Subaru purge valve operation

[D60]

Working on an '02 Forester normally aspirated.

Regarding the evap purge valve in the engine bay on passenger side of engine kinda tucked under the intake manifold: should you not be able to blow through it in either direction?

I cannot blow through from firewall to intake, which I believe would be normal operational flow. I can also clearly tell it opens/closes in test mode.

However I CAN blow from intake manifold port toward firewall in either electrical state.

I don't know if this is normal, or signifies a weak valve which would potentially cause a "small leak" code.

 

[fantastic]

Working on an '02 Forester normally aspirated.

Regarding the evap purge valve in the engine bay on passenger side of engine kinda tucked under the intake manifold: should you not be able to blow through it in either direction?

I cannot blow through from firewall to intake, which I believe would be normal operational flow. I can also clearly tell it opens/closes in test mode.

However I CAN blow from intake manifold port toward firewall in either electrical state.

I don't know if this is normal, or signifies a weak valve which would potentially cause a "small leak" code.

I don't know anything really about these but do understand their function after internet reminder search. Just trying to think logically the valve doesn't open when blown towards the intake & the computer determines when that valve opens. That sounds normal. Now, blowing the opposite direction sounds like the way the valve moves or plunges allow for it to be pushed backwards & consequently opens. To me it sounds like it's working but I'd try to get a simple hand air pump gauge to check it's leakage blowing towards the front. If it holds then I'd imagine it's good. Then pumping it up again while activating 12v should release that pressure. Of course being an 02' anything is possible at that age.

 

[D60]

My neighbor brought me the next gen purge valve from a parts vehicle (he didn't understand I was working on an '02) and you can not blow through it in either direction. Also from at least one video I watched he did not appear to be able to blow thru either port -- although he did not explicitly say that and videography was poor

O'Reilly is supposed to bring me a new Standard today so I'll be curious to see how it behaves

 

[Nukeman7]

I just received a new purge valve from Amazon last night. While it is for a 2010 Hyundai instead of a Subaru, the valve restricts airflow in both directions when de-energized. Same circumstances for the purge valve I replaced on a Jeep last year.

 

[SubieRubyRoo]

Paging @Trav, the Subaru Evap guru

 

[Nukeman7]

Paging @Trav, the Subaru Evap guru

Or @AutoMechanic, our favorite Subaru Tech who turned the ripe young age of 22 yesterday!

 

[D60]

Ok, O'Reilly showed up around 10a with the SMP. You canNOT blow through it in either direction when not energized.

I broke one nipple off the old one, which then became a fun game of extraction with a screw and a heat gun to soften the vac hose.

The few videos I found tout this r&r as "Easy!!" but I find it a moderate PITA solely because access and line of sight are limited.

 

[Nukeman7]

Ok, O'Reilly showed up around 10a with the SMP. You canNOT blow through it in either direction when not energized.

I broke one nipple off the old one, which then became a fun game of extraction with a screw and a heat gun to soften the vac hose.

The few videos I found tout this r&r as "Easy!!" but I find it a moderate PITA solely because access and line of sight are limited. View attachment 215887

You are almost home now! By the way, what was the CEL "small leak" code you were getting that triggered this repair?

 

[D60]

You are almost home now! By the way, what was the CEL "small leak" code you were getting that triggered this repair?

Well, this time a P1443 which did not go away from previously replacing the vent valve at right rear, and P0442.

The owner also complained of hard starts after filling up.

I stumbled upon this thread where a new purge valve actually can cure the 1443, and almost surely causes the hard starts after filling
https://www.subaruforester.org/threads/2004-impreza-p1443-cel-code-evap-system-solved.255610/

I can't be sure the P0442 was from the purge valve, but we're gonna find out!

I just ran thru the self-testing mode again and confirmed that when not energized I cannot blow EITHER direction when installed in vehicle, so I'm sure the old valve was bad

 

[fantastic]

Nice to have a new part for troubleshooting. Good work & hope it removes the CEL. Does this Subaru have over 150k?

 

[D60]

Nice to have a new part for troubleshooting. Good work & hope it removes the CEL. Does this Subaru have over 150k?

415,700 miles. Not kidding. They claim original engine but I'm VERY skeptical.

