hello wrxatl! have a slight issue with misfires on cylinder 1 and 3. I have had the car for almost 3 years now and besides a o2 sensor code this is the first time ive seen the CEL come on. Since i bought the car i always thought it had somewhat of a rough idle causing the whole car to shake. After tons of research, ive come to the conclusion its a subaru thing. So i ignored it and the car has been running just fine. Well today i was on my way home from work and i felt like the boost wasnt coming on as fast. I didnt think much of it but as i was making a turn at low speed in second gear (probably should have been in first gear) the car stumbled a bit and my check engine light came on. no blinking cel just a solid light with blinking cruise light. car actually seemed to drive fine all the way home although i stayed out of boost. codes are p0303 and p0301. idle seems a little low and when i turn the lights on or the blower motor the idle bumps up and idle is smooth. plugs are only a year old and i did a timing belt job last year. also noticed the exhaust pops but i didnt think much of it. i also just filled up the tank today with 93. im going to dig more into tomorrow i just wanted to see what you guys thought. thank you!
I recently had to track down some misfires on a used subie I picked up. I found this thread to be the most helpful:Misfires I was getting a "cam sensor position bank 2" CEL and some misfires on all 4 cylinders. In my case a post MAF leak was the culprit. GL
i was actually just reading a thread on nasioc about a valve cover leaking into the spark plug holes. i literally bought a valve cover gasket, half moon seals, and spark plug gaskets yesterday at subaru because my right side cover is leaking. so im going to tackle that first.
Well there's no oil in my spark plug holes. Spark plugs look fine. When I loosened the bolts to the valve cover it sounded like air pressure was released. Is this normal?
How many miles are on the plugs? I see you did them a year ago but mileage can vary greatly.. Also swap the coil packs front to rear and see if the misfire moves..
the plugs are just oem replacements. ngks. i havent started the car after doing the valve cover gasket. i broke the purge valve solenoid while installing a turbo inlet. replacing it tomorrow though (stupid $100 mistake). i also cleaned all the nasty milky water/oil mixture from the breather hoses. along with replacing purge valve tomorrow, im checking my grounds and cleaning up the surfaces.
Try moving the coil packs and see if the misfire moves to the other side of the motor. Then repeat the same thing for the injectors, or better yet pull the injectors and have them cleaned.
Check all common sense/ free/ common areas before wasting money. Inspect all battery cables especially the grounds on the motor. Corrosion will cause problems. (Hondas are notorious for no start conditions for a bad ground that goes from valve cover to the rad support.) Check all hoses for cracks and leaks (especially breather hose and i/c coupler) Check air filter Inspect gap on plugs. Check your manual but IIRC It's 29 gap. someone please correct me on this. Clear check engine light. swap coils with the other bank. if light comes on p0302 or p0304 you know coils are weak. If 303 and 301 still appear, move on. Clear CEL. swap injectors to other bank. Inspect and clean before doing so. Same codes above should appear for diagnosis result. Clean both your MAF/IAT sensors (two sensors in one part) with $3 can brake parts cleaner. Since you bought that brake cleaner might as well unplug your 02's and grab a wire brush and clean them. Got a high mileage motor? Valve adjustment will fix a lot of cold start idle and take off. Not a power adder just something you notice & feel here. This has to be done on a cold motor. I personally prefer to do mine a little on the tighter side. Have fun doing it in the engine bay..... Have basic tools, time, and are mechanically inclined? Check and inspect ALL CMP and CKP sensors as well and engine base timing. Still missing. Start spending money on deposits on special tools- compression tester, cylinder leak down tester, block tester (possible hg going out) This normally solves most misfire problems from my experiences. When in doubt KISS it - Keep It Simple Stupid. Never become a part swapper or get into that bad habit. Before I hurt my back and ran my shop I made much more money on diagnostics than actual repairs. A lot of cars both stock and modded have problems that are because of dirt and age and wear. Parts don't always have to be changed. They can be cleaned and readjusted most times.
finished the evap purge solenoid and replaced a few more hoses. cleaned up a couple grounds then cleared the light. drove the car a couple miles down the road and back. everything seems fine. checked out the live data on the accessport. no feedback knock or cylinder roughness. i have a 15 mile drive to work tomorrow so well see how she does then.
well just got back from work and everything is still fine. checked the acessport for feedback knock which is 0 and cylinder roughness which is also 0. but i watched knock sum and it had a count of 30? please help me understand this haha.
