cylinder #4 misfire

[VTownGT]

Well, I got the final post mortem on my ex-Legacy. Turned out to be a ring (cracked/broken) on one cylinder which caused some scoring to the walls and a carbon fouled exhaust valve on another. The estimate to fix this was $5-$6k (basically a rebuilt motor). This doesn't include the clutch or the brakes which would have needed replacing this year. Good thing I dumped that turd while I had the chance. Having read more and more stories about aging Legacys, I'll never buy another one and I won't suggest to anyone else to buy one either. Long live the Dodge Ram 1500 Hemi.

 

I ended up doing the fix, but I agree that, after this Subaru, I will not buy another one again. I took the best possible care of this car. No maintenance was skipped, and the best fluids were used, etc., and just when I thought that I had a great car (I even posted about how great the car was before the engine went to hell), I got this.

 

If I was the only one, or it seemed like a rare problem, I would chalk it up to bad luck for me and a few others. But there are many on here who have had this same problem, and the guys who did my repair work both mentioned that this is not a rare problem. I recommended Subarus to an untold number of friends and family, and now I feel uneasy about having offered that advice.

 

Ohh, and to top it all off, I changed the oil today, and saw that the passenger's side axle boot was split and there is grease all over. humph...

[McDowell Performance Tunin]

Out of curiosity, did you ever check your oil line banjo bolt screen for cloggs? You also have an 05, which was the first year of the new model and unfortunitly first year re-models are more prone to problems. I've also had some issue's on my 06, but everything was done under warranty so I was lucky. There are always lemons out there and when problems come up, they tend to be magnified, in general, in forums because it seems most people are not as passionate about cars as us forum folk. Regardless, when it happens to you it's going to leave a bitter taste in your mouth, so it's understandable. But, in general, they're not the worst cars on the road (02-03 SE-R Spec-v...much, much worse). Hope your next purchase finds you better.

[AZP Installs]

So... Its been a while since I updated. I had Misfires on #4 all the time, and sometimes on 1 & 3 and some engine squealing. What I was hoping to just be a stretched timing belt and a noisy throw out bearing was actually (almost) the worst it could be...

 

I had to replace the short block. The crank bearings were wearing which was putting some metal into the mix of problems, and in addition, there was piston damage on #4, causing misfires on that cylinder and the others. I did not even try to find out if the block was repairable, I just went for a new short block because it would give me piece of mind. The only way that it could have been worse would have been if the heads were screwed up, too. Luckily, they weren't because I would have not gotten the car fixed had that been the case.

 

The repair work was done at EFI Logics up in CT, who are like a jar of awesome sauce. (I called them on the recommendation of Mike P from AZP Installs, who is like two jars of awesome sauce. More on this below.)

 

It was worth getting the car fixed 100 miles away because as soon as you walk into EFI, you know that all they think about are Subarus. I originally took the car there thinking that the problems were somewhat minor, and when they looked at the car and realized that it was a bigger deal, Chris from EFI called me, asked me a ton of questions about the history of the car (to see if I had bought it used and had been scammed, etc. I let him know I took delivery new with <10 miles.) Then he and Pete laid out my options, costs, put the whole thing in writing, and did the work faster than they promised, which was refreshingly great service.

 

Regarding Mike at AZP... he deserves your business. When I was trying to figure out what was wrong, he met me late on a Friday night at his shop in NJ to look at the car with one of the other AZP guys. Then, he recommended some inexpensive things to try first before getting the above work done, helped me order parts cheaper than I could get them myself, AND, to top it all off, he would not take money from me when I offered to pay him for his time.

 

(If there is a place on the forums where I people are most likely to see my feedback about these two businesses, please someone let me know.)

 

So, the bottom line... about $6400 for everything. That included the short block, all belts, all gaskets, a new clutch kit, an new and upgraded oil pick up, higher quality head bolts, all fluids including three oil changes, spark plugs, and probably some stuff that I am forgetting to list and the labor.) If I include the costs of things that I tried myself to fix before I went to EFI, my total costs are probably in the low $7000 neighborhood, along with a lot of my own time trying to fix stuff myself and and a lot of favors owed to people who were kind enough to drive me around while I had not car for about a month.

 

Thanks for the kind words. We are enthusiasts and love to help folks out. I'm glad to see the car up and running again! Hopefully that axle/ball joint will get fixed soon!

Let me know if you need the ball joint as we have a ton on the shelf. Worst case bring down the LCA and we'll get that sucker out.

 

-mike

[Draug]

Well, my '07 Legacy GT (with 58K miles) is throwing misfire codes on cylinder #1 and #4. Assuming (wrongly, as it turns out, if it's injectors) that such a problem would be covered by warranty, I went straight to the dealer. It's been three days, and they are still diagnosing the problem. I should have went straight to the forum.

 

With both cylinders misfiring, I doubt its a cracked ring or bad cylinder. Also, the code seems to only be thrown on a cold startup, about 45 seconds into runtime.

 

The dealer has replaced the coil, replaced the sparkplugs, and done a compression test that came back ok.

