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Old 10-16-2019, 12:35 PM   #1
Gamil
Scooby Newbie
 
Member#: 220375
Join Date: Aug 2009
Chapter/Region: TXIC
Location: Pasadena, TX
Vehicle:
2011 Outback Sport
Blue

Default #2 Misfire after rebuild, 2011 OBS

Had to rebuilt an EJ253 due to rod knock. Got it all back together and I'm having misfires on cylinder #2, P0302. Always the same cylinder. List of work:

Machine Shop:
- Cleaned all aprts
- checked clearances/sizes of crank, pistons, cylinders etc
- Valve job
- Assembled valves+springs into heads with new OEM springs

My work:
- Disassemble everything except valves+springs , drop off at machine shop
- reassembled everything except valves+springs, with all new bolts, OEM gasket/seal kit
- followed FSM religiously
- Chopped heat sheilds off OEM exhaust headers because harmonic death rattle. Applied DEI Titanium Exhaust wrap.


"Upgrades"
- Delta Cams, 1000 grind
- ACT XACT StreetLite LW Flywheel (ACT600705)
- Exedy Stage 1 Organic Clutch disk (EXE15801)
- King Race Bearings
- STI Rods (pulled from "new" STI getting prepped by race shop)
- New Spark Plugs, NGK Iridium IX
- New Plug Wires, Duralast "Gold" (do plug wires make any difference?)
- New OEM Knock Sensor and wiring harness b/c I'm a clutz
- "Group N" Mounts (D1010FE020, D1010FE110, D1010FE120)


From my forum readings, there's a good chance of a "phantom" misfire due to either the cams or the LWFW, and combined it's pretty much guaranteed. But, there have been a few times where I've felt a misfire. Or, rather, RPMs dropped for seemingly no reason. Idle with all electronics off (radio, headlights, fan, AC) is pretty stable, but if I turn on ventilation, then sometimes as the radiator fan kicks on/off, the RPMs drop low, and stall on rare occasion.

This weekend, I drove it to an autocross, had cruise control on the whole ride, no hiccups. Once I arrived in paddock, let the car Idle while I put air in the tires, and that's when revs dropped out and code pops up. After that, ran smooth rest of the event and all the way home.

I reset the code yesterday, and then last night, again, P0302 pops up while I'm sitting at a light, but the revs didn't drop this time.

There have been a couple times that I noticed the engine lugging/bucking around 2500rpm under light acceleration, and shortly after while idling the code popped up.

Compression test: 195±5psi on all cylinders
Swapped Fuel Injectors between #2 and #4. No change

After work today I'm planning to Gap the spark plugs, and tomorrow I'll check the valve lash (reaaaaly, don't want to have to fix that with the engine in the car. Was annoying enough with the heads on a workbendth)

EDIT: ***Troubleshooting Summary to date***

- Compression test: 195±5psi on all cylinders
- Swapped Fuel Injectors between #2 and #4
- checked plugs:
--- #2 is sooty
--- the rest are A-OK
--- Gaps are good
- Swapped plugs
- Swapped plug wires between 2/4
- Swapped coil pack connection point between 1 & 2 (b/c wasted spark)
- Tested Coil pack resistances: almost bang on spec, well within tolerance)
- Tested plug wire resistances: Only #4 was out of spec, low
- Checked valve Lash
--- found and corrected +0.003" on secondary intake ie the variable one, noticable decrease in valve noise.
- Timing checks out, with both the pulley marks and what's left of the lines on the belt.
- Replaced the broken ground strap, no change

Last edited by Gamil; 11-10-2019 at 03:35 PM. Reason: consolidating Troubleshooting to OP
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