another spare.

[jpicheva]

Hi Friends,

Add another Cylinder 4 issue to the list. We are 500 miles out of powertrain warranty (63,5xx) and just paid the thing off. :mad:

 

We have a 2006 OBXT Limited - it started idling slightly rough about 2 weeks ago -- no CEL. CEL came on last week indicative of misfires on 2 and 4 -- we took it to the dealer. They found that the injectors on 2 and 4 were "bad". Injectors were replaced. Issues on Cyl 2 went away. Not so much on Cyl 4 -- which is still misfiring and shows compression of 50 psi. They are in the process of breaking it down ($600) to take a look at the piston and rings.

 

I've contacted SOA and they may be helping us out with goodwill coverage of the repair (at least partial). Here's hoping --as I'd like to keep this paid-off car for at least a couple more years.

[AZP Installs]

MAKE SURE THEY HONE DOWN THE CYLINDERS if they end up doing rings/piston on the car.

 

I had my #4 cylinder go bad, they replaced all the rings and the #4 piston. 15-20k miles later they were all low on compression due to the cylinder walls not having been honed down when they did the install of the rings.

 

They ended up putting in a new shortblock for me, but I was still inside warranty at that point.

 

-mike

 

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[jpicheva]

Hi Mike -

Thanks -- will do. The valves on the head were causing the compression/misfire problems. Valve apertures on the head were burnt pretty bad on cylinders 2 and 4. I think they are replacing/reworking the head on the driver's side. I'll definitely ask about the conditions of the pistons on that side and request reconditioning of the interior surface if necessary.

 

Kudos to SOA and Jim Keras Subaru here in Memphis. They have been quick to help and the tech (Mike) has been great with communication. We have a demo 2011 Outback 3.6R as a loaner -- which is making me want a new car.

 

BTW - the SOA field engineer we spoke with on Friday attributes this issue to bad gas (he specifically called out Exxon). We will be sticking to Shell from now on.

 

I'll update once we get more info... stay tuned.

[soccergk01]

i had the same problem... #4 so i changed the plugs... had no more so i figured it was fixed then i started geting #2 so we changed the wires and that did not fix it turns out i had a bad head gasket its a subaru thing... so just keep that in mind

[jpicheva]

Will do. I would imagine we're getting a new head gasket too.

 

BTW - the 2011 Outback that I have as a loaner is HUUUGE. Nice for the carseat and booster seat -- but not nearly as fun to drive as the OBXT. I kind of like the paddle shifters though.

[Scooby2.5]

Well the misfires are back. After running PERFECT for the last 3 MONTHS.

 

As posted above I recently had roughness cylinder 4 that maybe 1 or 2 times threw the misfire code. Usually when the car was cold then it would warm up and was fine.

 

I replaced the coil pack which didn't fix it and then purchased a new 850 injector and then the car was ROCK SOLID. No misfires at all.

 

That was about 3 months ago.

 

Then this week on tuesday I was driving down the highway and the car just starting bogging out. I slowed to make the exit and just when I got to the exit it caught and was fine for the last two weeks or so.

 

Acted like water in the gas or something like that.

 

Then Friday I drove a couple hours away and when I got into town, I had MASSIVE roughness cylinder 4, car would not idle, misfire codes etc but ONLY when BELOW 2200 RPM.

If I was above that RPM it was fine, no misfires or roughness.

 

I went ahead and drove it home, but again when coming into town below about 2200 it would hardly run it had roughness so bad on number 4.

 

Oil Level is Fine even when driven home like this, only uses maybe a quart in 3300 miles, no smoke out the tail pipe at all, still boosts fine etc.

 

So in the last 3 months or so its had, new 850 injector from DW, and new coil pack.

 

I cant get it to run correct at all right now though.

 

Any Suggestions

[Scooby2.5]

So today, I swapped in my 'old' coilpack I changed out in March which didn't fix the problem. Swapped in another injector no go. Pulled spark plug and it actually looked pretty good, I was surprised figured it would have been really bad.

 

I checked the resistance on the injectors as per service manual and they read 11.2 OHMS.

 

I did try checking voltage to the injector connector. With the key on, measureing from the connector to chassis ground I get 12.28 volts.

 

Service manual says it should be 10, but don't really know why.

 

I don't see any smoke and it does NOT puff smoke out of the oil fill tube.

 

Guess its getting taken to the dealer tomorrow. Don't know what else to try.....

[jsmith40a]

So today, I swapped in my 'old' coilpack I changed out in March which didn't fix the problem. Swapped in another injector no go. Pulled spark plug and it actually looked pretty good, I was surprised figured it would have been really bad.

