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Discussion Starter #1
I have a problem with my 2004 WRX sti, I’m not able to achieve full boost. I’m getting anywhere form 9-12 ish, only depending on the temperature outside. The car is stock (as far as I know), I purchased it around late November. So I’m new to Subaru and Turbos in general. With that all being said I am going to need some help and as little abbreviations since I’m not completely up to speed on this.

Steps i have taken:

1. I put it in test mode to check my boost control solenoid it does click and i also ran some carb cleaner through it while it was cycling to clean it.
2. I checked my restrictor pill and found that it wasn’t in the correct location, i put it in the correct place and still no fix (which makes me think it’s not as stock as I was told).
3. I then checked the lines on the compressor and waste gate for cracks and fixed what was visible. Ran it again and still no fix.
4. I then Reset my ECU and pulled the Restrictor pill out completely to see if i could get a spike. No spike in boost, it remained in the 10psi range.

I have a cheap boost gauge so i do expect some accuracy issues, when its off the gauge reads a shy under 0psi so it’s not off by 5psi.

I run around 17-20 inHg in vacuum.
No ECL's.
Slight hesitations at 2k RPM (not always though).



Im waiting on and OBD-II so i can confirm my exact Boost with ROMraider.

I also bought spark plugs to put tomorrow.

Another thing is how easy should the waste gate actuator arm move, By hand?
 

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I have a problem with my 2004 WRX sti, I’m not able to achieve full boost. I’m getting anywhere form 9-12 ish, only depending on the temperature outside. The car is stock (as far as I know), I purchased it around late November. So I’m new to Subaru and Turbos in general. With that all being said I am going to need some help and as little abbreviations since I’m not completely up to speed on this.

Steps i have taken:

1. I put it in test mode to check my boost control solenoid it does click and i also ran some carb cleaner through it while it was cycling to clean it.
2. I checked my restrictor pill and found that it wasn’t in the correct location, i put it in the correct place and still no fix (which makes me think it’s not as stock as I was told).
3. I then checked the lines on the compressor and waste gate for cracks and fixed what was visible. Ran it again and still no fix.
4. I then Reset my ECU and pulled the Restrictor pill out completely to see if i could get a spike. No spike in boost, it remained in the 10psi range.

I have a cheap boost gauge so i do expect some accuracy issues, when its off the gauge reads a shy under 0psi so it’s not off by 5psi.

I run around 17-20 inHg in vacuum.
No ECL's.
Slight hesitations at 2k RPM (not always though).



Im waiting on and OBD-II so i can confirm my exact Boost with ROMraider.

I also bought spark plugs to put tomorrow.

Another thing is how easy should the waste gate actuator arm move, By hand?
It sounds like you have covered most of the bases.

It should require some effort (around 8 pounds to start it).

The cable is the way to go. A boost leak test would also be good.
 

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Discussion Starter #3
It sounds like you have covered most of the bases.

It should require some effort (around 8 pounds to start it).

The cable is the way to go. A boost leak test would also be good.

What is the best way to test it at, the compressor outlet/inlet or after the OEM intake pipe? Any recommended techniques.
 

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There's a fitting you can attach where the air filter goes that has a nipple for compressed air. Then it's just a matter of charging it up and listening for leaks.
 

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Discussion Starter #7
Update

I have a problem with my 2004 WRX sti, I’m not able to achieve full boost. I’m getting anywhere form 9-12 ish, only depending on the temperature outside. The car is stock (as far as I know), I purchased it around late November. So I’m new to Subaru and Turbos in general. With that all being said I am going to need some help and as little abbreviations since I’m not completely up to speed on this.

Steps i have taken:

1. I put it in test mode to check my boost control solenoid it does click and i also ran some carb cleaner through it while it was cycling to clean it.
2. I checked my restrictor pill and found that it wasn’t in the correct location, i put it in the correct place and still no fix (which makes me think it’s not as stock as I was told).
3. I then checked the lines on the compressor and waste gate for cracks and fixed what was visible. Ran it again and still no fix.
4. I then Reset my ECU and pulled the Restrictor pill out completely to see if i could get a spike. No spike in boost, it remained in the 10psi range.

I have a cheap boost gauge so i do expect some accuracy issues, when its off the gauge reads a shy under 0psi so it’s not off by 5psi.

I run around 17-20 inHg in vacuum.
No ECL's.
Slight hesitations at 2k RPM (not always though).



Im waiting on and OBD-II so i can confirm my exact Boost with ROMraider.

I also bought spark plugs to put tomorrow.

Another thing is how easy should the waste gate actuator arm move, By hand?
So i did end up doing a leak test and found that there was a leak at my BOV gasket, but it wasnt that severe so im not sure if it will solve my problem. But i guess im not sure if that leak could keep me from getting 14.5psi.

