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06 Forester 2.5 210,000 mile club, 01 Outback 2.5 182,000 mile club
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Discussion Starter · #1 ·
Hi. Its been a long time since I posted a message about my Subaru Outback but I have a problem and am just looking for a little direction. Last week I was driving in the rain, running just fine. I started up a mountain at 55 MPH and just started losing power. I gave it gas, it downshifted and I could feel a noticeable vibration coming from the engine. The CEL was blinking. I limped it home and it kept stalling every time I lifted off of the accelerator. That night read the code, #4 cylinder misfire. I figured it was an easy fix so I popped a new plug in it, started it and it would sputter and die. Not so easy of a fix after all. I replaced all of the plugs the next day, started it and this time it would stay running but the idle is surging between 1000-2000 RPM...exhaust smells extremely rich, kinda feels like there may still be a miss. I let it run for a few minutes, backed in and out of the garage...no CEL. I started reading threads on here and found a few that suggested disconnecting the upstream O2 sensor (I read they go bad and sometimes cause my symptoms without a CEL). So I did that...started it and I have same problems and surprisingly no CEL even though the O2 sensor was disconnected. I didn't let it run long because of the rich gas fumes coming from the tailpipe. I don't want to damage my Cat because it was replaced 2 years ago. I am not sure what direction to go with this. I hate just changing parts...just looking for some advice on which way to troubleshoot. Plugs are NGK, brand new, wires are 1 year old, coil 2 years old...engine was rebuilt in 2016 and has been great ever since. Thanks for your help!
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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was there oil on the plug wire boot? leaking valve cover seals can let oil short out the ignition.

how old are the plug wires? they can sometimes fail/arc in moist conditions.

plugs and wires really need to be OEM or equivalent.

sometimes there are pending codes and scanning can be useful even if the CEL is off.

miles on car? time since timing belt service?
 

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06 Forester 2.5 210,000 mile club, 01 Outback 2.5 182,000 mile club
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130 Posts
Discussion Starter · #3 ·
no oil on the boots, I just rebuilt the engine 17K miles ago...

wires are less than 2 years old...supposedly a high performance grade of wire (8mm)

182,000 miles, timing belt changed at 165,000 when I did the engine

Like I said in the original post, exhaust is very rich smelling...no CEL even with an O2 sensor unplugged from the harness.

Thanks for the quick response
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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scan for pending codes

bad coil would compromise ignition in 2 cylinders due to waste spark ignition scheme but i read where it is fairly new

I can;t explain why a code hasn't been set, but there can be codes pending

doesn't 'seem' like a sensor is bad, more like a 'hard' failure, slipped timing? could an injector be stuck open???
 

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2008 OB Limited 2.5i, Portland OR USA
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Air intake partially blocked? What's the air filter look like? I know this one is a long shot, since it was such a sudden onset with the issue, but at least it's very easy to check out and eliminate as a cause.
 

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06 Forester 2.5 210,000 mile club, 01 Outback 2.5 182,000 mile club
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Discussion Starter · #7 ·
OK, thanks for the feedback. I will take a look at the air filter to see if anything looks obvious. Its garage kept so hopefully I don't have anything trying to live in there! I have also scanned it looking for pending codes...nothing. I will take the timing cover off and take a look at the timing belt to rule that out. I do have a second coil that I could also put on there to rule out the ignition coil. Originally I had thought about the #4 injector being faulty since this was so sudden and it happened when it downshifted and the RPM went up. I will get a look at these things this week and report back. Luckily this is a spare car so I am not under pressure to get it fixed fast. Thanks so much for the help. Any other advice out there, I will gladly listen.
 

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2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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what kind of coil by brand? (subaru like OEM, that says "subaru" in small letters etched in the front. and any aftermarket that may work, costs just as much or more then the OEM. ....I would even try a used $20 pick and pull OEM over a aftermarket).

what brand are the wires: hopefully NGK, or something sold by a subaru dealer.

I would not think it is a front o2 sensor as they make for multiple minor misfires. not just one cylinder.
if you have a windows laptop and a $10 VAG cable you can try rom-raider like I did though:
http://www.subaruoutback.org/forums...89-p0130-2002-ej251-climbing-grades-fast.html

(free SSM may not work with a 2001, and rom-raider shows a lot more anyway)

I wonder if it could be a single stuck injector. or unequal fuel pressure on each side of the engine.
- rom-raider would show that I think.
 

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Discussion Starter · #10 ·
Yes, my misfires from before were a long drawn out saga that revealed every kind of issue that can cause misfires. I did a lot of troubleshooting that fixed many minor issues but the end cause was the #2/4 cylinder bank was 1 tooth out of time and the #1 connecting rod bearing had excessive play. You may wonder why I included the connecting rod bearing play...well, it failed and that is when I disassembled the engine for a rebuild. Since that time the only running issue I have had was the knock sensor failed. I was reminded of that when I had my head buried in the engine reconnecting the O2 sensor and I was starting at that sensor. Its funny, when it failed the car would start and stall...ran like crap but did not throw any codes. I actually changed it because it had popped a CEL twice before as a knock sensor code. The second time it threw the code I ordered one just to see if it was really bad. The day before it arrived in the mail, the car did what I just described, start and stall, ran like crap. I changed the knock sensor and it ran like a champ. That was about a year ago and I kinda forgot about that until I was just face to face with it. I just checked the air cleaner and timing this morning, both are ok. The first suggestions were air filter, timing and coil. Since the other two were fine, I put the OEM coil back on it because when I changed it about 3 years ago, that wasn't my problem. It had been an after market coil...the OEM is back on it. Wires, I really don't remember where they were from because so much went on in 2016 with this car and my life. I am going to start it in a bit...just sipping on my last cup of coffee and warming back up. Wires will be my next step.
 

