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Old 09-27-2018, 12:30 AM   #1
Stevenjr93
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Default 2002 Impreza outback sport 2.5l H4

Looking for some support/advice on some issues im having with my new to me impreza. This is my first subaru, so some of these things may be normal with these cars but im not sure.

Firstly; the transmission/clutch. I changed the tranny fluid which was very black to Royal Purple 75w90, and it shifts ok except for a few things.

1) Going into first at a stop sometimes grinds; which i understand is pretty normal and is solved by going into second, then first.

2) Occasionally when shifting I feel/hear a clunk that seems to be coming from the engine bay right in front of me. Sounds almost like its on the firewall, or perhaps engine mounts?

3) My clutch pedal feels very odd. When I first start driving, the engagement point is very low, and at the bottom is feels almost like its grinding/scraping at a pivot point. The top quarter of the pedal seems to be loose. As I drive the engagement point gets even lower, to the point where full compression feels like its barely disengaging the clutch, and the top 3/4 of the pedal literally does nothing; almost as if it is totally detatched from any return spring it moves so freely, but does stay mostly at the top when i let go. Is this air in my hydraulic system or something else?


Second problem is my CEL P0402; the o2/cat code. I tried the $5 fix with the non foulers, didn't work for my car. I wanted to get some UEL headers and a catback in the future; so should I just go ahead and do that and live with the light? I can't see any way around this browsing through old threads if I want an aftermarket exhaust anyways. Also, is it possible to leave the mid pipe and just get the catback and headers? Or do I need the full system at that point?

Lastly, my car seems to have issues filling; so that points to the evap system. After some research it seemed to be the charcoal canister, so I removed it and inspected it. Weighed 4.5lbs (normal?) and no sign of any pellets, the inside looked in pretty good condition from what I could see. I blew air through each inlet and some air did escape the other ports, but not 100% I would guess. Hoses seemed clear; is there as easy way to test the valves in the evap system?

Any help would be so helpful, I love this car so far but i need to fix these gremlins.
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Old 09-27-2018, 02:04 PM   #2
yarrgh
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Join Date: Jan 2005
Chapter/Region: RMIC
Location: Bailey, CO
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2001 2.5RS
Black Diamond Pearl

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1. This year transmission shares fluid with the front diff as well as synchros, so you need gear oil that can accommodate both. I don't know if royal purple is better for high pressure (front diff) or yellow metals (synchros). Maybe it's ok for both.

2. It is a 2002, rubber bushings do degrade over time. You say "when shifting", does that mean clutch in, moving the lever, clutch out? Check the pitch stop to see if it's healthy/bolted in tightly.

3. You can adjust the clutch engagement point. It's a 12mm nut under the dash and a threaded rod. I've had an issue where as the clutch master cylinder got hot, it wouldn't work as well. Replacing it fixed that issue. You can certainly bleed it as a quicker/cheaper fix to see if that works. Note that the clutch fork on these cars have been known to die after a while. Sometimes they bend, crack, or even wear through at the pivot point.

4. Do you mean P0420? You gotta be crystal clear when communicating problems through text. A catback exhaust won't have any effect on car efficiency or that code. Some say that headers don't hold heat as well, which leads to cooler gasses entering the cat, which would affect cat efficiency. I've had a vacuum leak lead to a 420 code before, so you might try checking for that as well first. For me, the cruise control vacuum source didn't have a clamp (do any of them?) so that old/hard hose sometimes slipped off. 1 small hose clamp later (and one on the FPR) and things are fine.

Filling issues don't necessarily point to the charcoal can. It could be a valve in that area. You can connect the green connectors under the dash (to engage diagnostic mode) turn the key to on/engine off, and the ECU will cycle all the valves in the car. You can then get back there to see if the vent valve is working, I forget which one it is. It might need a simple cleaning. I've had to do that to the purge valve under the intake manifold before, sprayed some carb cleaner through it and it works now.
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Old 09-27-2018, 08:21 PM   #3
Stevenjr93
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Quote:
Originally Posted by yarrgh View Post
1. This year transmission shares fluid with the front diff as well as synchros, so you need gear oil that can accommodate both. I don't know if royal purple is better for high pressure (front diff) or yellow metals (synchros). Maybe it's ok for both.

I think I'm going to swap both front and back to Motul300 for ease of mind, and to rule out the fluid in any issues that I still feel.

2. It is a 2002, rubber bushings do degrade over time. You say "when shifting", does that mean clutch in, moving the lever, clutch out? Check the pitch stop to see if it's healthy/bolted in tightly.

Yeah occasionally when i release the clutch it will clunk, it almost sounds like movement so I guess ill hunt around and change out bushings that need it.

3. You can adjust the clutch engagement point. It's a 12mm nut under the dash and a threaded rod. I've had an issue where as the clutch master cylinder got hot, it wouldn't work as well. Replacing it fixed that issue. You can certainly bleed it as a quicker/cheaper fix to see if that works. Note that the clutch fork on these cars have been known to die after a while. Sometimes they bend, crack, or even wear through at the pivot point.

Noted about the clutch forks. I will try bleeding and adjusting, if that doesnt work I'll try and test the master and see if maybe its leaking?

4. Do you mean P0420? You gotta be crystal clear when communicating problems through text. A catback exhaust won't have any effect on car efficiency or that code. Some say that headers don't hold heat as well, which leads to cooler gasses entering the cat, which would affect cat efficiency. I've had a vacuum leak lead to a 420 code before, so you might try checking for that as well first. For me, the cruise control vacuum source didn't have a clamp (do any of them?) so that old/hard hose sometimes slipped off. 1 small hose clamp later (and one on the FPR) and things are fine.

