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May have found my misfire problem...probablly not, help?


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30 replies to this topic

#1 upDUHcreek

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Posted 18 September 2012 - 03:56 PM

Ok, I have a 99 Forester with the SOHC 2.5 engine. I've had a misfire, and been using oil, so I replaced the PCV valve, but there was no change. While I had the hose to the pcv valve off, I noticed the plastic part on the other end of the hose, where it and another hose connect to the block was so dirty that it's probablly clogged. I'd like to replace that part, but I have no idea what it's called. Can someone please tell me what that part's called so I can get a new one installed ASAP? Also, it looks like it's going to be a fun job, are there any tips that can make this easier?

Thanks for any, and all help. Sorry I don't have a camera to take a pic of the part I'm asking about.
Charlie.

Edited by upDUHcreek, 06 October 2012 - 01:27 PM.


#2 ocei77

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Posted 18 September 2012 - 04:36 PM

Look Here:http://opposedforces...on_control_pcv/

Go back to root for entire series.


O.

#3 davebugs

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Posted 18 September 2012 - 05:11 PM

Ok, I have a 99 Forester with the SOHC 2.5 engine. I've had a misfire, and been using oil, so I replaced the PCV valve, but there was no change. While I had the hose to the pcv valve off, I noticed the plastic part on the other end of the hose, where it and another hose connect to the block was so dirty that it's probablly clogged. I'd like to replace that part, but I have no idea what it's called. Can someone please tell me what that part's called so I can get a new one installed ASAP? Also, it looks like it's going to be a fun job, are there any tips that can make this easier?

Thanks for any, and all help. Sorry I don't have a camera to take a pic of the part I'm asking about.
Charlie.



Those always seem to have buildup - and can be brittle from heat and age.

Won't hurt anything, but I'll be surprised if it helps your miss.

#4 Rooster2

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Posted 18 September 2012 - 08:51 PM

You might do well to take that part and soak it over night in a solvent, or even gasoline. Wipe it out real good with rags or paper towels to remove the gunk, and reinstall.

Like someone else said, I would be surprised if cleaning or replacing the part solves a misfire. I would be more inclined to replace the spark plugs and spark plug wires, if they are old.

#5 davebugs

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Posted 18 September 2012 - 09:53 PM

You might do well to take that part and soak it over night in a solvent, or even gasoline. Wipe it out real good with rags or paper towels to remove the gunk, and reinstall.

Like someone else said, I would be surprised if cleaning or replacing the part solves a misfire. I would be more inclined to replace the spark plugs and spark plug wires, if they are old.


Folks seriousely under estimate the importance of OEM (some say NGK too) plug wires on 2,5's (DOHC and SOHC).

Same goes for getting a fancy plug rather than what is called for. Bosch Platinums have caused more problems in more different cars that anything in recent memory other than Ethanol.

#6 Fairtax4me

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Posted 18 September 2012 - 10:32 PM

All of the PCV hoses can be cleaned with a bottle brush and some brake cleaner or throttle body cleaner. Chip the crud out, spray, brush, repeat until clean.

The large hose that attaches to the block may be difficult to remove, but usually doesn't clog so it probably doesn't need to be taken off. The Y section and hoses above it are easily removable by loosening the clamps (channel-lock pliers), and twisting and pulling them apart.

Agreed that misfire is probably spark plug related. All too common on the 2.5.

#7 Ricearu

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Posted 19 September 2012 - 11:53 AM

especially if the wires are aftermarket junk. Use dealer oem or ngk wires and ngk platinum plugs.

#8 upDUHcreek

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Posted 19 September 2012 - 11:56 AM

ocei77
Thank you for being the only one who was considerate enough to even try to answer my question.


To everyone else.
Of course the first thing I did was install OEM wires, and NGK plugs. I left that out in an effort to save you all some time reading, and save myself some time typing.

#9 Ricearu

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Posted 19 September 2012 - 12:11 PM

well, it happens so often that our records are all broken in that spot! ;)

I would check for intake and or vacuum leaks. Is it a specific cylinder or random misfire? Does it post any codes/check engine light and what are the codes?

