Cylinder misfires or bad injectors, please post here.

Got my car back with a cylinder 4 misfire- turned out to be a burnt exhaust valve. -- the block looked great no scaring or abnormal wear. but it was an expensive fix. breaking it in -- hope all is well and i can get another 100k miles anyone with ringland failure as stated its cheaper to by a new block and pray your heads are fine.

Unfortunately due to the tests he had show either a piston ring issue or a valve issue. Either way the engine will need to come out to determine the cause of his 30% leakdown loss.

 

If his engine consumes oil then its almost certain the ring or ringland is busted in 4. When a leakdown is done the cyl chamber is loaded with air at a known psi, you move the crank so all the valves are closed and you watch another gauge to see if it reaches the pressure you put in. It should. If it doesnt air is leaking out of the chamber either because of a leaking valve or busted ringland or rings.

Not burning much oil, but the oil appears quite dark.

 

I got the results from the leakdown.

 

Dry test 95 psi

Wet test 120 psi

Leakdown 95 --> 35 psi

 

All normal in cylinder 2.

120 all around is good. you'd like to see less than 10% change in psi among all cylinders

Replaced the #2 injector (with used unit) and now cylinder #2 misfire is back as well as #4 misfire!. Had burnt/cracked #4 cylinder valve replaced last year due to turbo failure.

 

BMX, where do I go from here? I am thinking troubleshooting (again...grrr):

 

Compression/leakdown

Plugs

Coilpack

sending all 4 injectors to Witchunter for cleaning/testing

 

 

Any help would be appreciated

definitely compression test

 

plugs wont hurt for sure and when the comp test is done you can replace them since you need to take the old ones out for the test

 

maybe switch coilpack 2 with 1 or 3, and see if the misfire follows it

Guy that looked at it six months ago just reminded me that he checked all of those things. Compression was good in all 4. He heard that there is an updated OEM fuel injector and he thinks that may be the fix. I called Subaru parts just now and indeed there is an updated injector.

 

BMX have you heard anything about an updated injector and would I be better off getting DW injectors for the same $$ if indeed injectors are the culprit?

not sure what they mean by updated but injector styles changed in 07+ lgt model years. they are top feed opposed to side feed. you cannot put top feeds in your car without changing a bunch of things around...plug its not necessary IMO. get your injectors cleaned and flow tested and be done with it

If I am certain that the issue is related to rings and/or ringlands, can I not just replace the piston and rings?

 

If I plan on selling the car, do I really do $5k work to it? Can I replace a piston without removing the whole engine? It looks like I can access the crankshaft via the oil pan from below. Can I remove and replace a piston this way?

lololol. the engine needs to come out, no question about this. heads need to come off, 2.5l piston puller needed, pull pistons, hone block, install new. of course you won't be doing this so just a brief, vague, response.

OK, we have established that the engine must come out, no way around that.

 

Including taxes, duty and shipping it will cost me around $2300 dollars to purchase a short block

 

How long will it take to pull out and replace the piston once the engine is out. If I have cheap mechanic labour, this might make sense. Roughly $200 to hone the cylinder. Piston and rings are roughly $250.

 

Seems like I could save close to $1800 assuming that the diagnosis is correct.

 

If I am not keeping the vehicle, is this a better option?

you don't replace 1 piston, you do them all. if you're going to have the work done at all, do all the pistons, do it right, and keep the car.

All right so I am going to throw my hat in the ring here....

 

I have the misfire codes for cylinder 3 and 4. Here is a picture of my ignition coil, my gut instinct tells me to replace my ignition coil bc of the way it looks. But with so many things it could be I am just getting fed up with the lemon of a car I bought.

 

http://i62.photobucket.com/albums/h88/marshallbd/DSCN0151.jpg

 

http://i62.photobucket.com/albums/h88/marshallbd/DSCN0152.jpg

 

http://i62.photobucket.com/albums/h88/marshallbd/DSCN0154.jpg

 

What do you all think?

 

When the msg boards say to switch 1/3 with 2/4 does that mean just swamp the plugs at the ignition coil or swap all the wires?

Personally, I'd say that is in need of some replacement. You might want to verify the resistance listed as acceptable in the spec list in the service manual.

 

Also, I suppose you could try sandpaper on the corrosion to see if it helps. When were plug wires and spark plugs changed out?

Lighty sand the terminals and then buy delectric grease at auto parts store

Personally, I'd say that is in need of some replacement. You might want to verify the resistance listed as acceptable in the spec list in the service manual.

 

Also, I suppose you could try sandpaper on the corrosion to see if it helps. When were plug wires and spark plugs changed out?

 

The spark plugs were changed last week and I don't know when the spark plug wires were change. The last owner said he changed them a few months before he sold the car but I haven't been able to take him at his word thus far. If he did change them I would guess they were cheap ones....Ill research that and update you on the quality of the replacement.

 

I have been using a steel brush to take the corrosion off before I delete the CEL code, usually runs for 30-50 miles before it comes back on. When it does come back on it flashes for a bit before it goes solid and then will flash again.

The spark plug wire is Yazaki 1997 R-16-AIPS

 

I am waiting on a friend who has a multimeter to check the coil.

On Friday, after about 48 hours of owning it and maybe putting a whopping 100 or so miles on it, my 2005 GT Limited started misfiring. Took it to the local dealer who told me 3 of the cylinders were misfiring, but due to the presence of aftermarket parts they didn't install they wouldn't look at it further. Took it to another shop yesterday (Saturday), and they found codes 0301-0304. They did look into it further, and found that the waste gate on the turbo was stuck and said this will cause misfires.

 

I skimmed this thread, and if anyone else had misfiring and the turbo was indicated as the problem (or part of the problem), I missed it, so I'm throwing this out there for posterities sake.

 

EDIT: Subaru mechanics I've talked to (from two different semi-local shops) have doubts that the non-Subie-specific shop that blamed the waste gate has accurately assessed the problem. One of the guys I talked to gave me some things to look at that can rule out Saturday's diagnosis and likely leave me with the same underlying problems most here have had. Will update when I get a final determination on this.

Edited May 29, 2012 by ellyssian
Added new info refuting original bit

New plugs fixed it.

P0301 and P0304 started today. Car bogged down like crazy when i was accelerating hard from probably 40-60pmh.

 

88k on the car. still on original coil packs and 2nd set of plugs (iridiums)

Balls, balls, balls. I think it's a bigger problem. I've replaced my #4 plug, coil, and injector and just threw the code again. What am I looking at boys?

Balls, balls, balls. I think it's a bigger problem. I've replaced my #4 plug, coil, and injector and just threw the code again. What am I looking at boys?

 

 

At least a leakdown/compression test. Good luck!

Well ill start there. And thank you

Well ill start there. And thank you

 

And if you're good there then you're looking at something really big.

 

My compression was fine, but three valves had cooked themselves. Have the valve clearances checked.

I've got a fiber optic camera from a tech at work. Going to take a look at the piston before the comp check. And ya I talked to a Subaru tech and he said might need a valve adj