So I have a question. We had the supercharger off and put it back on and now the car only boosts 12lbs. It has a 2.8 pulley on it and used to go to around 18 when it was cool out. I thought there might be a leak so I did a boost leak test at the throttle body and it held pressure with no leaks. So I checked the bypass valve and couldn't tell if it got messed up somehow. I tried tieing it shut so it couldn't open and it still only went to 12. I figured it would boost more if I tied it shut. Not too familiar with superchargers so I was wondering what you guys thought. I'm probably just going to buy a new bypass valve since they're cheap. I just don't know what else could cause this. I don't hear any abnormal noise from the supercharger and there is no play in pulley. Ideas?

 

check the vac lines you may have hooked them up wrong

 

I checked my buddies car and everything was hooked up the same. I thought I may had done that too. I don't know what it could be. The supercharger sat for like 2 months so I don't know if something could have happened to it. I doubt it. I thought if there was something wrong with the supercharger it's self it would probably sound weird. The supercharger isn't nearly as loud as it used to be. You can barely hear it under full boost. Sometimes it only goes to 10lbs. How accurate are the boost gauges on these cars? I know on the Dsm's the stock boost gauge was just a guess so I was wondering if this was similar. I was thinking about getting a auto meter boost gauge in there when I put the wideband in.

 

heard you're having boost problems and I feel bad for ya son, but I got 99 problems and low boost aint one.

Besides that, is the belt slipping?

 

it could be the boost bypass valve sensor or wutever its callled...its the sensor above where your injector harness plugs into and has 2 or 3 vac lines off it...mine went and i went from 25 psi to 3

 

I don't think the belt is slipping, it doesn't sound like it is anyways. It was a new belt. Is that sensor the one that has the breather thing and the two vacuum lines on it? There are no cels or anything just not boosting right. The car has a little over 30k I can't believe stupid sensors would already be going bad. I'll probably just get that sensor and the new bypass valve and hope that fixes it. I hate to just throw parts at it but I don't know what else to do at this point. The car won't be running for a little bit I'm waiting on a stock exhaust and it's getting crappy here so the car is hibernating in the garage. It was doing it before I put it up for winter so I figured I'd try and get it figured out before I start driving it again. Thanks for the help so far.

Edit** Anyone know about these factory boost gauges?

 

HIT ME

 

They are known to not be 100% accurate, but to be off by 8 psi is not a faulty gauge, it's a broke gauge. If the car feels sluggish then it is a boost issue. The only thing you could have done wrong is the vac lines. Take them off, then reinstall them. There are two nipples that can be use on the boost sensor. Make sure it is the same one as your friend's car. I don't have my car around at the moment to look, but there are to nipples. Put it on the top and not the bottom (or vice versa) and it will not boost correctly. Cracked line vac hose?

 

Can someone take a close picture of that sensor along with the boost sylenoid in the picture too? I want to see how your hoses are hooked up to make sure mine are right. I don't think any vacuum lines are cracked it held pressure when I did a boost leak test.

 

https://www.cobaltss.net/forums/how-...ass-mod-11994/

The old archaic boost bypass mod before PCM reflashes haha. Good for testing purposes now.

That was awesome.

Joel

 

I took a look at my solenoid. It has 3 nipples, back one goes to intake manifold the front top one goes to the top nipple on the bypass valve bottom nipple on solenoid is open and the bottom nipple on bypass valve goes to the supercharger. Is that right? How will taking the back hose off test the bypass valve? Will it boost 18 then if the solenoid is bad an I disconnect that? It doesn't go above 12 now and it's a 10 until like 5k.

Edit*** Never mind I found some pictures on good old google.

 

Did you ever figure out what the problem was? Did the car make any weird noises (hissing) when the motor was under load? Did the boost gauge read slightly lower than normal vacuum at idle?