My wife's old 98 forester posted a p0420 code and we kept driving it and within short order, it started bucking and surging under load. I chased my tail for weeks and realized it was the cat with an intake vacuum test. Under steady throttle at around 2k, the vacuum will fall off hard. I pulled the manifold and cat and found that it had melted down and over half was completely blocked and 25% was partially blocked.

:Flame::brow:

#10 upDUHcreek

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Posted 19 September 2012 - 12:33 PM

I'm almost convinced the O2 sensor, is my problem, but I'll probablly wind up changing all the cheep stuff first in an effort to avoid spendint the $200 the stealership wants for an O2 sensor. At least I know my cat's aren't backed up yet. One of the good things about having a buddy who owns a muffler shop is that he's so happy to see you he'll do minor stuff like that just to have someone to talk to about fishing while he's working.

Look guys, there's no need for EVERYONE to say plugs and wires. After a couple guys say it, the repetition starts to sound like everyone thinks you're dumber than dirt. I'm not trying to hurt anyone's feelings, I just thought you might want an honest opinion about how you're making others feel. I have to go buy some tools now, so I'm out of here. I know you were all just trying to help, so I'm not upset, and I hope my comment didn't upset any of you.

The guys I'm really pissed at are the guys on the local forum here. They hooked me up with a mechanic, who has NEVER returned any of my phone calls. After 4 months of trying to reach him, I gave up. Now I'm feeling more than a little abandoned. I have cash, but I could use some serious help with this car. It needs some repairs I'm too inexperianced to even diagnose, much less attempt to fix. Luckily I've learned a lot by spending an hour or two minimum each day on here, or NASIOC, or other subie sites over the last couple months. My major problem is that I'm handicapped, so there's some stuff I just can't do. It's hard to admit that, but you have to know your limitations, or you'll just wind up making things worse.


My original post was about twice as long as this one, but I edited it down, and wound up leaving out some stuff I should have included. I tend to ramble on. I guess that means I'm getting old. I must be getting towards my midlife crisis now, because I'm starting to wish I'd gotten a Fozzy with a turbo, instead of this normally aspirated one.

#11 Rooster2

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Posted 19 September 2012 - 12:34 PM

Folks seriousely under estimate the importance of OEM (some say NGK too) plug wires on 2,5's (DOHC and SOHC).

Same goes for getting a fancy plug rather than what is called for. Bosch Platinums have caused more problems in more different cars that anything in recent memory other than Ethanol.


Bosch Platinums are a matter of opinion. I have used them in 3 Subies, and two other cars for years with no issues. I use their single tip, not the ones with two or three tips.

#12 Ricearu

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Posted 19 September 2012 - 12:39 PM

Bosch Platinums are a matter of opinion. I have used them in 3 Subies, and two other cars for years with no issues. I use their single tip, not the ones with two or three tips.


balk! :horse: :D

I just love when I buy a car with a miss for a great price, and the electrode has receded into the insulator and no longer fires. Throw them in the trash.

#13 upDUHcreek

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Posted 19 September 2012 - 01:25 PM

Bosch Platinums are a matter of opinion. I have used them in 3 Subies, and two other cars for years with no issues. I use their single tip, not the ones with two or three tips.


Never had any luck with those. I tried them on two different cars, and they never lasted a month before they started to misfire. I've been a fan of NGK's for about 20 years now, I even use them on my remote controled 5th scale pictured below.


http://www.bajaaddic...8080552&thumb=1

Edited by upDUHcreek, 19 September 2012 - 01:51 PM.
added pic


#14 davebugs

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Posted 19 September 2012 - 02:10 PM

balk! :horse: :D

I just love when I buy a car with a miss for a great price, and the electrode has receded into the insulator and no longer fires. Throw them in the trash.


Me too. Subaru's in the past Volvo's, even VW's which often had Bosch (more normal plugs) as OEM.