 

I checked the resistance on the injectors as per service manual and they read 11.2 OHMS.

 

I did try checking voltage to the injector connector. With the key on, measureing from the connector to chassis ground I get 12.28 volts.

 

Service manual says it should be 10, but don't really know why.

 

I don't see any smoke and it does NOT puff smoke out of the oil fill tube.

 

Guess its getting taken to the dealer tomorrow. Don't know what else to try.....

 

sounds like what mine was doing with a burnt valve

[Scooby2.5]

Motor is toast, only 30 psi in cylinder 4, pretty sure it is a valve issue. I guess I should feel lucky, 158,000 miles.

 

My subaru buddies keep telling me that if you don't crack the ringland then the number 4 exhaust valve is the other problem

 

Also why we were at it we checked number 2 since its on the same side and it was at 120 psi which is low.

 

So car is being trailered to Cobb plano for them to put the new short block and rebuild the heads.

 

 

I firmly believe the problems with number 4 are due to fuel starvation, and number 4 leaning out causing detention and heat from the lean condition.

 

They told me (great mechanic friends of mine at local dealer) they see this all the time.

 

1. Burnt exhaust valve in turbo cars #4

 

2. Head gaskets in N/A 2.5 cars ( you should see the head gasket they are using on the non turbo's now. Its a JOKE)

 

3. Failed ring land on number 4 turbo cars.

[AZP Installs]

Yup at our shop at the first signs of an issue we do a compression test. On the subies it's a safe bet and we may actually start to incorporate this with our 60k/120k services or anytime we pull the plugs just as a precaution.

 

-mike

 

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[noahsstang]

I have a 05 legacy gt an I get a missfire on cyl 1 and 4. It only does it past 4000 rpms at full throttle all I have done to it is a cold air intake an it did it before I put that on. An it has got a lot worse lately an the check engine light flashes bout 10 times an goes back off any ides. Already put new plugs in it an it has a new coil pack on cyl 4.

[AZP Installs]

Compression test it yet? Swap fuel injectors with 2 and 3?

 

-mike

 

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[Ryan]

I just took home my 2005 LGT 5EAT last week. Within a week I have a misfire on #2. The dealer just replaced the turbo because the bearing blew up since he had it a good 5 months and probably didn't run it that often.

 

I checked the records I got that the dealer received from the previous owner and they got the same code for #2 back in January (a few months before the dealer got it), and at that time they replaced the spark plugs all around and the coil pack on #2.

 

I did buy an extended warranty, and kind of thinking that was a good idea after reading this thread with the cyl #4 issues. My idle is fairly rough, but stays above 500rpm. Sometimes hesitant when you hit the gas from a stop. The rest of the drive seems smooth and accelerates like a bat out of hell at WOT, so I'm hoping its just that injector. Letting the dealer work with it for the next few days though. Keeping my fingers crossed.

[AZP Installs]

Any luck on this?

 

-mike

[Ryan]

My dealer's mechanic agreed it's probably the injector, so they're going to replace injector #2 this week. We'll see what that clears up. I'll report back with what I get.

[noahsstang]

Anybody have access port for sale

[ginsberg]

I've been having the same problem. It is only noticeable when going uphill, because it robs you of acceleration. Compression in 4 is the same as the other three, plugs are new, replaced the coil pack on top as it was shorting.

 

Problem went away for say two weeks, but is now back in full force. Code is always cyl 4 misfire. After reading above, you think it might be the injector?

[20lgt06]

Try swapping injectors with another side, and if that doesn't shift you codes check/ change your intake Manifold gasket perhaps.

I've been having the same problem. It is only noticeable when going uphill, because it robs you of acceleration. Compression in 4 is the same as the other three, plugs are new, replaced the coil pack on top as it was shorting.

 

Problem went away for say two weeks, but is now back in full force. Code is always cyl 4 misfire. After reading above, you think it might be the injector?

[DoDo1975]

Sounds like the OCV on the drivers side (#2 & #4 cylinders) could be the problem. It's a pretty easy fix. Other than that, you could have a compression test done to see if you have a burnt valve. That's what happened to my car. I should get it back tomorrow.

 

Where can I find procedure on replacing the OCV. I can't find it in the service manual.

[ginsberg]

Try swapping injectors with another side, and if that doesn't shift you codes check/ change your intake Manifold gasket perhaps.

 

word, thanks. I'll try that this weekend. I let the problem persist long enough last time that the misfires burnt out my clutch plate. Spent more on the new assembly than I would have on cab rides haha.