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Old 10-05-2018, 07:57 PM   #109
Scooby Specialist
Member#: 191557
Join Date: Oct 2008
Chapter/Region: TXIC
Location: Rockwall-East DFW
2004 WRX Wagon
WRB not so minty fresh


Originally Posted by TXwrxWagon View Post
Po457 back again... grrrr.... about a month or so ago I did the recommended "purge delete", installed a new OE Subaru gas cap. OE Subaru Evap Solenoid. Wire ties and got rid of all the other stuff as outlined.

PERFECT! problem solved. went away until today. I'm fighting a surging boost issue and have isolated it to the EBCS. So I have been staying out of heavy boost. Got a little boost heavy in an avoidance maneuver today (about 12-14psi) and after I backed off and settled to cruise, I look down ORANGE dang light again!

I'm picking up a Walbro pump tomorrow evening to swap and will check everything at the fuel pump stand end. but this is getting crazy. How can it be fine and not even hit full boost and all the sudden P0457 leak/loose fuel cap come back!?

Well, well, 3 years almost to the day. 100K miles more And here I am again... time for inspection and the car won't go to ready mode on the OBDII, and then the CEL's start.

Codes: P0457 with the JDM Vacuum routing. and now the P0131, also (lean bank 1) with a vengeance and progressively every damn gas pump across the south and central USA pops every .60-.90 gallons like clock work.

So again I reach for the wallet:

Tank Fill tube (Rockauto)

Tank fill roll over valve (Rockauto)

Canister (OE this time from Rockauto)

Purge solenoid (front, OE/DENSO, Rockauto)

Purge Vent (rear, OE/DENSO, Rockauto)

All new OE molded hoses for the canister (a cool $148 from the Dealer)

Replaced all the vacuum and emissions hoses from the filler neck to the top of the tank.

All lines over vacuum sized, I used Gates Power grip heat-shrink clamps and teflex covering. Everything small got seriously zip tied, as I found 2 loose and one big line almost off.

Fresh canister drain hose from canister to tank

Also resistance checked the $200+ fuel tank pressure valve and the equally $200+ EGR Pressure Relief valve (above purge vent on bracket), and double checked the fuel pump stand gasket for any signs of leak/seep.

Lastly, undid the purge vent hard line up front and blew out the hard line from the back all the way out the front.

Essentially the entire EVAP system is new or refurb. 110%

Cleared codes, reset ECU.


1. I read that any charcoal canister should be virtually feather light, no substantial weight, mine was heavy enough to drop from the bracket with a thud to the concrete.

The Wells/Airtex canister had approx 1 cup/8oz of raw fuel poured out in liquid form. and probably another 1/2 cup was leaking before I saw it. I used to be a chronic overfill/topper-offer rounding up my fuel purchase to even $$ for my expense reports. for the last 4 years , when the system stops at 85% full, I stop. so I know for a fact I didn't overfill.and yet, after draining the raw fuel, the canister was still noticeably heavy compared to the new OE unit. hmmmm.. the plot thickens.

2. blowing the hard line clean resulted in charcoal from the canister was in the line, just a few pieces, but it was migrating, not a good sign.

3. the REALLY interesting find: the exit hose (hose going from purge solenoid to the intake, the nipple closest to the connector) was completely plugged with carbon and charcoal, over a thimble sized pile had made it through the solenoid and plugged up the vacuum line! luckily it didn't make it into the intake tract!

So I replaced all the vacuum lines under the hood, replaced the purge solenoid, etc. I am about to take the upper intake off anyway for TGV-Delete/injectors/pheonolic spacers etc. So my plan to drive it tomorrow, sidelined to check the intake to make sure no contamination.

Just thought I would update the thread.

I will report back mid week next week after its all back together.

Perfect excuse to take 5 days vacation and go Stage 3
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