Greetings Scoob experts,

 

I have developed a misfire and am struggling to get a handle on what the issue is. Here's some background:

The misfire is only really apparent when the car is idling and you can hear/see the engine stumble slightly, not a a lot, bu it's there. Every now and then a check engine light will be thrown with a 0301 code. As the plugs and ignition leads were due a change, they got changed. No difference. The coil pack got changed: no difference. I tested the spark of that cylinder against the block when running: they all appeared consistent in timing and strength. I did a compression test: all the cylinders came up the same strength and healthy (the head gasket and all seal had all been recently changed). So now moving onto the fuel system, I figured that by swapping two injectors I could determine it would be the culprit if the code shifted from 0301 to 0303 (i swapped cylinder 1 and 3 over). The problem is that the issue is so weak that the CEL won't activate to determine it. 

Any advice?

 

Thanks in advance. 

Crank position sensor can cause misfires. An internally shorted sensor like an O2 (even a shorted heating element can do this) can cause misfires as well, though I'd expect it to be a random misfire vs. specific.

 

Also, check the wiring going to the coil. If you see ANY exposed wire through the rubber, fix as needed. Anything from chaffing, heat, rodents, etc. can cause problems.

 

Are you getting ANY other codes at all? Even ones pointing to something else?

 

And has it actually thrown a misfire code since you swapped the coil pack? My '95 seems to like idling around 650 rpm, and has a slightly wonky idle, like an older inline 4 cylinder you'd find in say a late 80's Ford Ranger or similar vs. a newer engine where you can barely tell it's running at idle.

Edited April 1, 20187 yr by Bushwick

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The MAGICAL MISFIRE TOUR< IS COMING TO TAKE YOU AWAY< TAKE YOU AWAY !!! 

 

 

Seriously.....do a compression test.  probably a valve

Edited April 1, 20187 yr by Gloyale

Seriously.....do a compression test.  probably a valve

 

He did

All the wires appear to be in good shape - nothing exposed etc. Both o2 sensors have recently been changed for OEM replacements. Also this is the only code thats being thrown (0301) so I would probably shy away from it being the crackcase sensor due to it being specific and no code 0335, or maybe im wrong. Also yes, the code has come up since replacing the coil pack.

Edited April 1, 20187 yr by jonesyb84

not sure where it would lead you but, wonder if a little spray of starter fluid, or even a little propane from an un-lit handheld torch would make the engine smooth-out at idle? or, get worse?

 

problem with fuel regulator or damper??????

Edited April 1, 20187 yr by 1 Lucky Texan

not sure where it would lead you but, wonder if a little spray of starter fluid, or even a little propane from an un-lit handheld torch would make the engine smooth-out at idle? or, get worse?

 

problem with fuel regulator or damper??????

 

My initial thought at the moment is the injector - hence swapping them over. I guess as a driveway mechanic its a little frustrating to waiting for the CEL to come on to confirm if that is indeed the issue. Although my motor would probably love a new set of Injectors, it's not getting them unless thats the issue!

Edited April 1, 20187 yr by jonesyb84

ELM327 BT adapter device with an app like Torque running on a smartphone would get you live data - post it and one of the gurus here may spot something helpful.

 

those adapters aren't expensive.

Year? Engine? Mileage?

 

You just replaced the head gaskets?

Year? Engine? Mileage?

 

You just replaced the head gaskets?

 

2007 2.5i 150,000

 

Head gaskets replaced 2,000 miles ago

Edited April 1, 20187 yr by jonesyb84

ELM327 BT adapter device with an app like Torque running on a smartphone would get you live data - post it and one of the gurus here may spot something helpful.

 

those adapters aren't expensive.

 

Is there a device similar for Apple products, or are these limited to android?

Make sure timing marks are lined up correctly.

Check valve lash, then do a leak down test to rule out a valve problem.

 

Is there a device similar for Apple products, or are these limited to android?

 dig around on Amazon, pretty sure there's BT and wi-fi devices for iphones too.

What brand of spark plugs did you use?

 

(NGK are the ONLY ones to use in Subarus)

What brand of spark plugs did you use?

 

(NGK are the ONLY ones to use in Subarus)

NGK iridium 

The iridium ain't necessary--just plain old copper!

The iridium ain't necessary--just plain old copper!

 

Would that be detrimental though?

Probably not, just a waste of money.

What brand of spark plugs did you use?

 

(NGK are the ONLY ones to use in Subarus)

 

 

NGK iridium 

 

what kind of wires is the next question...

 

NGK or OEM only... store brands have proven time and again to be problematic.

 

as for the iridium plugs - meh - if it were me, they would get swapped out for the plain old copper core NGKs - just because...

Duralast Gold wireset is in place....I also ordered an ELM327 BT to see whats going on. I'll post the results in good time

As heartless said, only NGK or OEM wires are acceptable.  Off the rack parts store wires are inferior--no matter how fancy the name!

Duralast Gold wireset is in place....I also ordered an ELM327 BT to see whats going on. I'll post the results in good time

 

Replace with either NGK brand or OEM.

 

The last time I bought wires that were not NGK*, it was a set of Duralast wires on my 89 GL wagon (may moons ago) - they failed on me when I was 2.5 hrs from home. I swore never, ever again. (* never have purchased OEM wires - nearest dealer is too far away)

 

Failure was arcing through the plug boot to the engine block - it was so bad it was even obvious in bright daylight. Took seconds to find after getting off the highway to a safe place and popping the hood.

 

Managed to limp home by wrapping the crap out of it with electrical tape, but as soon as I got home a set of NGKs were ordered and I have never looked back.

 

I don't care how good others claim their wires are - on any of my Subarus it is NGK, period.

I second Heartless' statement. I've had Beldon (Napa), BWD (Borg Warner), ID, (Import Direct), all fail on me, in multiple cars.

 

NGK is the only aftermarket (which is the OEM manufacturer for Subaru) that has ever lasted.

So I second it being a possible wire problem.

 

Twitch

Im just waiting for an ELM327 BT to be delivered, then i can post the results to see if any of you guys can shed some light on the situation. Im reluctant to think its the cables as I swapped the old ones out with new plugs to try to remedy the issue which was there before - and there was no change. 

Edited April 12, 20187 yr by jonesyb84

here are some results from the ELM327 test i just ran:

www.weageomaha.com/1.jpg

www.weageomaha.com/2.jpg

www.weageomaha.com/3.jpg

www.weageomaha.com/4.jpg

www.weageomaha.com/5.jpg

www.weageomaha.com/6.jpg
www.weageomaha.com/7.jpg

If any of you guys could shed some light, that would be ace! Thanks!