 

Is there anything else this could be other than the injectors? The dealer said they are going to mess with the injectors this afternoon.

 

If the injectors prove nothing, they are going to trying and adjust the variable valve timing to see if it moves the misfire code to another cylinder. If it does, what does that mean?

[McDowell Performance Tunin]

You don't see too many cases with #1 and #4 misfiring, since they are at opposite ends of the engine. the vairiable valve timing, (AVCS) shouldn't be the source of the misfire. The OCV (Oil contol valve, car has two, one for cylinders 1&3 and 2&4, is a likely cause of the misfires, if it's nothing else.) You are using at least 91 octane, right?

[Draug]

Yeah, the car has seen nothing but Premium fuel, ever. Full synthetic oil, etc, etc ...

 

Subaru Canada told the dealer to try the AVCS before the injectors, so the dealer wouldnt change that course of direction. I should know within the next 2 hours if its either the AVCS or the injectors.

[AZP Installs]

Interesting. Keep us posted.

 

-mike

[Draug]

As planned, Subaru checked the AVCS next. They found one was advancing the timing 8 degrees and one was advancing 3 degrees. It stands to reason they should at least be the same (and probably shouldnt advance at idle???). Given they are different, they are optimistic that this is what throwing the misfire code. They couldnt get it back together by the end of business Friday, but I should know more Monday.

 

I should also note that only one cylinder, #4, is repeatedly firing the mis code. #1 was in there the very first time, but has not been replicated since they starting diagnosing the problem.

[Draug]

So, the saga continues...

 

They swapped the AVCS units from side to side, and they both reset to 0 degrees, where they are supposed to be. But, the engine code is still getting thrown for a misfire on Cylinder 4. It is interesting to note that it only happens on warm up.

 

They also swapped the injectors, swapped out the oxygen sensors, and swapped out an Air Fuel Mixture celenoid. Previously, they changed the spark plugs, coil packs, and had a compression test which was OK. All their testing has resulted in the same thing; a misfire on Cylinder 4.

 

The dealer claims that Subaru Canada Tech. is now suggesting to put in a new ECU "because that is all it really could be". It honestly seems like they are grasping at straws here... The cost on the ECU is over $1000, and they want me to pay for it even if it doesnt solve the problem because they dont have one in stock. Im not really willing to pay $1000 so they can continue their guess and test method of research here...

 

Any other ideas what it could be?

[AZP Installs]

I take it you are out of warranty?

 

My guess is that it's the wiring harness.

 

The clips tend to snap on the coil packs. We've seen misfire codes that won't go away after a 60k service due to the clip snapping. We finally wind up supergluing them and they are fine.

 

If you've moved around stuff like injectors, plugs, etc. Then it could be:

Wiring in the harness that go to cylnder #4, or a sticking valve perhaps, or ECU.

 

-mike

[Draug]

Strangely, Subaru USA said the ECU fell under the Emiission warranty (8yr/60K miles), so I am still under that... but I think they are mistaken. However, they said if (and only if) the ECU was the problem would the cover it.

 

But, being that it is an American car imported into Canada, I have to pay for all repairs first, and then submit my expense to Subaru USA.

 

My fear is that they order the ECU, put it in, and then the problem persists. In that case, they are saying I would have to pay for the ECU. I've already told the dealer that is NOT going to happen, so they are currently "seeing what they can do for me".

 

I see what you are saying about the clips. But, the harness had never been off the coil packs before the codes were thrown for the first time. Are they something that would fail if they were never touched? With my luck, the dealer has probably broken them by now after all this messing around...

[AZP Installs]

Generally if they weren't touched they shouldn't have broken, but maybe when someone did the 30k service they replaced the plugs, in which case they would have come off (you unclip them to do a plug change).

 

It could also be a failure in the wiring harness as well.

 

-mike

[Draug]

Generally if they weren't touched they shouldn't have broken, but maybe when someone did the 30k service they replaced the plugs, in which case they would have come off (you unclip them to do a plug change).

 

It could also be a failure in the wiring harness as well.

 

-mike

 

Still no resolution ... The dealer found an used ECU, but still wants me to pay for it if the ECU is not the problem. I have a huge issue paying for a part that turns out to not be broken and have refused to this point, and have been escalated up the Manager chain. I expect that the next manager will tell me either to take the car as it is or accept paying for the ECU whether it fixes the problem or not.

 

It seems that the common consensus is that it must be the wiring harness if it is not the ECU. The wiring harness has never been touched until now; all the service (with the exception of coolant flush and the transmission oil change) has been done by myself. The sparkplugs haven't been changed until the investigation of the misfire.

 

You mentioned it could also be a sticking valve. Is there any way to test that easily?

[AZP Installs]

Sticking valve should show low compression in that cylinder.

 

On a side note, my car is in for a new short block under warranty at 97k miles. Subaru Added Security is stepping up and replacing the block due to low compression across the board, 20k miles after doing the rings and 1 piston...

