FAQ: Subaru EVAP Purge Control Solenoid Valve Information for EJ205

[IA Performance]

Assuming the check engine light is for the EVAP purge system, then chances are very high the broken hose end is the culprit. You could try using something stronger, like JB weld, but sand the plastic a bit to give it a rough texture. Then, after it has dried, you may need to chase the hole with a small drill bit to ensure there are no obstructions (glue) left behind.

Stephen

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[Bob Jacobson]

Originally Posted by IA Performance

Assuming the check engine light is for the EVAP purge system, then chances are very high the broken hose end is the culprit. You could try using something stronger, like JB weld, but sand the plastic a bit to give it a rough texture. Then, after it has dried, you may need to chase the hole with a small drill bit to ensure there are no obstructions (glue) left behind.

Stephen

I havent been able to check the code yet, I lost my cheapo bluetooth OBDII scanner when I moved. New one is in the mail.

I am going to take it apart again and see if I can get it together better, otherwise order a new one.

Im also going to re route the lines as shown. Im having some surging issues from 2.5-3.5k rpm, a lot of my vacuum lines are pretty dry and loose so I wouldnt be surprised if I have a vacuum leak from one of them.

[musicmankeb]

What do you do if you are installing aftermarket fuel rails with an aftermarket fuel pressure regulator? Eliminate the purge valve and company all together and disable the codes via accessport? Are these emission codes that need to pass when hooked up to a computer?

[IA Performance]

When migrating to aftermarket fuel rails it will be necessary to run a new vacuum hose from the firewall to the EVAP solenoid. This is what the smallest diameter tube did/does on the stock fuel rails.

Stephen

[musicmankeb]

Stephen:

When you use an aftermarket FPR you need to run the return to that line. So you have to install a T fitting and run that into that line as well?

[IA Performance]

I'm not following the layout. Nothing, other than the EVAP purge, should be tied into it's purge line from the firewall.

FPR Vacuum Source
A fuel pressure regulator (FPR) should always, and I mean always, have its own dedicated vacuum source/hose. Never 'T' the FPR vacuum source in with anything else, including a simple boost gauge.

Feel free to elaborate or include photos if there are additional questions.

Stephen

[musicmankeb]

Originally Posted by IA Performance

I'm not following the layout. Nothing, other than the EVAP purge, should be tied into it's purge line from the firewall.

FPR Vacuum Source
A fuel pressure regulator (FPR) should always, and I mean always, have its own dedicated vacuum source/hose. Never 'T' the FPR vacuum source in with anything else, including a simple boost gauge.

Feel free to elaborate or include photos if there are additional questions.

Stephen

The FPR has a return built into it which goes to your return line obviously. So I'm guessing you want me to put a t in that line and run the purge line to there.

[IA Performance]

I'm sorry, I'm still not following. The fuel system should not tap into the EVAP purge system, if installed properly. The EVAP system is a full standalone item, separate from the FPR, injectors, etc, so do not try to incorporate them. The only tie the EVAP has with the stock (not aftermarket) fuel rails is the vent tube is bolted to the stock fuel rail system. When installing aftermarket fuel rails, this vent tube is removed with the stock fuel rails, and a rubber hose is then run in its place between the firewall and the EVAP solenoid hoses.

If questions still arise, it may be best to consult a professional shop when dealing with fuel.

Stephen

[musicmankeb]

Originally Posted by IA Performance

I'm sorry, I'm still not following. The fuel system should not tap into the EVAP purge system, if installed properly. The EVAP system is a full standalone item, separate from the FPR, injectors, etc, so do not try to incorporate them. The only tie the EVAP has with the stock (not aftermarket) fuel rails is the vent tube is bolted to the stock fuel rail system. When installing aftermarket fuel rails, this vent tube is removed with the stock fuel rails, and a rubber hose is then run in its place between the firewall and the EVAP solenoid hoses.

If questions still arise, it may be best to consult a professional shop when dealing with fuel.

Stephen

Alright I understand how your are saying to hook up this now.

My question is by taking out the purge valve which is a one way valve to prevent you from pushing air out now all you are relying on is the solenoid to open and close and hold boost. Isn't that putting more strain on the solenoid and also couldn't this create a boost leak easier? As soon as your solenoid opens you now have a vacuum leak especially if you are in boost?

[Shiftace420]

Originally Posted by musicmankeb

Alright I understand how your are saying to hook up this now.

My question is by taking out the purge valve which is a one way valve to prevent you from pushing air out now all you are relying on is the solenoid to open and close and hold boost. Isn't that putting more strain on the solenoid and also couldn't this create a boost leak easier? As soon as your solenoid opens you now have a vacuum leak especially if you are in boost?

The purge valve is simply an add on in america due to emission and the ability to purge the evap canister during boost conditions. There is no reason for it other then that and it will not help "protect" your solenoid valve as you said.

The solenoid valve has held perfectly on hundreds of thousands of cars around the world that were not originally equipped with the US design using a purge valve.

[methaddict]

In the process of connecting everything back together in my engine bay. I deleted the purge valve and connected the purge solenoid on my Spec C reversed manifold.