 

[fantastic]

415,700 miles. Not kidding. They claim original engine but I'm VERY skeptical.

Awesome if true! There should be numbers on the engine somewhere to confirm the year of manufacture.

 

[D60]

I'm just gonna revive this because the saga continues and the struggle is real...

The vehicle is back with a P1443 and P0304. The latter is "new" and almost surely leaking valve cover(s).

I believe the P1443 returned almost immediately after I last dealt with this in April '24 and she's just been driving it.

I started again looking at the purge solenoid. I found that sometimes I could cause it not to work by simply blowing in backwards with my mouth. Now I dunno how much pressure the average person produces blowing through their lips, but it can't be a lot. And I wasn't TRYING to do a huff 'n puff 'n blow the solenoid down kinda blow.

I know in operation these only expect to see flow one way, but it seems to me it should be strong enough to seal against my "lip PSI" even in reverse ‐‐ sometimes it would, sometimes it wouldn't.

I did try spraying a little WD40 through it because it seems like it's "sticky," but this made no difference. I was in test mode so the solenoid gets exercised every, what, 15 seconds?

Thus, I'm warrantying the SMP CP610. O'Reilly has now stopped carrying this in favor of their house brand Import Direct. It's like $5 MORE my cost but I'm sure their profit margin on a house brand is far greater. Wonderful.

NOW, I started wondering about what else might contribute to premature failure. I read somewhere to blow out the line from the purge solenoid to the charcoal canister. This seems prudent, so I did that.

I wonder if charcoal pieces or particulates could cause the solenoid to stick if ingested??? As such I inspected the canister but didn't find the glacial flow of charcoal that I have from other Subaru canisters.

Nonetheless I blew a little air in one port and did get some charcoal dust. This might be normal, though -- I have no idea.

I ordered a new canister anyway. I weighed the old one at an ounce under 4 lbs

I scraped/blew off 98% of the dirt so as to not affect the weight significantly.

A new one is 2lb 13oz:

Somewhere online before I've found concrete specs on weight limits. I seem to recall the threshold was something like 3lbs 8oz? I searched and couldn't find it in any Google result.

I also cleaned the PCV for good measure, although this shouldn't affect a darn thing for evap. It was rattling before but really dirty.

So....we'll see. I'm just trying to give this new purge solenoid the best chances for survival.

The odometer now reads 425k mi....

 

[D60]

I remember the first time around (April '24) I had some difficulty getting the new solenoid hung under the IM, but I got it.

This time I simply could NOT get it to work out, no matter how many magnets, swivels, inspection mirrors and nut-grip sockets I employed.

I will say: there's absolutely ZERO reason for the solenoid to be where it is. You could move it top-side and simply extend the two vacuum hoses and the electrical wires. Seems to me you could also move to the '05+ solenoid which seems to sell for considerably less. Presumably you'd need to get the '05+ electrical connector but this is far from insurmountable.

Anyway, you can see here where it needs to go:

I finally decided to just make an M8x1.25 stud. Install stud, hang solenoid, Install nut. SOOOO much easier. I used the ol' spark plug trick of vacuum hose to start my stud -- worked great!

While Subaru has a love affair with 12mm hex, the common M8 nut is 13mm and that's all I had in my metric fasteners. As such I labeled the IM so the next guy doesn't curse me:

 

[D60]

Just finished a 29.5 mi test drive and so far no codes or pending codes.

I'm cautiously optimistic this is solved for now.

Was it just a bad purge solenoid from Standard (not their T series)? Maybe.

Did something get pulled into the solenoid because I didn't blow out the line to the charcoal canister last time? Maybe?

Did the new charcoal canister I just installed help the problem? A big "maybe"

Either way it's working. I really like the EJ25 with a manual transmission. No nannies, no electric parking brakes, no AutoPark. Surprisingly refreshing. Too bad I don't like Subarus and have zero use for a car or a wagon

 

[fantastic]

Give yourself a pat on the back . 10 for effort and not too bad to throw parts at it to see what happens. Hope it works out this time.

 

[brages]

I had a go round with evap codes on my 1997 Ranger and the only fix was getting a NOS purge valve and solenoid from Ebay. The aftermarket stuff (including Standard) kept throwing codes.