 

-mike

[TFBHTMFSNE]

Seems to me all they did was just hook up the computer, run a quick compression test, and call it a day. What bothers me the most is that they want me to make a $1400 decision based on $93, basically an hours worth of work, on shoddy, half assed trouble shooting. Honestly, I would be ok with spending a grand having the car fixed if I knew it needed valve work (multiple thousands on a new engine, not so much), but I need to know up front what I am dealing with before I'm willing to part with that kind of money, and I am just not that williing to spend $1400 on tearing an engine apart to just turn around and sell it because it needs an engine rebuild. I think its shameful on Subaru's part to sell a car that is disposable after only 62K miles.

 

Uhh, no offense intended here, but - you stated you've been a mechanic for almost 30 years, had a shop tell you that compression was low in #4 cylinder, you then swapped out a bunch of parts, and now you're complaining about "shoddy, half assed trouble shooting"?

 

What exactly would you consider good troubleshooting? Waving a magic wand over your hood and fixing your car for free?

 

The car was repairable, not disposable. Get real.

[jmorris6689]

I have a cylinder number 2 misfire code, i just put new ngk one step colder plugs in it maybe 15000 miles ago, i wasent have any problems before i put the plugs in but Im running over 100hp extra from the factory. now at 52000 miles i have a rough idle and it get worse when i turn the ac on. when i drive it drives fine. i just bout some 850cc injectors but im not putting them in until i buy my turbo and have money to tune it all. should i try replacing just the plug?

[AZP Installs]

I have a cylinder number 2 misfire code, i just put new ngk one step colder plugs in it maybe 15000 miles ago, i wasent have any problems before i put the plugs in but Im running over 100hp extra from the factory. now at 52000 miles i have a rough idle and it get worse when i turn the ac on. when i drive it drives fine. i just bout some 850cc injectors but im not putting them in until i buy my turbo and have money to tune it all. should i try replacing just the plug?

 

Check the wire to the coil pack. They tend to fail due to being a bit brittle. Could also be an alternator issue. Could be a gap issue as well.

 

-mike

[nka]

Failing alternator could cause that issue?

 

Mine is doing a wierd noise, I was trying to stretch it as long as I can... I will change it then!!

[Scooby2.5]

Add me to the list, my car started to have an intermitant misfire on cylinder #4 about 2 weeks ago.

 

It was due so I changed the O2 sensors, the spark plugs (which looked flawless) and also the FPR due to a possible low fuel pressure problem and stumble at idle.

 

The AVCS solenoids have been replaced in the last couple of months as well.

 

Getting rough idle, can hear a pop misfire once in a while at idle and now every now and then the misfire CEL.

 

Ill be swapping injectors tomorrow to see if that fixes it and then coil packs.

 

Whats this about the alternator AZP?

[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.

[AZP Installs]

Add me to the list, my car started to have an intermitant misfire on cylinder #4 about 2 weeks ago.

 

It was due so I changed the O2 sensors, the spark plugs (which looked flawless) and also the FPR due to a possible low fuel pressure problem and stumble at idle.

 

The AVCS solenoids have been replaced in the last couple of months as well.

 

Getting rough idle, can hear a pop misfire once in a while at idle and now every now and then the misfire CEL.

 

Ill be swapping injectors tomorrow to see if that fixes it and then coil packs.

 

Whats this about the alternator AZP?

 

If your alternator were failing, at high RPMs it won't put out enough amperage to drive the coil packs... Rare but I've seen it.

 

-mike

[jsmith40a]

Add another cylinder 4 misfire to the list. Ive done the plugs, injector and coil pack and the problem persists. Anyone know of a reputible shop in south Jersey nearish to Atlantic City? Teh dealer wants $120 to do a compression test and this dealer has screwed me before so I don't really want to give them my business. I hoping just for a burnt valve. Anyone have prices on what it cost to replace the exhaust valve so I have a ballpark figure? AZP - do you do valve jobs?

 

Edit: Car is stock except for a Momo shift knob.

[AZP Installs]

A compression test would be a good start. That would tell you if the issue has to do with the engine itself or if it's something electrical in nature. After that a leak-down test would help you narrow it to a valve or a ring.

 

When I had oil consumption issues on my 05 LGT, eventually it led to a #4 cylinder ringland failure or was a result of a ringland failure, I was not getting any misfire codes. The compression in that cylinder however was significantly lower than the other 3. When they replaced my shortblock, about 10k miles after doing the rings and pistons, they figured out that it was due to the failure to hone down the cylinder walls when doing the rings.

 

We don't do any internals, if I had to hazzard a guess, a valve job would not be in-expensive, just because the motor needs to get pulled IIRC etc.

 

$120 to do a compression test is about right, but if you can't trust em, then it's worthless. We charge $120 to do a compression test or $150 w/new plugs. It's a bit of a hike to come up to us or I'd suggest it.

 

-mike

[jsmith40a]

Mike - thanks for the info, at least now i know that 120 isn't a rape for a compression test.

[jsmith40a]

welp, just got the prognosis. #4 cylinder running at about 50 psi....