I use NGK for everything but my 90's Chevy's.

I LOVE Bosch Platinums in that they let me buy cars cheap. I'd never install them.

YMMV

#15 Fairtax4me

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Posted 19 September 2012 - 02:14 PM

We can't know for sure what you've already done to the car in attempts to correct an issue. If you don't say that the plugs and wires have been replaced with NGK or O.E. parts that wil be the first thing people on this board recommend. The 2.5s are picky about spark plugs, and we see threads about spark plug related misfires all the time.

Help us to help you by including recent service work, year model and engine size, and when the concerning issue is likely to happen in the post. This way you don't get "spark plugs and wires" from every other person who posts a reply.

#16 unibrook

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Posted 27 September 2012 - 12:30 PM

Does it misfire right from start, when the car is cold?
Or only after the car is warmed up?

If only when warm, and your front 02 sensor has not been replaced in the last 40k miles......I vote to change it.


Worked for me. (2001 Forester 116k miles).......(now on its 3rd front 02 sensor, if u include the original)

:popcorn:

Edited by unibrook, 28 September 2012 - 07:50 AM.


#17 ocei77

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Posted 27 September 2012 - 08:26 PM

[QUOTE.....to avoid spending the $200 the stealership wants for an O2 sensor. ......[/QUOTE]

If you decide to go for an O2, go to RockAuto or other vendor, buy either Denso or Bosch , $50-60.

O.

#18 upDUHcreek

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Posted 06 October 2012 - 01:26 PM

Sorry it took so long to reply.

Unibrook
I'm pretty shure it misfires from the start. You can't really feel it untill the car's been running for about 15 seconds, and the idle's droppd down to about 1K RPMs. The CEL only takes about 5 seconds to start flashing.

OK guys, you want info, this is all of it that I can remember. I'll wait for some more input from you guys before I order more parts. I just don't know what I'm doing, and I apriciate any input from people with more knowlage than I have.

I bought this 99 Forester with 2.5 sohc engine almost 14 months ago. It had a misfire then, but no CEL at the time. After about a month, I got the dredded 420 code for catalitic converter inefficiency, CEL was intermittent, but always 420 code. At that time, I changed plugs and wires, with E3 plugs and crappy wires; no change. After that I started to spend time researching here. Next weekend I swapped the plugs and wires for all NGK since some people reported the ngk wires also work well, and they were $20 cheeper than oem. No immediate change, but a couple weeks later I got my first misfire on #1 code, no noticable difference in how the car ran.

Then the weather turned colder, and I noticed some smoke from the exaust on cold startup that went away once the engine got halfway up the gauge to operating temp. It only smoked when temp was below 50, and when it was the first startup of the day. There was no noticable difference in how the car ran.

Next problem, head gasket failure due to me racing a vette in the rain. Sorry, I just couldn't resist seeing the look on his face when I dusted him good. Decided to flush the system, I put 2 cans of Subie "coolant conditioner" in, and changed the oil, just to make shure there wasn't any water in it. Since then(9 months), I've only had to add about half a gallon of antifreeze, but I keep a close eye on the level, just in case. It only took 2 days for me to take care of this, so I'm pretty shure I got to it before serious bottom end damage happened. I kept antifreeze in it, and it never overheated.

Weather warmed up, morning smoking issue went away and we went back to work on it. I tried changing NGK wires for OEM, no change. Performed the "spray bottle" test on the coil, no sparks. Tried the dollar bill over the exaust test, it didn't try to suck the bill back into the tailpipe. At this point, I decided to purchase my own OBD2 reader, mostly because I was getting embarrased from my frequent trips to have the parts store guys read the code for me. That was probablly a mistake, the code reader gave me too much info that I just didn't understand, which only confused me more. I thought my car had a MAF sensor, but it says MAP on the data stream.

