Air Injection Solenoids and why you get a CEL
03-08-2012, 01:44 PM
#1
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Air Injection Solenoids and why you get a CEL
One of the issues we have been hearing a lot about, getting calls on, and personally seeing for ourselves is these Air Injection Solenoids having issues on the 06+ model vehicles. Remember the air pump is suppose to only run for a short moment under start up (it injects oxygen into the exhaust to burn off the excess fueling at the catalytic converters so they will lite off).
Here you can see both of these bad solenoids and how gummed up they're getting from exhaust gases and moisture. The check valve get's damaged forcing it to be stuck open, which causes constant hot exhaust gases to run through these parts, you can see the seal on the plunger is literally destroyed from the heat.
I really hope SOA realizes this is not an issue that's going to go away. In the last week we have taken 5 phone calls in regards to this and today we are fixing a customers...which in time will have the same fate as his last ones unfortunately. Hopefully SOA steps up and has a revision and/or compensation (warranty) in place for this issue in near future. Subaru current warranty rebuttal is they claim these parts are not an "emissions" related component but it clearly is and they need to admit to it and fix this issue.
*Yes, you can remove them but it will require getting into the ECU to turn off the codes, install of aftermarket block off plates.............and then you have potential smog repercussions in the lovely state of CA if you delete the system from the car.
-Noah
Here you can see both of these bad solenoids and how gummed up they're getting from exhaust gases and moisture. The check valve get's damaged forcing it to be stuck open, which causes constant hot exhaust gases to run through these parts, you can see the seal on the plunger is literally destroyed from the heat.
I really hope SOA realizes this is not an issue that's going to go away. In the last week we have taken 5 phone calls in regards to this and today we are fixing a customers...which in time will have the same fate as his last ones unfortunately. Hopefully SOA steps up and has a revision and/or compensation (warranty) in place for this issue in near future. Subaru current warranty rebuttal is they claim these parts are not an "emissions" related component but it clearly is and they need to admit to it and fix this issue.
*Yes, you can remove them but it will require getting into the ECU to turn off the codes, install of aftermarket block off plates.............and then you have potential smog repercussions in the lovely state of CA if you delete the system from the car.
-Noah
03-08-2012, 03:13 PM
#3
The best part is that if they stick open and the car is run like this for a while, you run the risk of damaging exhaust valves, valve guides, and even warping the head. This is because fresh air is being introduced into the exhaust port causing very high EGT's. We've seen this on more than a few cars now.
Its such a problem prone system that we do recommend removing it and installing block-off plates on most vehicles. The system is only used on cold start, so it won't effect emissions testing as long as you leave the pump itself in for the visual inspection.
-- Ed
Its such a problem prone system that we do recommend removing it and installing block-off plates on most vehicles. The system is only used on cold start, so it won't effect emissions testing as long as you leave the pump itself in for the visual inspection.
-- Ed
03-08-2012, 03:21 PM
#4
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The best part is that if they stick open and the car is run like this for a while, you run the risk of damaging exhaust valves, valve guides, and even warping the head. This is because fresh air is being introduced into the exhaust port causing very high EGT's. We've seen this on more than a few cars now.
-- Ed
-- Ed
The pump only runs after start up...its only on for a short amount of time. Once its off, there is no air flowing through the system. Its quite the opposite, the exhaust pressure is always higher therefore its actually going backwards (back pressure) towards the valve, as evident of exhaust/carbon in the valve assembly (which is what is damaging them).
We've seen bad valve guides too but that comes from cars running too lean and nothing to do with these solenoids. Typically its faulty tuning.
-Noah
03-08-2012, 03:30 PM
#5
I've learned that I can't go fully to the floor. I get the same pull with my food just a tad off the floor and I don't detonate. LOL! Oh... and I joined the 200,000 club. I know we talked about that before. Seems these motors are more durable than the early day reputation would lead you to believe! And I have another toasted turbo.
03-08-2012, 03:45 PM
#6
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Are they still running the open/closed loop system in the stock tuning? I know with mine (04) it's TERRIBLE and causes a ridiculous amount of detonation under heavy pedal work.
I've learned that I can't go fully to the floor. I get the same pull with my food just a tad off the floor and I don't detonate. LOL! Oh... and I joined the 200,000 club. I know we talked about that before. Seems these motors are more durable than the early day reputation would lead you to believe! And I have another toasted turbo.
I've learned that I can't go fully to the floor. I get the same pull with my food just a tad off the floor and I don't detonate. LOL! Oh... and I joined the 200,000 club. I know we talked about that before. Seems these motors are more durable than the early day reputation would lead you to believe! And I have another toasted turbo.