If it isn't due to the leak what are some other reasons behind the low boost?
 

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Wastegate actuator arm too loose, spring weak.

Car is knocking and the ECU is pulling boost / timing

Restrictor pill wrong size (too large)

Boost gauge is reading high compared to the ECU's data

High elevation

Wastegate duty cycle mapping

Major restriction in exhaust

Incorrect boost control system lines

Low compression

Edit: I didn't mention the BCS because you worked on it, but it is still suspect.
 

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All of the above, but I would put my money on this^^



You need to log, then we can be of more help.
It is a bit of a gamble, but I'm thinking maybe the restrictor pill was changed out, the lines still aren't run correctly or are the wrong ID, or the BCS is bad.
 

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All of the above, but I would put my money on this^^



You need to log, then we can be of more help.
It is a bit of a gamble, but I'm thinking maybe the restrictor pill was changed out, the lines still aren't run correctly or are the wrong ID, or the BCS is bad.
 

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Discussion Starter #12
All of the above, but I would put my money on this^^



You need to log, then we can be of more help.
Okay so i did get my cable today and i did a little logging prior to reading your posts, with ROM raider are you wanting me to log all of the Knock correction items? I will log and report on the data, im not sure what to look for in that data other than the degrees that it displays.

I appreciate the input!
 

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Discussion Starter #13
It is a bit of a gamble, but I'm thinking maybe the restrictor pill was changed out, the lines still aren't run correctly or are the wrong ID, or the BCS is bad.
I ordered the complete pill and the three hoses with the T-fitting today should be here at the end of the week. I will post info on tonight's log.
 

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Okay so i did get my cable today and i did a little logging prior to reading your posts, with ROM raider are you wanting me to log all of the Knock correction items? I will log and report on the data, im not sure what to look for in that data other than the degrees that it displays.

I appreciate the input!
Don't log anything extra, it increases the time between readings - a log like this would be pretty ideal:
https://docs.google.com/spreadsheet/ccc?authkey=CP7f8o8P&key=0Aj6DxXE1y3erdHNXOEtMQU5Nd0VRUk9lS1FzRHJtekE&hl=en_US&authkey=CP7f8o8P#gid=0

3rd (or fourth) gear WOT 2K-redline. Post it up.
 

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Discussion Starter #16
All of the above, but I would put my money on this^^



You need to log, then we can be of more help.

This is the data that i took tonight. I feel bad being that hard on the car that much. Im not sure what the knock info means, it may be useless but you may understand it. The car still pulls hard so im still leaning towards a leak so something small but then again i dont know. Let me know if there is anymore data or other specifics that would help let me know.


Thanks for all of your help too.
 

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Discussion Starter #17
Logged update

Download and run this - post the screenshot. You don't have to drive anywhere for it, just follow the instructions.

RomRaider • View topic - UTILITY: Learning View (version 0.6a 03-21-09)

click the DTC reader box too just to make sure.

Im sorry for not logging exactly what you had sent in the spreadsheet, I was running some logs at that moment i posted them anyway. See if you can put something together off of it.

Also i have attached the learning view screenshot.

I will run your spreadsheet set up tomorrow night if the data i gave you doesn't suffice.

Thanks a bunch
 

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I have a heck of a time trying to read those as PDFs.

Your learning view looks good - Your fuel trims are reasonable, you have very little learned knock correction to speak of and your DAM is pegged.

Your boost looks like it is actually lower than you said - it is really likely you just have an issue with the boost control system. You are running on wastegate spring pressure only, and the most likely cause is your solenoid isn't bleeding off any pressure, or it isn't in the correct position to pass that on to the wastegate actuator.

Your ECU wants a lot more boost, and reports a big error. Oh, and Mainframe owes me a beer.


BTW, your not even challenging your car. You have a lot more boost coming and it will be a whole different animal then. My stage II 2.0l WRX would destroy your car right now.
 

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Check your map notes to see what the WGDC is (waste gate duty cycle). Often times when a Boost Controller is installed, the tuner reduces, or even completely eliminates (depending on style of tuning and whether BCS is used as well) the WGDC.

The fact that you had the pill in the wrong place, basically says there was a boost controller installed previously.
 

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Whoops... didn't see your PDFs. Doesn't look like the WGDC is set to 0.

Sometimes when a car is returned to stock, the wrong ID vac hose, or the wrong year boost control solenoid is used. That can affect boost as well. Also, if he re-used the hoses that were on there, but pulled off for the boost control solenoid, there could be a crack in one line, or the t-fitting.
 
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