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2006 Impreza WRX Limited
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Discussion Starter · #1 ·
Okay guys,

As some of you probably already know I was having some overheating issues due to a bad head gasket and I had a misfire on cylinder 2 that I thought was probably being caused by bad head gaskets as well.

I pulled my motor over the weekend and put in new Subaru OEM gaskets.

I am no longer having overheating issues

I do still however get a misfire code. When I had the head off that cylinder was all brown and i figured it must have just been because of coolant leaking into it and burning in there (causing my loss of coolant and misfire code)

Well... I still getting a misfire code. I swapped my plugs around. I swapped my wires around. I swapped my injectors around. What could possibly be causing my misfire? The car doesn't seem to bog or run rough...it actually feels like it is running very smooth.

I have a brand new front OEM O2 sensor and a used but good rear 02 sensor out of a 99 (mine is an 01) So the difference is that my OEM one had a signal ground wire and the 99 doesn't, but the connector is the same just missing one wire.

Help me please. If there is any more info you need just let me know and I will do my best to provide it for you.
 

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Discussion Starter · #3 ·
Yeah, well when I had the motor out the battery was out for 12 hours or so it got reset then...and I reset it using the tactrix cable a few times since then too.

Oh and I think I forgot to mention it only happens once the 02 sensors are in "ready" mode.
 

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Discussion Starter · #5 · (Edited)
I put all new intake valves in about 5k miles ago... I really hope I don't need exhaust valves too... :(

I took all my valves out and cleaned all the carbon off them and the seats and made sure they sat in there well so... they SHOULD be good. I think I would have noticed if one of them was bent when I was cleaning it since I was spinning them to clean them.

Also I have Delta 2000 cams.

Could this just be a very bad valve adjustment? I did it a few different times to a few different specs but who knows...?

Oh and I did a leak-down test and found no leak-down...
 

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Mobile Diagnosis Guy
97 Impreza L
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5,492 Posts
does the car look like its misfiring? this could be a false misfire reading. Do you have any exhaust leaks?
 

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Discussion Starter · #7 ·
It looks and feels like its running fine. I did however notice that cylinder 2 was brown and burnt when I pulled the head. This could have been a coincidence...could have just been that my coolant was leaking into cylinder 2 and I am getting a phantom misfire code that just HAPPENS to be on the same cylinder...
 

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Mobile Diagnosis Guy
97 Impreza L
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5,492 Posts
Can you look at ECU data?

This is my guess. Coolant contains gylcol which when burned will contaminate an o2 sensor. Anytime I replace a headgasket, i replace the 02 sensors also....

When your o2 sensor monitor goes "ready", that means that the ECU is now looking at those for info. Your o2 sensor is bad and reading a bias lean condition making the ECU think your engine is misfiring...it probably isnt misfiring at all.
 

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Discussion Starter · #9 ·
Yeah I can look at any ECU data using RomRaider...just let me know what and I will take a look...

I just put the new 02 sensor in too...I hope I didn't ruin it already :(

Is there a way to clean or remove the glycol or do I have to just buy another one again?

The one behind the cat should be okay right? Especially since it doesn't look at that for data...just for emissions stats?
 

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Mobile Diagnosis Guy
97 Impreza L
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5,492 Posts
you put new o2 sensors in before you fixed the headgasket or after?

Sometimes, you can clean up o2 sensors....its not guaranteed though. Pretty much you want to heat it up real good to burn off anything contaminating it. Start your car, let it idle and heat up to operating temperature.....rev it by moving the throttle linkage to 2500 or so RPMS. Then create a vacuum leak....i would use the brake booster hose...just take that off. This is going to lean you out pretty far....the car will want to stall so work the throttle to keep it at 2500 or so. Do that for maybe 30 to 45 seconds then reconnect the hose. This might burn off any contaminates in it.

oh and the rear o2 should be good. youd get a po420 code if that was contaminated.
 

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Discussion Starter · #11 ·
I put it in probably 2 weeks before I fixed the HG... I thought a bad O2 sensor was causing my misfire so I put it in...that and I ran water that whole time since I was pissing out coolant daily and didn't feel like spending money on it anymore.

I will try the heating it up trick anyways though. Any ECU data I can check to give me a better idea of whats going on?
 

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Mobile Diagnosis Guy
97 Impreza L
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5,492 Posts
check your long term and short term fuel trims...report back with those. Also check o2 sensor 1's voltage. report back with an average of where it is reading when warmed up. it should range from .1v - .9v...back and forth.
 

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Discussion Starter · #13 ·
okay ill log that stuff tomorrow and let you know what i get.
 

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Discussion Starter · #14 ·
Okay well guys I finally got a chance to work on my car again. I am living at school and barely drive/work on it lately. I got some garage time all day Saturday and I went through and carefully re-adjusted each valve lash to perfection. I have Delta cams so I adjusted to 6 and 8 hundredths intake and exhaust respectively. I actually used 7 and 9 and did it really tight so the 6 and 8 slid in perfectly.

I drove for a while and checked my codes - none. Then I looked at "Pending Codes" and I had a misfire and both cylinder 2 and 4. I got a little worried and thought I made it worse. I then reset the ECU and turned the idle up to 950 and have driven for two days without any codes or pending codes. I think my nightmare is finally over.

Overview of my nightmare -
May 2008 -
-Doing timing belt as preventitive maintanance.
-Lined up wrong mark and bent all intake valves.
-Decided to take the project on myself and pulled the heads and put in new:
valves
valve seals
cams
cam seals
head gaskets
valve cover gaskets
water pump
timing belt
tensioner
all the other little things
-I drove for about a month with no issues then started having a few overheating issues.
-It got worse and worse. I replaced:
Radiator
Thermostat
Rad Cap
Fans
-Finally accepted the inevitable that it was my HG's that I cheaped out on and used graphite.
-Put in all new OEM parts and also an Exedy clutch while I had the motor out.
-Still had a misfire but I re-adjusted my valves and it seems to be good now...in SEPTEMBER!
 

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:::crosses his fingers:::

I'm glad to see that it's finally fixed! It makes me upset to see all the trouble you went through... but you learned a lot from it I'm sure. All your hard work, time, effort and money paid off, congrats :)
 

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Discussion Starter · #16 ·
Thanks. I am crossing my fingers that this is finally the end of it all. It really made me form an attachment to my car. When I first got it it was just so reliable that I drove it...that was it. After pulling the motor and doing all this work to it I really feel like its MY CAR now. I never want to get rid of it now. :)
 
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