Here's the numbers from the snapshot from the live data stream.

fuel sys 1 CL
fuel sys 2 NA
Calc Load(%) 21.2
ECT(F) 194
STFT B1(%) 7.8
LTFT B1 (%) -3.1
MAP (inHg) 18.6
Eng RPM 2125
Veh Speed(mph) 20

I just thought I'd add that fuel sys 1 changes to open loop when stopped at lights or stop signs.

Just to see what happend, I cleared the codes, and the CEL was back on and flashing right at about the 2 mile mark. Then I really got confused, because intead of misfire #1, it was #2, with no misfire code for #1, but no 420 yet. I decided to give it a rest, to keep myself from pulling out what's left of my hair.

Summer got here, and it got hot. After about a week of running the AC, misfire got worse. Hooked up the scanner, and it says 420 with misfires on #2 & #3, but still no code for #1. Car had very little power with AC on. It did OK on city streets, but almost no acceleration above 50mph, unless I turned off the AC untill I got up to speed, or floor it.

Now at this point, it's been weeks since the last time I worked on the car, and I'm leaving a friend's house to head home in the rain. No CEL at all, and the car's even running smooth at idle. After a short drive to the hiway(slightly over 1/2 mile with 3 stoplights) car's got much more power, and pulls on the hiway like nothing's wrong at all (65mph at the end of the onramp without hitting 4k rpms). That's NOT the first time it's rained, but it's the first time the CEL has ever gone completely out. Once or twice before(always in the rain), it did stop flashing, but only for a few seconds at a time. That's also the first time it's had that much power. 3 miles down the hiway, and the CEL's flashing again, and things are back like they were.

Two weeks ago today, we replaced PCV vlave, fuel filter, and plugs. The #2 plug (front driver's side) was covered with black oily residue. Car's got more power, but is still missing, also power sometimes seems to come and go. It's similar to the surges in power when the AC is cycling on and off, but my AC's not on. On the hiway, the CEL will frequently quit flashing for a few miles, but is still always on. I also bought some MAF cleaner, but we didn't have the special allen tool needed to remove the MAF to clean or replace it, so I put it off for now. Anyone know where to get that tool?

Last time I went to the auto parts store, Lucas fuel treatment was on sale, so I picked up 3 bottles for $14. One bottle is in the tank right now, and I intend to use the other two in my next two tanks of fuel.

The more I think about this, and the more I read here, the less I think it might be my O2 sensor, mostly because the misfire doesn't wait till the car's up to temp to start. As I stated before I'm hoping to get much better info before I start throwing more $$$ at parts trying to fix it. I'm hoping someone will see something in the snapshot from my code reader that will pinpoint the problem. I know what most the parameters are, but I have no idea if the values are in line, or way off base.

Thank you all for any help.
Charlie

Edited by upDUHcreek, 06 October 2012 - 01:36 PM.


#19 Fairtax4me

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Posted 06 October 2012 - 02:00 PM

Some cars had no MAP, some cars had no MAF, but the info sill displays in the freeze frame data. The ECU still uses the info but it uses input from other sensors to calculate the reading rather than using a MAP or MAF sensor.

I'm kind of wondering if the timing is out after reading through your history of the problem. But I'm thinking it could also be due to a compression issue and/or oil fouling from bad rings or even damaged valves. A dead misfire will foul plugs with oil/fuel residue in a short time though.

But this part

I just thought I'd add that fuel sys 1 changes to open loop when stopped at lights or stop signs.

makes absolutely no sense. OL and CL operation depend on O2 sensor temperature, engine temperature, and throttle input. The primary factor in changing from OL to CL is when the 02 sensors get hot enough to start sending a signal to the ECU.
Wide Open Throttle will switch the system back to OL.

I don't see any mention of the knock sensor here. Has that ever been checked/replaced?

#20 upDUHcreek

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Posted 06 October 2012 - 02:08 PM

Not yet. The knock sensor is next on my list of things to change. I started with the cheepest stuff first, and I'm working my way up to the more expencive items since I still have no clue.

It's been months since the gas pedal's been incontact with the floor. Generally I try to use as little throttle as possible to save gas.