They all have open/closed loop but your 04 is different than 06+, not sure what any of that has to do with this post though. If your car is detonating, it must not be too bad as its made it 200k+. On the flip side, it shouldn't be detonating
2.0L's are of the most resilient motors we see come through our shop (maybe it has to do with the mileage and time they have been out there vs. the other ones but they defiantly are not crap and a POS like some like to spread on the internet).
-Noah
03-08-2012, 03:49 PM
#7
Your car doesn't have these solenoids, so it doesn't apply.
They all have open/closed loop but your 04 is different than 06+, not sure what any of that has to do with this post though. If your car is detonating, it must not be too bad as its made it 200k+. On the flip side, it shouldn't be detonating
2.0L's are of the most resilient motors we see come through our shop (maybe it has to do with the mileage and time they have been out there vs. the other ones but they defiantly are not crap and a POS like some like to spread on the internet).
-Noah
They all have open/closed loop but your 04 is different than 06+, not sure what any of that has to do with this post though. If your car is detonating, it must not be too bad as its made it 200k+. On the flip side, it shouldn't be detonating
2.0L's are of the most resilient motors we see come through our shop (maybe it has to do with the mileage and time they have been out there vs. the other ones but they defiantly are not crap and a POS like some like to spread on the internet).
-Noah
03-08-2012, 04:19 PM
#8
Don't agree with you and this is why.
The pump only runs after start up...its only on for a short amount of time. Once its off, there is no air flowing through the system. Its quite the opposite, the exhaust pressure is always higher therefore its actually going backwards (back pressure) towards the valve, as evident of exhaust/carbon in the valve assembly (which is what is damaging them).
We've seen bad valve guides too but that comes from cars running too lean and nothing to do with these solenoids. Typically its faulty tuning.
-Noah
The pump only runs after start up...its only on for a short amount of time. Once its off, there is no air flowing through the system. Its quite the opposite, the exhaust pressure is always higher therefore its actually going backwards (back pressure) towards the valve, as evident of exhaust/carbon in the valve assembly (which is what is damaging them).
We've seen bad valve guides too but that comes from cars running too lean and nothing to do with these solenoids. Typically its faulty tuning.
-Noah
-- Ed
03-08-2012, 04:21 PM
#9
Your car doesn't have these solenoids, so it doesn't apply.
They all have open/closed loop but your 04 is different than 06+, not sure what any of that has to do with this post though. If your car is detonating, it must not be too bad as its made it 200k+. On the flip side, it shouldn't be detonating
2.0L's are of the most resilient motors we see come through our shop (maybe it has to do with the mileage and time they have been out there vs. the other ones but they defiantly are not crap and a POS like some like to spread on the internet).
-Noah
They all have open/closed loop but your 04 is different than 06+, not sure what any of that has to do with this post though. If your car is detonating, it must not be too bad as its made it 200k+. On the flip side, it shouldn't be detonating
2.0L's are of the most resilient motors we see come through our shop (maybe it has to do with the mileage and time they have been out there vs. the other ones but they defiantly are not crap and a POS like some like to spread on the internet).
-Noah
-- Ed
03-08-2012, 04:53 PM
#10
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You're right for WOT/boost conditions but not during cruise. At cruise there is not as much gas volume and back pressure. The fast flowing exhaust gas creates a venturi effect which will actually suck in fresh air from the open solenoid. The pump does not need to be on for this to happen as air can still flow past the pump when its off. This is very similar to what happens with a large leak at the header flange. A large enough leak can introduce enough fresh air behind the exhaust valves to actually damage valves and burn seals even under cruise conditions.
-- Ed
-- Ed
Simply think about what would happen if you removed the solenoids from the equation. You would have an exhaust leak blowing exhaust through the tubes, not sucking. In a turbo system you have constant back pressure...how much pressure that is, not sure but I wouldn't think enough to create what you're suggesting...but that's just my thinking.
-Noah
03-08-2012, 05:11 PM
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For what its worth...we have sent all our images and concerns to SOA.
We'll see what they have to say.
-Noah
We'll see what they have to say.
-Noah
03-08-2012, 05:35 PM
#12
Simply think about what would happen if you removed the solenoids from the equation. You would have an exhaust leak blowing exhaust through the tubes, not sucking. In a turbo system you have constant back pressure...how much pressure that is, not sure but I wouldn't think enough to create what you're suggesting...but that's just my thinking.
