There have been a rash of threads recently of people not being able to boost over about 5 psi or over boosting 20+ psi. Don't panic, if your car is still running fine and just not boosting its an easy fix and these are 3 possible issues that can be causing this. Do basic troubleshooting to determine this as well; i.e. taking off the vac lines and replugging them back in, if your car is saying your making 20+ psi of boost but it still runs like normal... etc etc

1. Most likely cause has been the boost bypass actuator. The black cylinder device near the inlet. The spring inside it gets worn out and all you have to do is unblt it from the s/c and replace the entire unit. Get it warrantied or if you want to do it yourself.

2. Second most likely (if your overboosting) is the clogged cat . If your still stock gm has done a recall on the catalytic converter and if you haven't had it replaced yet check your recall notices. Clogged cat isn't as easy as the first fix but you might as well upgrade it if you have the chance to a header/downpipe setup.

3. Next issue is the boost bypass sensor. The sensor is mounted on the engine next to the valve cover. It has black vacuum lines going in and out and has gone out rarely in some cases. Easy fix though and is very cheap replacement through gmpartsdirect.

 

At what RPM are you only boosting 5psi? Everywhere across the board?

 

I'm boosting fine, this is for everyone else lol

 

I thought, typically, if your cat is clogged you will over boost due to the now restrictive exhaust.

 

ahh yess i should clarify that good catch

 

sticky!

 

Mine is jammed at like 5psi until I get into the upper RPMs. If I floor it in 2nd around 3500-4000 it'll boost 12-13psi with a 3" pulley.

 

yours seems like torque management

No problem.

 

Haveing same issue.. Wont boost pass 10psi on my tvs its been on the car for 2 months i got 70 k on the car.. Got a new highflow cat on it and stuff and it started doig this.. Its annoying , if o need to reppace the bypass will the stock m62 bypass work on the tvs?

 

but what about boosting over 20 at 3k rpms with header and catless downpipe? haha yes mine did it one night a few times so i turned it off and unplugged all the vac lines and ecu then put it back together and its running good now, but it only happend when my honda budy was driving it and befor he started he was ******* with all the lights and pressing a **** ton of buttons in the car lol

there is tq management on the ss/sc?

 

the tvs bypass is different, i would say take all of your vac lines off and re plug them in first, it maybe be your sensor!

haha, yea i might say your sensor might be the culprit if it comes back. If your car still behaves like it usually does then the sensor might be giving you a false reading.

 

yeah happend once like 8 months ago and never again. it spikes at 17 every time now.

 

I can see it beinf the sensor im throwin a code for it also p2261 or 2291 one of them

 

my boost bypass spring is really noisey when i move it with my hand is that normal?

 

this is good as it is some common stuff, sticky this bitch

my bypass boost actuator is bad, we just unhooked the hose and put a screw in it haha

the car was slipping at the top of gears like it was trying to boost but was restricted, i was like well i just had the stage 2 belt installed, nope the belt was fine and not slipping.

so my tuner was like pop that hose off haha, did a pull all the way to redline(close to) full boost

i think i should replace that part now tho haha then again the car has been fine too

should i check gm parts direct?

 

i was having problems where up top it would cut out a lil

 

As far as I know, the torque management is turned off in my tune.

HPT should be in the mail in a little bit, so I'll know for sure then. lol

 

any help on mine my car sits at 17 to 18 the it dies and sits at like 5 until i shut it of or drive it easy

 

u mean negative 17-18?

 

no i mean postiive but i have tried somethings but i dont know what to do

 

Now would the air filter have any bearing on the boost? I've only ever seemed to get it up to 10 psi but today I put in a K&N air filter because the car is at 45,000 miles and the old one needed a replacement. I haven't taken it out yet and played with it but I'm wondering if this will change the boost. I noticed on mine that at low RPMs I'll be around 5 - 7.5 psi but once I get to like 3500 it'll get up to 10 psi. I haven't been able to get it much further though or I simply haven't looked when I'm near 5 grand (focusing on the road probably).

 

yesterday i installed the boost bypass valve....the thing with that little sponge on it and i did a test, 1st did a 2nd gear pull pass 6k result: handle boost strong
2nd test was from a dig, 1st handle boost strong and so did 2nd.....

today on the freeway i was in 3rd and took it up to about 6k and it held no struggling of the boost

so i guess i dont need a bypass acuator like i thought....maybe haha



the filter can cause better air flow

 

P0033 Supercharger Bypass Valve Solenoid Control Circuit PCM

i got this code after the install......i had the car in the on position cuz i was listening to music

so the code probably occurred due to the car thinking it was on with the sensor plugged in

haha
i cleared it this morning b4 work

 

Yeah I think the filter had a big effect on the car because I've seen the needle go above 10 psi probably about to 12 psi so I guess I'm good .

Go go K&N!