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2006 Outback 2.5i manual
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Discussion Starter #1
So, when doing a compression test a couple days ago I noticed that cyl # 4 spark plug has significant white on the electrode ground strap. Seems like that specific cylinder must be running very hot. All other cylinders actually show black on the ground strap, as if they're running rich.

My assumption is that the fuel injector in cylinder # 4 probably isn't spraying as much fuel as the others. To compensate, the ECU must be increasing injector duration causing the other 3 cylinders to run rich to make up for the lean burn in cylinder # 4.

If this is the case, I am thinking that perhaps I could just swap out fuel injectors with either new ones, or remanufactured injectors. Does anyone have any experienced using remanned or new (aftermarket) injectors for the EJ253?

I'm thinking about going with these guys....




I've sent fuel injectors to performance shops to be ultrasonically cleaned in the past, and generally had good experience. According to the above description, it sounds like these have had all that stuff done. The price is about right for that kind of work.

What do you think?
 

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05 GT wagon, 09 Spec B, 18 3.6R Outback
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White build up... are you sure its no coolant ? I seem to recall years ago coolant in the cylinder could cause that.

You can swap your injectors around and see if the issue follows.
 
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2006 Outback 2.5i manual
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186 Posts
Discussion Starter #3
White build up... are you sure its no coolant ? I seem to recall years ago coolant in the cylinder could cause that.

You can swap your injectors around and see if the issue follows.
Appreciate the input!

In the past, on previous cars, I've had coolant leaks which discolored the spark plug, but it usually gives it a tinge of green, along with looking relatively clean (probably due to the hot steam cleaning stuff off it). This white buildup has a classic 'running too hot' look to it. I should have taken a picture!

That said, this doesn't seem like a coolant leak from the head gasket to me... I could most certainly be wrong...

I'm really leaning towards getting those replacement injectors. New seals and having an OEM set that is flow matched and properly cleaned would be a good thing regardless. Perhaps I'll order them, and during the replacement I'll snap a pic of how all the spark plugs look. I'll give it a few hundred miles and then recheck to see if it fixed the problem or not by taking another look at the plugs, then I'll report my findings. If it doesn't fix it, then I'd bet you're right in suspecting a coolant leak.

I'm planning to replace the head gaskets myself probably at the end of summer.
 

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2012 OB , 2017 Impreza
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3,470 Posts
cyl4 is KNOWN to burn exhaust valves. (moreso on turbocharged Subie engines)
...not sure if this would reflect as white on the plug???

Consider SWAPPING the #4 injector with a cylinder which does not have the white on the plug (renew the plugs)...then recheck the plugs in several weeks. This may rule-out injector as the issue.
 

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2006 Outback 2.5i manual
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186 Posts
Discussion Starter #6 (Edited)
Ah, that would make perfect sense. Luckily mine isn't boosted, so the heat cyl #4 sees probably isn't too bad. Plugs are new NGK Ruthenium's as of 3,000 miles ago.

@S.O.B.06xt - I skimmed through your notes of the bypass install. How was the job overall? Do you have pictures of the actual install? Links of where you got the kit? Perhaps it's something I could do when I replace the head gaskets.
 

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Ah, that would make perfect sense. Luckily mine isn't boosted, so the heat cyl #4 sees probably isn't too bad. Plugs are new NGK Ruthenium's as of 3,000 miles ago.

@S.O.B.06xt - I skimmed through your notes of the bypass install. How was the job overall? Do you have pictures of the actual install? Links of where you got the kit? Perhaps it's something I could do when I replace the head gaskets.
Here's what I ordered:
Vems-bypass-kit

There is a pull-down menu to select the car it goes into ... No mention of the outback. I think I ordered the legacy gt version - I may have added a note to my order to give me whatever is right for the outback.

I did the install with the car up on my quickJacks and it wasn't bad. The main thing was getting the right view of the rear of the driver's side head and then convincing myself that I'd found the correct plug to remove.

There aren't many choices ...

Then it's mainly a task of putting the right hex bit with extensions and wobbles so it can be cracked loose - from underneath and behind - so you can see and have room to turn the silly thing.

The other question I had was which heater line (to or from cabin?) - to tee into. I used the post-cabin heater return line but I'll have to look again to point to the right one.

I've also seen kits like this from other shops but I liked the detailed info on the problem and wanted to support this guy.
 
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