-Noah
-Noah
It all depends on how much back pressure, gas velocity, and the size of the opening/leak. At cruise there is very little to no back pressure even on a turbo car but the velocity is still enough create a venturi effect over a relatively small opening such as a stuck solenoid.
I've spoken with several old school engine builders about this and its a very well known issue with smog pump systems like this. I've also seen very few non-smog pump cars have valve guide issues, while almost every smog pump car we take apart ends up needing exhaust guides. This is enough evidence for me to recommend removing the system.
But hey.. we can agree to disagree
-- Ed
03-08-2012, 06:05 PM
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It all depends on how much back pressure, gas velocity, and the size of the opening/leak. At cruise there is very little to no back pressure even on a turbo car but the velocity is still enough create a venturi effect over a relatively small opening such as a stuck solenoid.
I've spoken with several old school engine builders about this and its a very well known issue with smog pump systems like this. I've also seen very few non-smog pump cars have valve guide issues, while almost every smog pump car we take apart ends up needing exhaust guides. This is enough evidence for me to recommend removing the system.
But hey.. we can agree to disagree
-- Ed
I've spoken with several old school engine builders about this and its a very well known issue with smog pump systems like this. I've also seen very few non-smog pump cars have valve guide issues, while almost every smog pump car we take apart ends up needing exhaust guides. This is enough evidence for me to recommend removing the system.
But hey.. we can agree to disagree
-- Ed
Agreed, we can agree to disagree...or just say our business's vary on our findings. To each's own.
-Noah
Last edited by LICmotorsports; 03-08-2012 at 06:13 PM. Reason: stupid spell check....
03-08-2012, 06:08 PM
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Picture for reference:
Exhaust gas is just that, a gas, which like a fluid takes the path of least resistance when moving from one place to another.
Add to it the pumping effect of the piston, and the exhaust stream in our applications, will have positive pressure.
Under boost, the exhaust gas between the exhaust port and turbocharger will have about the same pressure as the intake manifold.
Look at the pictures LIC posted; they show carbon deposits from the exhaust gases backflowing up the fresh air tract.
We have seen several cars with these ****ty valves and the associated CELs.
Some owners have us repair them, others don't
A few of the No Repair customers are still driving after 4+yrs and 50k miles will no issues.
In the last seven years, we've had to replace valve guides on exactly one engine; a DOHC EJ25 N/A with 300k on the clock.
Exhaust gas is just that, a gas, which like a fluid takes the path of least resistance when moving from one place to another.
Add to it the pumping effect of the piston, and the exhaust stream in our applications, will have positive pressure.
Under boost, the exhaust gas between the exhaust port and turbocharger will have about the same pressure as the intake manifold.
Look at the pictures LIC posted; they show carbon deposits from the exhaust gases backflowing up the fresh air tract.
We have seen several cars with these ****ty valves and the associated CELs.
Some owners have us repair them, others don't
A few of the No Repair customers are still driving after 4+yrs and 50k miles will no issues.
In the last seven years, we've had to replace valve guides on exactly one engine; a DOHC EJ25 N/A with 300k on the clock.
03-08-2012, 06:35 PM
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Good info guys. I was just reading related threads on NASIOC as I swapped my 06 engine into another car, and now I have to turn ALL FOURTEEN RELATED CODES OFF.
I kept all of the hardware so that I can smog the swap, but this is a very common and ongoing issue. Hopefully enough of you good shops can put a bug in SOA's ear. Otherwise customers will continue to toss thousands of dollars down the drain.
I tend to agree with Ed: Remove the valves from the heads and block them off. In CA leave everything in place but turn the codes off. If you want to try and dig into the closed loop maps and fix the 15-20 seconds of funky idle go for it...if you even can!! I have been running without them for 4 years now and the only negative is I have to remind Mike to turn the codes off when he tunes my car
For the Do it Yourself'ers out there, this thread is a great start. Otherwise we all know local shops that will take great care of you
http://forums.nasioc.com/forums/show....php?t=1209260
I kept all of the hardware so that I can smog the swap, but this is a very common and ongoing issue. Hopefully enough of you good shops can put a bug in SOA's ear. Otherwise customers will continue to toss thousands of dollars down the drain.
I tend to agree with Ed: Remove the valves from the heads and block them off. In CA leave everything in place but turn the codes off. If you want to try and dig into the closed loop maps and fix the 15-20 seconds of funky idle go for it...if you even can!! I have been running without them for 4 years now and the only negative is I have to remind Mike to turn the codes off when he tunes my car
For the Do it Yourself'ers out there, this thread is a great start. Otherwise we all know local shops that will take great care of you
http://forums.nasioc.com/forums/show....php?t=1209260