Were to go next?? P0301 Cyl. 1 misfire

[Popeye.Tom]

Hi all,

This car (2007 Outback Wagon, base) was purchased a few years ago with a blown engine.  I put a used engine from LKQin it.  It got new timing belt, head gaskets, oil & water pumps etc before going in.  It's been pretty good, all things considered.  But ,for a long time I had nagging Cyl.1 misfire and a cat efficiency.  I'm managed the cat, but not the misfire.

>>  I did see some fouling on the plug from #1 yesterday...  <<

I have since putting in the used engine, I have done the following in the past 12 months...

- Exhaust (not factory dealer)

- Plugs, NKG (I'd have to look at which p/n

- Plug wires, Belden - they didn't have the NKG and when I did the plugs #4 wire broke at the plug & couldn't wait

- radiator

- reman injectors (last weekend)

I have run two cans of Jectron cleaner through with full tanks of fuel.

The bloody check engine light will go out periodically.  It has been out a couple of times (on it's own) since doing the injectors, but it comes back.  I cleared codes yesterday and it came back about 30 minutes (of driving) later in the second run time of the short trip. 

I pulled 1 & 3 yesterday evening.  Plug 1 did show not as clean & correct color as 3.  Some fouling, can't say if it was oil or rich.  I swapped 1 & 3 plugs when I put them back in, I'll have to pull and look at them now.

I measured resistance for the Belden wires on 1 & 3 and they were close to each other and correct range for radio suppression wires.

The engine definitely seems smoother at cold start idle after the injectors and I thought that was the end of P0301, but no!  I do find it is idling low and rough after the code reset yesterday, but maybe that's just the system learning again.

 

>>> I have run run a compression test.  I will do that and report the numers.  Maybe #1 is simply dead, but the car can get average 25 +/- mpg in general driving and low 27+ in highway, doesn't seem like numbers for a 3/4 good engine!

 

>>> I've not replace the coil.  Do I just do that next?  (it is not COP, unfortunately)

??? This has the little 4 square coil pack and regular plug wires. Is this a "waste spark" type ignition and is there another "corner" of the coil I can swap out plug wires for a test?

 

Please make suggestions for next steps!  Parts, tests.  Where would you go with this next?  My daughter has been driving the car to school & the tabs have expired and I cannot pass emissions with the Check Engine on!

 

Thanks,

Tom

[Popeye.Tom]

Oh, it is a 2.5 AT car.

Thanks in advance for your thoughts and ideas!

Tom

[brus brother]

try swapping 1 and 3 wires to see if the fouling travels with the wire.

Edited April 3, 2021 by brus brother

[idosubaru]

Is it consuming oil?  Replace PCV with Subaru OEM.  It won’t help but it’s easy and cheap and routine maintenance anyway.

check fuel pressure.  Shouldn’t impact one cylinder, but #1 is furthest from incoming fuel line....

I had a misfire on a 2003 Forester that wasn’t fixed with plugs/wires/coil.  I had an extra intake manifold and swapped the entire thing and that took care of it. No idea what it could have been.  Vacuum leak/hose, throttle body, coolant temp sensor (though I can’t think how that could impact one cylinder...

Ideally you find a way to test. 

Yes it’s my understanding (which isn’t very good on this point) that coil issues usually result in multiple cylinder misfires...but I’m unsure. I’ve never seen it happen. 

[1 Lucky Texan]

yep, waste spark. if a coil is bad, it affects cylinders in these specific pair-combinations; either 1&2 OR 3&4 .

 

does the car start just as quickly after sitting overnight (or for several hours) as when starting after just a few minutes? Wondering if that one injector is 'leaking-down' .

[idosubaru]

6 hours ago, 1 Lucky Texan said:

does the car start just as quickly after sitting overnight (or for several hours) as when starting after just a few minutes? Wondering if that one injector is 'leaking-down' .

First post reported reman injectors installed. 
did the 301 symptoms stay exactly the same before and after the injector swap?