Then again, I could be remembering it wrong, it's been quite a while since I've looked at the live data stream.

Edited by upDUHcreek, 06 October 2012 - 02:17 PM.


#21 Fairtax4me

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Posted 06 October 2012 - 02:17 PM

New knock sensors are less than $20 shipped on eBay.

#22 upDUHcreek

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Posted 06 October 2012 - 02:55 PM

Sorry, but I don't do ebay. I don't even have a paypal account. I'm really not quite old enough to be this paranoid, or pesamistic, but I think of it as being cautious. As cheep as I am, you think I'd never buy stuff from any place other than ebay, just because you can find stuff there so cheep. I just don't feel I can trust people I don't know, or companies I've never heard of with my money.

Then again, I've been known to spend $100 when I only needed a $7 item, just to get the free shipping. I'm one messed up cookie, but thanks for trying to help. I'll probablly just order it from Rock Auto, or the local parts store, if I decide I don't want to wait on it.

Charlie

PS I think I'm going to go play with the live feed on my scanner again. I want to make shure that I remembered that bit correctly about it going into Open loop when the car was stopped and in gear.

Edited by upDUHcreek, 06 October 2012 - 02:59 PM.


#23 upDUHcreek

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Posted 06 October 2012 - 05:41 PM

I was wrong. The live feed says OL-drive as soon as I let completely off the gas, then it switches back to CL when the car's slowed down almost to a stop. Also, it switches to OL-drive when the throttle position reads over 30%.

Voltages on the front O2 sensor ranged from 0.0(coasting), to 9.25(WOT), that's the highest I saw on the front one. Front sensor seemed to vary much more than the rear one under steady throttle input.

The live feed shows many more sensors than the snapshot saves. If there are any questions about other sensor values, I'll will be happy to make another run and get the values for the other sensors too.

Thank you for your help
Charlie

#24 upDUHcreek

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Posted 06 October 2012 - 08:53 PM

And now the plot thickens. After driving it like I stole it to monitor the O2 levels, and the fuel sys 1 readings at WOT, I decided to clear the codes while I had the scantool connected. CELight stayed out for about a quarter mile at 25 mph before it started flashing, and the misfire #2 code returned. I continued to my friends house to hang out for the evening, and that's where I was when I made my last post. When I drove home, just a few minutes ago, it happend again, but this time it's NOT raining. No CEL at all, and no shaking from any misfire. Drove 6 or 7 miles down the hiway, still no CEL at all. Pulled off the hiway, and I could feel it missing a little at the light. Pulled up to the next light on the other side of the hiway, and the CEL starts flashing again. It's still missing, but no where near as bad as before we changed the plugs, fuel filter, and the PCV valve 2 weeks ago. Is it possible that I just need to run some seafoam through it? Could it be that simple?

This really has me all messed up. Every car I've ever owned has had a problem at one point or another that disapeared when I took it to the shop to have it looked at. Life can really be strange sometimes.

Thanks for any input guys.
Charlie

Edited by upDUHcreek, 06 October 2012 - 08:56 PM.


#25 Caboobaroo

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Posted 07 October 2012 - 11:21 AM

Sounds like you need to start checking a few other things. On a misfire situation that seems to come on right away, firstly I would check spark and fuel. Since you have already replaced most of the parts in the secondary ignition system, I would swap the fuel injectors between #2 and #4. If the issue follows to #4, then it's most likely a bad fuel injector.

Another easy thing to check are the valve guides. It is a common issue where the valve guides start moving in the head and slowly shifting out toward the head of the valve. All you need to do is unbolt the exhaust manifold from the bottom of the heads, grab a flashlight and start looking up into the exhaust ports on the heads. The guides should be only showing about 1/4" but when they shift far enough out, it can actually hold the exhaust valve open and give you a misfire.

If the guides look good, then I would do a compression test and/or leak down test. There is also a possibility that you have an exhaust valve burnt that is causing the misfire which can cause low compression and/or 100% leak down.




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