[methaddict]

I had ej207 JDM mod EVAP solenoid hoses connected wrong in the photo above. I had one hose connected to a nipple on the manifold under the throttle body and the other connected to another nipple on to the left of the EVAP solenoid on the manifold. I need to connect one to the pipe C going back to the firewall. Well I had removed the stock fuel lines long time ago and had one hose connected to this pipe C line so I know the others were fuel feed and return.

[coryvismith44]

his might be a dumb question but when i was rebuilding my motor i opted to get rid of the GOB's for easier injector swaps down the line. If i remember correctly the evap purge solonoid is mounted on the passenger side GOB...... now since this rebuild i have been plauged with this code i have tried every plumbing schematic a moderately new evap solonoid (from a reputable ebay seller) and now im wondering does the evap solonoid need to be connected to the Green Bracket Of Death in order to ground itself or something?


The car is a 04 wrx wagon and i have tried everything from the delete to a new engine harness and im still pulling this code evap sensor circuit to high.

Any help would be greatly appreciated

And i mean delete as in the plumbing delete and also getting the code removed by a tuner (also very reputable) and still it pops up after about ten minutes of driving every time

[IA Performance]

GOB = ?, do you mean TGVs? The evap purge solenoid mounts to the underside of the intake manifold. Assuming the EVAP parts are available and in working order, i would plumb them in as either: A) OEM or B) as the JDM version 7 & 8 ej207 (outlined in this post on the first page that deletes the round purge valve).

As for deleting the code, it isn't quite that simple. Not only will the code not stay off indefinitely, there are also EVAP fuel tables that need adjusting.

Stephen

[TXwrxWagon]

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!?

~Rob

[coryvismith44]

Originally Posted by IA Performance

GOB = ?, do you mean TGVs? The evap purge solenoid mounts to the underside of the intake manifold. Assuming the EVAP parts are available and in working order, i would plumb them in as either: A) OEM or B) as the JDM version 7 & 8 ej207 (outlined in this post on the first page that deletes the round purge valve).

As for deleting the code, it isn't quite that simple. Not only will the code not stay off indefinitely, there are also EVAP fuel tables that need adjusting.

Stephen

Thanks stephen and yes i was mistaken about the GBOD**= (Green Brackets Of Death) if you have ever done a inhector swap those are the green brackets that make a 30 minutes job take about 4 or 5 hours :/. But like i stated i have it plumbed as the ej207's are right now and im still getting the circuit to high code. Now right now it is just floating around and not connected to the manifold do you think that would he a isue does it ise the manifold to ground itself?

[coryvismith44]

Hahaha i did not see the IA Performance name originally stephen did not mean to patronize you about injector swaps

[onebadwrx]

nice write up

[chrisroug]

So I did the JDM hook up as well on my 02. Everything was perfect until I had to full it up with gas. From what I can tell the gas tank vent is going into the charcoal canister, and then flows out of the evap hose and runs to the front of the car. If I have the hose hooked up, the car wont fill up with gas. If I unhook the evap line from the firewall the car will fill up just fine. My question is where do the fuel vapors go if you have the JDM solenoid hookup? The solenoid is normally closed, so this creates a block in the fuel vent.

[IA Performance]

I'm not entirely certain where the JDM vent goes. We've done this mod on several 2002-2005 US WRXs without a fill up issue. I'm guessing a line is kinked, clogged, or possibly incorrectly routed. If it will not work on your particular car then there may be something else at play outside of the engine bay area.

Stephen

[chrisroug]

Originally Posted by IA Performance

I'm not entirely certain where the JDM vent goes. We've done this mod on several 2002-2005 US WRXs without a fill up issue. I'm guessing a line is kinked, clogged, or possibly incorrectly routed. If it will not work on your particular car then there may be something else at play outside of the engine bay area.

Stephen

Thanks for the reply! I will dig into this further, and see what it going on. I believe there is another "vent solenoid" that ties into the charcoal canister above it. I know the tank vent works perfectly, so i will look further.

Thanks!

[spoogevac]

Can anybody tell me, if I apply 9 volts to the EVAP Vapor Canister Purge Solenoid Valve should it open, or does it need 12 volts?

Will polarity matter and can I damage it if first try I have the polarity reversed?

Reason I asked is I bought a new one to replace one with snapped nipple from removing intake to fix leaking fuel lines and it wont open under 9 volts.

Id like to know if its a dud before I install it.

[IA Performance]

Originally Posted by spoogevac

Can anybody tell me, if I apply 9 volts to the EVAP Vapor Canister Purge Solenoid Valve should it open, or does it need 12 volts?

Will polarity matter and can I damage it if first try I have the polarity reversed?

Reason I asked is I bought a new one to replace one with snapped nipple from removing intake to fix leaking fuel lines and it wont open under 9 volts.

Id like to know if its a dud before I install it.

Voltage = use 12 volts (car battery or some cordless drills are good sources). I cannot vouch for using too little or too much voltage with the solenoids

Polarity = it should not matter.

Stephen

[spoogevac]

Originally Posted by IA Performance

Voltage = use 12 volts (car battery or some cordless drills are good sources). I cannot vouch for using too little or too much voltage with the solenoids

Polarity = it should not matter.

Stephen

I used drill pack, it worked perfectly.

Thank you so much, I feel like such an idiot now.

[giozara]

Great right on this