When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hey everyone, I'm having a problem with my 07 SS/SC. When I try to accelerate hard in 2nd the car will only make about 4lbs of boost and the engine feels like it's trying to pull itself down almost like something is pulling the car back. I would really appreciate any help, Thanks y'all.
Sounds to me like your bypass actuator is either being opened by the bypass actuator solenoid or is faulty itself. The bypass actuator solenoid will route boost pressure to your bypass actuator diaphragm if the ECU commands it, it doesn't have power, or is faulty. A way to test this is to disconnect the line coming from your solenoid AT the actuator. Leave the actuator (the part physically attached to the supercharger) nipple open to atmosphere. Plug off the line coming from the solenoid that you just disconnected. There should still be a line connected to the nipple on the other side of the actuator diaphragm that connects to the TB for vacuum signal. Leave that line connected. Once you have competed this you can go out for a pull and see if you have boost back.
If you do have boost, the next step will be to figure out if your solenoid is being commanded open or if it isn't functioning correctly.
Sorry it took me awhile to get around to taking a look at it but I did what you said and nothing really changed so I'm wondering now if the lower nipple on the solenoid being unplugged would affect anything, Thanks.
You disconnected the line in your hand and left it open to atmosphere while also plugging the line that goes into the back side of the solenoid in the picture? If you did not plug the line on the back side of the solenoid and the solenoid isn't energized it would be a boost leak.
You do not want to disconnect the line going from the bottom side of the actuator diaphragm to the intake neck of the supercharger. This line allows the supercharger to go into bypass mode when it is pulling vacuum on the back side of the throttle body. This prevents your supercharger from trying to suck air past a closed throttle body. The only way it could cause a drop in boost with WOT is if your air intake tract is clogged or your throttle body is partially closed for some reason. So this line would never be the cause just a symptom of a different problem.
Did you visually inspect the actual actuator attached to the supercharger body? It should be closed in it's at rest position. You can also make sure it is moving freely by manually moving the rod down with your hand and then when you release it should spring back into the upward position.
Everything appears to be working as it should. The knock sensor has been setting codes but it's definitely not knocking (completely sure its just the sensor going out). Would that cause it to reduce power and boost? It does it even if the CEL is off, so I really don't know.
I'm not sure what it defaults too if the knock sensor is throwing codes though I do the knock sensor can for sure pull power if it thinks it is detecting knock. Do you have an ODBII reader? You can look at your commanded throttle position to see if your ecu is commanding the throttle to close down partially for some reason.
08-30-2018, 10:19 AM