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Yes, my misfires from before were a long drawn out saga that revealed every kind of issue that can cause misfires. I did a lot of troubleshooting that fixed many minor issues but the end cause was the #2/4 cylinder bank was 1 tooth out of time and the #1 connecting rod bearing had excessive play. You may wonder why I included the connecting rod bearing play...well, it failed and that is when I disassembled the engine for a rebuild. Since that time the only running issue I have had was the knock sensor failed. I was reminded of that when I had my head buried in the engine reconnecting the O2 sensor and I was starting at that sensor. Its funny, when it failed the car would start and stall...ran like crap but did not throw any codes. I actually changed it because it had popped a CEL twice before as a knock sensor code. The second time it threw the code I ordered one just to see if it was really bad. The day before it arrived in the mail, the car did what I just described, start and stall, ran like crap. I changed the knock sensor and it ran like a champ. That was about a year ago and I kinda forgot about that until I was just face to face with it. I just checked the air cleaner and timing this morning, both are ok. The first suggestions were air filter, timing and coil. Since the other two were fine, I put the OEM coil back on it because when I changed it about 3 years ago, that wasn't my problem. It had been an after market coil...the OEM is back on it. Wires, I really don't remember where they were from because so much went on in 2016 with this car and my life. I am going to start it in a bit...just sipping on my last cup of coffee and warming back up. Wires will be my next step.
post one of that older thread says you got Denso wires on there. so you might actually review all the steps you went through in the old thread and check the boxes again.
 

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06 Forester 2.5 210,000 mile club, 01 Outback 2.5 182,000 mile club
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Discussion Starter · #12 ·
So I ran the car...still the same, starts right up but surges between 1200-2000 RPM after cold startup with rich exhaust fumes. I let it run for about 4 minutes and no CEL. I have an interesting observation though...I gave it some gas and held the RPM at about 3000...then engine sounded good and the exhaust smoke seemed to subside. I held the RPM for about 30 seconds there and things felt normal. I let off of the gas and the idle surged between 1000 and 1200 RPM with rich exhaust fumes and it was wanted to stall...This has me thinking it may be an injector since it was all of the sudden and I have no CEL. Any suggestions?
 

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Discussion Starter · #14 ·
I will try it tomorrow. The battery is disconnected now...I will let it sit overnight and see what happens tomorrow after work.
 

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Discussion Starter · #15 ·
Update: after 24 hours of having the battery disconnected, the start up proved the same symptoms. The car starts up, surges between 1200-2000 RPM and has a very rich exhaust smoke coming out of the tailpipe. When the throttle is picked to to 3000 RPM the running sounds better and the rich exhaust fumes subsides almost completely (no visible rick smoke is coming from the tailpipe). I didn't let it run long out of fear of damaging the CAT with rich exhaust fumes. Still no CEL. Someone pointed out that I have aftermarket wires on it so I have OEM wires on the way. When they arrive I will post an update. Keep the thinking caps on and if you have ideas, let me know. I may actually attempt to drive it after putting the new wires on it to see if I can get a CEL but again after the CAT bill the first time, I am not interested in replacing it anytime soon, LOL. At this point I believe it was a sudden failure of a part...at least that is what it seems. Thanks for the help, keep it coming!
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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the fact that you have the same symptoms when the car is running on the factory map after a reset lends some evidence that A:F sensors may be OK and this is a more 'physical' problem.
 

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Discussion Starter · #17 ·
What kind of physical problems are you thinking? Fuel injector? Something else? Seems to run good at 3000 rpm, just not at idle, very rich...Wires arrived today but I won't get to them until Saturday.
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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vacuum leaks, leaky injector, fuel pressure issue, gummy throttle plate....something that isn't a bad sensor.
 

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Discussion Starter · #20 ·
I checked the vacuum lines...replaced every single one of them two years ago so I know where they all are...connections are nice and tight and the rubber is still pliable. The throttle plate has a little oil on it so I can get that cleaned up, no problem. I can check the fuel pressure...I will do that after I change the wires and do a another test run. I checked the timing in an earlier post, all marks still line up. After my next test run I am going to pull the plug on the #4 cylinder to see how it looks. I will have to pull the others to see how they look too. If the #4 is already black from running too rich and is different form the other 3, I will start with suspecting that injector as possibly being a problem or something in that cylinder. If they are all black, I will have to look for something common to all cylinders (maybe fuel pressure or something else). Those plugs have been in there for about 15 minutes of running, I would think if the cylinder is running good the plug should still look new. Thanks for the advice.
 
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