Yes, sorry typo. I will check for vacuum leaks and the condition of hoses. The car has 226k on it, so that's why I assumed the 420 code pointed to worn out/clogged cats; and rather than spending like 1k replacing them I'd rather just go aftermarket and get the sound I want.

Filling issues don't necessarily point to the charcoal can. It could be a valve in that area. You can connect the green connectors under the dash (to engage diagnostic mode) turn the key to on/engine off, and the ECU will cycle all the valves in the car. You can then get back there to see if the vent valve is working, I forget which one it is. It might need a simple cleaning. I've had to do that to the purge valve under the intake manifold before, sprayed some carb cleaner through it and it works now.

How would I go about testing the vent valve? I will try this on the weekend!
See bolded!
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Old 09-28-2018, 01:43 PM   #4
yarrgh
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Black Diamond Pearl

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You can also look at the rear diff bushings as they can move enough to create a clunking sound upon clutch engagement. You can use 3M window-weld to fill in the spaces (as opposed to new stiffer bushings).
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Old 10-01-2018, 05:52 PM   #5
CBDslappy
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let us know when you figure all this out. similar probs over here
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Old 10-02-2018, 03:19 PM   #6
02SportWagon
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-For your front diff/transmission, I highly recommend Subaru Extra-S, which is now called "Subaru High Performance Gear Oil". I run it in my 02 WRX and it helped with a lot of transmission/differential noise and hard shifts. Flat Irons Tuning has it on sale.

-For the clunks, its most likely your transmission mount bushing worn out and your pitch stop aka "dog bone" that attaches your engine to the fire wall is working to fight that. If the valve covers are leaking, I would bet that your engine mounts are toast as well. Group N engine and trans mounts helps with that as they're a bit stiffer rubber. I would recommend their dog bone as well.

-As for clutch pedal feel. I would inspect the whole assembly and system. I've got the whole adjustment and spec sheet. PM me your email and I can shoot it to you.

-P0402? I've heard of P0420, which is Cat Inefficiency Below Threshold. I would double check for vacuum leaks and make sure ALL connections and hoses aren't split or loose; use zipties to tighten connections. I have a fault verification process to help narrow it down. The two possibilities for the code is bad HO2 sensor or bad cat. Again, for the Verification Process PM me and I'll email you the process to help get you closer to the correct failed component.
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Old 10-04-2018, 10:42 PM   #7
Stevenjr93
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Quote:
Originally Posted by 02SportWagon View Post
-For your front diff/transmission, I highly recommend Subaru Extra-S, which is now called "Subaru High Performance Gear Oil". I run it in my 02 WRX and it helped with a lot of transmission/differential noise and hard shifts. Flat Irons Tuning has it on sale.

-For the clunks, its most likely your transmission mount bushing worn out and your pitch stop aka "dog bone" that attaches your engine to the fire wall is working to fight that. If the valve covers are leaking, I would bet that your engine mounts are toast as well. Group N engine and trans mounts helps with that as they're a bit stiffer rubber. I would recommend their dog bone as well.

-As for clutch pedal feel. I would inspect the whole assembly and system. I've got the whole adjustment and spec sheet. PM me your email and I can shoot it to you.

-P0402? I've heard of P0420, which is Cat Inefficiency Below Threshold. I would double check for vacuum leaks and make sure ALL connections and hoses aren't split or loose; use zipties to tighten connections. I have a fault verification process to help narrow it down. The two possibilities for the code is bad HO2 sensor or bad cat. Again, for the Verification Process PM me and I'll email you the process to help get you closer to the correct failed component.
So shortly after I posted this, my slave cylinder blew; which I think was the cause of several of these issues. Obviously the pedal problem, as well as maybe the rough shifting since it's been better.

My P0420(yes, sorry) light finally dissapeared after doing the $5 mechanical non fouler trick, it came back once. Guess the ECM had logged info before I threw it in, so once I cleared it it's been gone for over a week now with regular long highway drives.

Bad news; my bearings and viscous coupler in my center diff are going so Im getting ready to fix that; and I can't fix my EVAP problem; filling up takes forever. Had it partially diagnosed at the shop while they were fixing my slave cylinder and they said my canister vent valve was stuck closed. Swapped that for a new one today and it still hasn't corrected my problem. Canister itself seemed in good condition; so im kind of at a loss now what to check/replace?
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Old 10-08-2018, 11:05 AM   #8
02SportWagon
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97 SNW Legacy Brighton

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That's a bummer!
So you replaced the canister vent valve as it was stuck closed? Was it full of dirt/debris? If I were you, I would inspect the line running from your tank to the valve for dirt/debris by running something flexible down it(like weed-eater line). Make sure the vent hose at the filler neck isn't clogged. If the hoses running from the tank to the valve and from the valve to the canister are clear and flow easily. I would suspect your fuel tank Vent Valve is failing. It is on top of the fuel tank and controls fuel vapor when fueling. Subaru PN: 42084FA161
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Old 10-15-2018, 11:30 PM   #9
Stevenjr93
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Update! After a long struggle and 10+hrs of wrenching, i finally replaced all the bearings and the center diff; no more whine and no more wheel hopping on tight lock turns! I'm stoked how quiet the cabin is now; and now with motul300 front and back the car feels much better. Two problems less to think about!

Haven't had the time or heart to further investigate the filling issue, gonna wait a bit until Im not so burnt out in DIY mechanics haha. Other than that theres just a random tapping noise coming from somewhere on the drivers side... its intermittent and doesn't correspond with any RPM/speed/clutch/braking. Sounds almost like something inside my door is moving around or something, driving me crazy!!
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