Stock Supercharger PSI - Code P0033 Bypass Valve

GoblinGuyZ

GoblinGuyZ

Well-Known Member
Wondering what you guys are getting as max psi in 2nd gear from stock LSJ. Mine is 2006. I'm seeing 9-10 psi max from mine and wondering if that's normal. Just usual DF Intake and a custom exhaust. Engine has healthy compression 215 or so across all cylinders and vacuum seems fine.

I am getting code P0033 Turbo Bypass Valve which would make sense if I have an issue with this.

The vehicle was built when I purchased it but I noticed two unused harness connectors in the area of the bypass valve and wondering if I'm missing anything needed for the bypass to function correctly. TIA

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Sparvy

Sparvy

Active Member
GoblinGuyZ said:
Wondering what you guys are getting as max psi in 2nd gear from stock LSJ. Mine is 2006. I'm seeing 9-10 psi max from mine and wondering if that's normal. Just usual DF Intake and a custom exhaust. Engine has healthy compression 215 or so across all cylinders and vacuum seems fine.

I am getting code P0033 Turbo Bypass Valve which would make sense if I have an issue with this.

The vehicle was built when I purchased it but I noticed two unused harness connectors in the area of the bypass valve and wondering if I'm missing anything needed for the bypass to function correctly. TIA

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Those look like the evaporative emissions plugs. Most people don't keep them...I did just in case I ever need or want to put the canister back on. I hit 16psi in second gear but am tuned with a smaller pulley and other mods to support it. Not sure what the stick "setting" is supposed to be.
 
GoblinGuyZ

GoblinGuyZ

Well-Known Member
Sparvy said:
Those look like the evaporative emissions plugs. Most people don't keep them...I did just in case I ever need or want to put the canister back on. I hit 16psi in second gear but am tuned with a smaller pulley and other mods to support it. Not sure what the stick "setting" is supposed to be.
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Ok cool yes I get codes for the Evaporative system as well but I ignored them. Other than that and the Fuel tank pressure nothing else besides the Bypass valve. I just want to make sure it's nothing obvious before I go and buy a replacement Bypass valve for $100
 
GoblinGuyZ

GoblinGuyZ

Well-Known Member
Came across this post so now I'm confused and wondering if something is indeed missing...

dfkitcar.com

06 SS/SC Vacuum Line routing

I am in the process of troubleshooting a bit of performance and I think I have narrowed it down to the vacuum lines. When I got the donor the lines were in rough shape and dry rotted. I think that when I replaced them I may have missed/swapped some lines. Does anyone have a good diagram/photo...
dfkitcar.com dfkitcar.com
 
ctuinstra

ctuinstra

Goblin Guru
You don't actually have to have the boost solenoid but the line has to be plugged to prevent vacuum leaks.

I see the blue vacuum line leading to the intake, is that connected somewhere under there?

Basically the boost solenoid is to open the bypass valve to bleed off boost. This is done to prevent overboost and control boost say in first gear to prevent too much boost.

I wonder if yours is connected to vacuum and the bypass is active all the time.

Although you shouldn't expect 15-16psi of boost with the OEM pulley.
 
GoblinGuyZ

GoblinGuyZ

Well-Known Member
ctuinstra said:
You don't actually have to have the boost solenoid but the line has to be plugged to prevent vacuum leaks.

I see the blue vacuum line leading to the intake, is that connected somewhere under there?

Basically the boost solenoid is to open the bypass valve to bleed off boost. This is done to prevent overboost and control boost say in first gear to prevent too much boost.

I wonder if yours is connected to vacuum and the bypass is active all the time.

Although you shouldn't expect 15-16psi of boost with the OEM pulley.
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Yes its connected. From what I see it would normally go in the solenoid and then come out and go back into where it is now so basically looks like the solenoid was removed. Would that trigger the code is the question. And still doesn't explain why I'm only getting 9 or so psi on WOT.
 
Ross

Ross

Goblin Guru
I get about 10 PSI of boost normally. Depending what RPM you are at when you punch it. Also other variables... 12 PSI is about max I have seen on the boost gauge. Stock LSJ.
 