 

13 hours ago, Popeye.Tom said:

do find it is idling low and rough after the code reset yesterday, but maybe that's just the system learning again.

>>> I have run run a compression test.  I will do that and report the numers.  Maybe #1 is simply dead, but the car can get average 25 +/- mpg in general driving and low 27+ in highway, doesn't seem like numbers for a 3/4 good engine!

??? This has the little 4 square coil pack and regular plug wires. Is this a "waste spark" type ignition and is there another "corner" of the coil I can swap out plug wires for a test?

I find 2005-2009s rough idle sometimes after battery swaps, low batteries, etc. 

compression will test fine. Test them all identically with full battery charge and all other things equal (don’t test one with plugs all out and another with the rest all in, throttle body, etc) and see what variance you get - it’ll be a few percent different between cylinders or identical.  Almost no way you will have a dead cylinder unless that engine saw some weird things in the past. 

You can swap plugs wires and injectors to test 

[Popeye.Tom]

Hi all,

1 - Thank you one and all for the replies and suggestions!

2 - Many apologies for the "run silent, run deep"  Buried at work and spring chores and getting back onto looking at the computer after 10+ hours then chores isn't something I could bring myself to...

3 - I am kicking myself for not doing some other basic tests (like a compression check) or leak down.  I do not have a leak down guage, but the root cause appears to be a failed cylinder 1.  I see only ~60PSI on 1 and 180-210 on the other 3 cylinders.  :-(

A friend (good friend) actually loaned me his bore scope.  Not easy to use, at least for my first time.  With the right angle mirror it seems hard to get a clear view.  I could identify an open valve in one or another cylinder & the residual crosshatch is clear on tops of bore and sides, harder to see the lower "face" of the bores since the cable droops (I think.) 

BUT after fiddling and playing around, I think the bottom face of #1 is smooth, no crosshatch remaining and also has some micro-pitting of the wall.  Now that I've actually read the instructions, I'll go back in and see if I can take some pictures that show anything and I'll post them.

@brus brother  I didn't swap, replaced coil and no change (this like everything else I tried was before I ran compression - I 's a dummy that way!)

@idosubaru  * It wasn't using oil in any appreciable amount.  My daughter was putting in about 1 quart / 6 month change, maybe 4k miles.

                         * I didn't check fuel pressure. 

                          * Did notice that #3 was leaking at the rail, put some reman injectors in and will rebuild the ones I took out, test and save as spares. >> NO Change on #1 miss.

                         * Besides compression test, did run w/ vacuum gauge on intake.  It was not stable - could see "vibration" in intake vacuum.  Also, could hear the miss in the exhaust (stock mufflers) at idle.

NOW I will pull the engine.  Don't think I'll try to rebuild - have too many other projects for that.  This was an LKQ used engine.  I have not tried a JDM pull before.

New Questions - (If I've not burned my bridges w/ slow update)

A- What are your thoughts and experience on JDM pull.  My mechanic buddy that loaned me his snapon bore scope has a dim view on them.  His comment, "if you knew you were going to have to dump it in x years, would you change the oil?" I think this is overly pessimistic 'cause I'd think you'd do enough required maintenance to keep warranty in effect!

B- Any recommended JDM dealer/source?  I'm on US west coast, Oregon.

C- I'm seeing more 4th gen 2009-2014 engines now than 3rd gen 2003 - 2009.

    i) Can a 2009 → 2012 (EJ25, pre FB25) work w/ my harness/ECU 

or

   ii) Is the 2009 → 2012 EJ25 long block compatible with my earlier SOHC EJ25 heads.  I'll do head gaskets on any replacement so swapping heads if it will work w/ the long block and then fit in car.  

I kind of hate to dump the car.  The body is straight/no rust, have really new Toyo Observe on factory steel wheels and even newer Michelins in factory alloys.  Just put a radiator in 4 months ago...

Thanks for all your help!

 

Cheers,

Tom