Secondary air injection
08-08-2005, 10:17 AM
#1
Racer
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Secondary air injection
Had contact with my local P dealer for a key programming. While I was there they ran an engine check. Seems my "secondary air injection" isn't operating. It is running fine, though I percieve a little down on power.
Is there an easy fix? What is involved? Advise?
Rob
Is there an easy fix? What is involved? Advise?
Rob
06-05-2008, 04:57 PM
#3
Drifting
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not familiar with this problem on a boxster, but on a 993 this is a real PITA. However, if it is the same as the 993, this has nothing to do with power. This is part of the emissions system.
Do you have a Check Engine Light on? If not, I'd ignore or get a second opinion (based on my 993 experience)
Do you have a Check Engine Light on? If not, I'd ignore or get a second opinion (based on my 993 experience)
06-06-2008, 09:32 AM
#5
The secondary air injection should not cause a loss of power. It is curious to me that they say it's not working but you don't have a check engine light. If you have a CEL let us know what the codes are, if not, I agree with mborkow - don't worry about it.
06-06-2008, 02:59 PM
#7
Ahhh - I think what we have here is a failure to communicate. What year and engine is it? on 3.4s (and I think later 3.2s & 2.7s) there is a second intake runner that is opened and closed at specified RPM's (4,000 RPM on my 3.4) to change the effective length of the intake manifold. This is far different from the "secondary air injection system" which is, as has been documented, only for cold running emmisions and what your fellow Rennlisters have been trying to fix.
Not all Boxsters have this 2 stage intake, which is why we need to know what year/engine you've got. IF you have the 2-stage intake and IF it was not working properly it would not activate a check engine light, but it would cause a loss of power above 4,000 RPM. (and I guess it could cause a loss below 4,000 if it was stuck closed).
The intake flap is controlled by a vacuum motor which is in turn controlled by an electric valve mounted under the throttle body. The valve gets a 5 volt signal from the ECU when it's time to open, allowing vaccum to close the actuator. You can see if it works simply by taking the engine cover off and revving the engine to 4,500 RPM. You will see the shaft in the intake runner rotate around about 4,000 if it's working. If it's not, check for 5volts in the wire to the vacuum switch at 4000 RPM and if you've got that you most likley have a defective electric valve. A vaccum leak will also cause the system not to work, but it would also cause other things (like the secondary air injection system) to not work, resulting in check engine light so I'll assume you don't have a vacuum leak. Having said that I guess a leak between the elctric valve and the vacuum motor would not cause a CEL but would cause the flap to not close. The electric valve is about $30 (Part#99360512300 last time I bought one) and is, by the way, the same electric valve that controls the secondary air injection system. If you replace it make sure that you orient the 2 vacuum lines the same way they came off or you will cause a new vacuum leak (personal experience!)
Clear as mud?
Good Luck!
Randy
Not all Boxsters have this 2 stage intake, which is why we need to know what year/engine you've got. IF you have the 2-stage intake and IF it was not working properly it would not activate a check engine light, but it would cause a loss of power above 4,000 RPM. (and I guess it could cause a loss below 4,000 if it was stuck closed).
The intake flap is controlled by a vacuum motor which is in turn controlled by an electric valve mounted under the throttle body. The valve gets a 5 volt signal from the ECU when it's time to open, allowing vaccum to close the actuator. You can see if it works simply by taking the engine cover off and revving the engine to 4,500 RPM. You will see the shaft in the intake runner rotate around about 4,000 if it's working. If it's not, check for 5volts in the wire to the vacuum switch at 4000 RPM and if you've got that you most likley have a defective electric valve. A vaccum leak will also cause the system not to work, but it would also cause other things (like the secondary air injection system) to not work, resulting in check engine light so I'll assume you don't have a vacuum leak. Having said that I guess a leak between the elctric valve and the vacuum motor would not cause a CEL but would cause the flap to not close. The electric valve is about $30 (Part#99360512300 last time I bought one) and is, by the way, the same electric valve that controls the secondary air injection system. If you replace it make sure that you orient the 2 vacuum lines the same way they came off or you will cause a new vacuum leak (personal experience!)
Clear as mud?
Good Luck!
Randy