RCK605

RCK605

Well-Known Member
What is your custom exhaust setup? A free flowing exhaust, especially one with headers and no cats, will reduce boost pressure. Since you have good compression, 9/10 psi, and car is running smooth then I wouldn't worry too much about it. Might not hurt to solve the problem that is throwing the code, but if it were my car I wouldn't let that stop me from driving it.
 
GoblinGuyZ

GoblinGuyZ

Well-Known Member
RCK605 said:
What is your custom exhaust setup? A free flowing exhaust, especially one with headers and no cats, will reduce boost pressure. Since you have good compression, 9/10 psi, and car is running smooth then I wouldn't worry too much about it. Might not hurt to solve the problem that is throwing the code, but if it were my car I wouldn't let that stop me from driving it.
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ok yeah makes sense. It’s not that far off from what I’m expecting and I figured it may have dropped with the higher flow. I have a zzp stage 2 kit to install with a 3.0 pulley so just wanted to make sure everything was good before doing that. I ordered a solenoid and new bypass valve so I’ll see if that takes care of the code.
This is my exhaust. Zzp shorty header into custom vibrant setup.

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ctuinstra

ctuinstra

Goblin Guru
You are getting the code P0033 because you are missing the solenoid. The ECM is not seeing it in the circuit.
 
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GoblinGuyZ

GoblinGuyZ

Well-Known Member
So today I decided to pull the vacuum line that goes from the lower valve nipple to the engine (blue line in my pics above) and block it from the engine side and instantly 15psi. Car pulls much better and feels alot faster. Not sure that psi level is safe on stock map but it proves to me the actual actuator is probably the issue. Just updating in case someone has the same issue in the future.
 
ctuinstra

ctuinstra

Goblin Guru
GoblinGuyZ said:
So today I decided to pull the vacuum line that goes from the lower valve nipple to the engine (blue line in my pics above) and block it from the engine side and instantly 15psi. Car pulls much better and feels alot faster. Not sure that psi level is safe on stock map but it proves to me the actual actuator is probably the issue. Just updating in case someone has the same issue in the future.
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Having that line ported to your intake cause it to limit the amount of boost all the time. The solenoid (that you are missing) regulates the amount of boost bypass. When there is a lot of pressure (boost) in the intake port, this pressure is pushing (via the tubing) on the lower side of the valve causing it to open, thus lowering the boost pressure. This limits the boost. Blocking that line no long limits the pressure. This is how we have our car set up. Glad to hear you made progress.
 
Robinjo

Robinjo

Goblin Guru
I see 15 psi on a 3.0 pulley. Well, when I’m brave enough to go that far….
Loogle says the stock LSJ should get to 12.5 psi.
 
GoblinGuyZ

GoblinGuyZ

Well-Known Member
ctuinstra said:
Having that line ported to your intake cause it to limit the amount of boost all the time. The solenoid (that you are missing) regulates the amount of boost bypass. When there is a lot of pressure (boost) in the intake port, this pressure is pushing (via the tubing) on the lower side of the valve causing it to open, thus lowering the boost pressure. This limits the boost. Blocking that line no long limits the pressure. This is how we have our car set up. Glad to hear you made progress.
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Great. So you have yours blocked permanently. Just concerned I cause damage like that. I have the solenoid and a new valve coming in but if I can keep it like this I'm cool with that too
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
GoblinGuyZ said:
So today I decided to pull the vacuum line that goes from the lower valve nipple to the engine (blue line in my pics above) and block it from the engine side and instantly 15psi. Car pulls much better and feels alot faster. Not sure that psi level is safe on stock map but it proves to me the actual actuator is probably the issue. Just updating in case someone has the same issue in the future.
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The stock MAP sensors - at 1.5 bar - should be good for 21 PSI max boost.
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
The ratings for pressure readings are above nominal atmospheric pressure - 1 bar or 14 PSI - which is the reference that the boost (or vacuum) measurements are made from. So technically the stock MAP is reading the atmospheric 1 bar reference plus the 1.5 bar above to measure the boost of the SC or TC.
 
G

Gtstorey

Goblin Guru
Boost on the LNF is defined as the Boost sensor Low Resolution PID - Atmospheric Pressure PID.

Never mind. I think DS is saying the stock 2.5bar map can read 1.5bar of boost. not that a 1.5bar map can read 1.5 bar of boost.
 
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