What timeframe and distance did you accumulate that over? Some knock sum can be caused by noise. If you got 30 during a short pull that is really bad. If you got 30 over say a commute of 25 miles home that's different. Hopefully somebody with more experience can confirm.
oh it was 30 over ten miles or so just highway cruising. im thinking bad gas is the issue here to begin with. i filled up the same day as the misfire. we just had all that snow and im thinking maybe water got in the tanks.
if you have a scan tool and can do live data stream & freeze frame it can help you know exactly what is going on
ok so everything has been fine and dandy until today. no cel BUT i did feel the stumble/hesitation again today. just so happens that i was also low on fuel (no gas light on but still low). so i filled up on 93 at a different gas station than the first time. car felt weird almost like the motor was struggling or starving. only happens between 2400 to 3000 (give or take) rpms but once i get on it more or its in boost it pulls great and feels fine. so im starting to think maybe its a fuel issue. things ive done so far: right side valve cover gasket, checked plugs and they look normal, replaced turbo inlet because the oem one was soft due to oil sitting in it (i could almost fold it in half), cleaned all breather hoses and pcv valve, installed moroso air/oil separator, oil change, replaced coolant hoses and radiator (was going to anyway), put lucus fuel system cleaner in tank, reflashed stage 2 with the current update, cleaned mass air fow sensor, replaced k&n with brand new oem filter. again after all this the car ran GREAT until i got low on fuel.
ok so i have a log i need to have someone look at. i sort of know what to look at and what numbers mean what but im positive there is someone on wrxatl that would be able to help me. oh by the way, please dont pay attention to my miss shift. im not real sure what happened but i missed 4th and it scared me haha. motor actually seemed to take the abuse like a champ though. https://docs.google.com/spreadsheet...-L0eopTZzo/pubhtml?gid=1375990265&single=true
well im not sure if anyone is still reading this or not. I think I have found the issue. Ever since i got the car when you turn the key you can hear the fuel pump sucking in (what it sounds like) air. Or maybe its the sound of it struggling to push fuel through. well today I pulled my fuel pump and found a few things that concern me. looks to me like the previous owner spent some time off-road. let me know what yall think!
welllllllll new pump and filter installed and runs great. except after maybe a day the cylinder 4 misfire code popped back up. once again i didnt feel any sort of misfire. cleared the code and yesterday night and so far no code has popped back up. i had a friend at work use his scan tool to read some numbers and a few numbers he told me to check on were: A/F Current #1 - .00 - at idle - 2500 RPM - -.12 -resistance- 31 ohms A/F #3 Correction - -0.31- at idle A/F learn - 1.6 - at idle not 100% sure what exactly these numbers mean. tech at work says im running rich. Im really just trying to get an idea on where to start diagnosing. Things I know so far: MAF reading correctly and is clean. Fuel pump and filter brand new. Spark plugs are fine and within spec. Grounds are clean and secure. No off-sounding noises. Did a lot of research and the only thing I found close to my situation is a guy who owns an sti swapped gc8 is getting misfire codes and not feeling misfires was because of a neutral position switch. Not real sure how thats related and it was never explained in the thread i read. I have diagnosed misfires before but nothing like this. Im getting air, fuel, spark. Now why im getting random misfires that im not feeling is out of my skill set haha.
Thats a little on the rich side but you should be ok. Plug up that afr gauge, calibrate your fpr, and retune.
Alright thank you. I'll def be calling mr. Doug here soon for a tune. Also I lnow I said the grounds are good but I notived I don't have any ground straps on the bottom of the motor . Am I supposed to have them?
I've never noticed but I dont think you have one there. You should have 2 on the intake, 1 on the battery, and 1 on your tranny. Someone please chime in and verify. Wouldn't be a bad idea to make a grounding kit. ;D
one on the pass head to the fender well. Its a snap in spade connector. Dual AVCS have straps on the lower part of the head
can someone maybe post a picture of what its supposed to look like? i know i dont have any grounds on the bottom of the motor at all. have a tune scheduled with doug in a couple weeks btw! stoked to check out his shop.
that picture is gigantic brian hhaha. we had a completely stock 2006 sti come into work today and there are no ground straps on the bottom of the sti motor. what year car is that that you took a picture of? i made a couple ground wires anyway to try but im not sure if it would even make that much of a difference.
well car has been running great this past week and a half. i was so confident that i scheduled a tune with mr doug next weekend. until yesterday... cylinder 4 misfire again. same symptoms as the other times. as soon as the clutch is released from 1 to second, just normal driving. i havent gotten the cylinders 1 and 3 misfire ever since i did the valve cover gasket and cleaned all the milky, oily substance out. now i have had cylinder 4 code three times. a little bit of a rough idle but drives great in higher rpms. i just did a quick compression test on cylinder 4 and i got 143 psi. which is good news. actually when i went to take the plug out, it required almost not effort to loosen it. which could have been my issue. im putting it back together tomorrow and making sure the plug is tighter. also ill be switching coil packs just so i can rule that out. I dont know how to do a leakdown test nor do I have a tester. I read on a bunch of forums that just because the compression is ok doesnt completely rule out my misfire not being a burnt valve or something. So ill be looking into getting that test done this week. Im in the canton area if anyone wants to drink a couple beers and show me how to do it haha. I also wanted to bring up that my boost gauge (which i know is not that accurate) fluctuates boost at idle but its never more than 3 psi. Its constantly going up and down 1 psi at idle though. I appreciate you guys helping me out!