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Discussion Starter #1 (Edited)
I have a 2005 Saab 9-5 Aero and I am experiencing boost problems. The turbo is spooling up fine and goes slightly into the red at first. The gauge will then fluctuate up and down at the end of the yellow area. Although the gauge is reading i'm getting full boost (for the most part) there is not very much pull to it at all. Also sometimes around 3500-4200 RPMS I will feel the car somewhat hesitate under full throttle.

I have read other boost threads and none are too similar to mine. All I have done is an open air intake. (Which I clean about every 5000 miles)

I have tried the following:

-The bolt mod: http://www.econmancer.com/?p=65
-Bypass Valve hose Mod
-Replacing all vacuum lines
-Replaced Mass Air Flow Sensor
-Checked for other vacuum leaks
-Checking intake piping for leaks
-New Spark Plugs
-New DIC

Problems:

-No pull to the boost
-Boost fluctuating between low red and high yellow
-Throttle seems to cut off around 3500-4200 RPMS sometimes
-P1181 Engine code (reset and yet to come back)
-Hose going from boost pressure control valve to waste gate has super tiny tear

While replacing the Vac lines I accidentally broke this piece:



When it was broken it could either be apart and the car would idle close to stalling, or the part could be taped together and the car would idle at around 1200 RPMS. So I taped the part together to keep the car from stalling and ordered a new one. While the car was idling at 1200 RPMS the boost came on strong, sounded healthy, and ACTUALLY had pull to it.

I then dropped my car off at my local Saab mechanic to get the heat fixed and that small white piece replaced. After picking up my car while driving home I got a check engine light. I went to my local Auto Zone and got my light read for free and got a P1181 code. I reset the code and it hasn't came back sense. (Its only been a few days.)

Does anyone have any advice on what to do, or what could be causing my boost problems??!!

Lastly does anyone have information about the diameter and wall thickness of the hoses attached to Boost Pressure Control Valve? The one running from the second nipple down to the waste gate has a small tear in it, so i'd like to replace it. But can't find any information about it.
 

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It sounds like the bypass valve itself could be bad (the valve on the black plastic CAC tube). Under heavy boost the pressure is blowing it open and releasing boost. It also looks like one of the only things not replaced. The white plastic check valve you broke is for the crankcase ventilation system and if it was leaking then it would cause a vac/boost leak explaining the high idle situation. It could have also bled off enough boost pressure at the time to prevent the bypass valve from fluttering as well. You could pull the bypass valve off to see if it holds vacuum and to see if it blows open easily.

The waste-gate is on the turbo itself and bypasses exhaust gasses and is controlled by the valve you did the bolt mod to. I just use standard vac-hose from the local auto parts store for everything coming off the intake manifold (BPV, CBV and FPR). Or get the silicon stuff on-line (looks like you might have some already?)

My first suggestion would be to replace any vac line that is cracked or leaking and get rid of all that mod stuff. The mods didn't fix anything as you mentioned and you want a control point for diagnosis. Print off a nice schematic of the vac lines (search this forum for some pics) and then go buy 12 feet of vac hose from the parts store and replace it all. Cheap, easy and good assurance you have no leaks. Test the bypass valve or just buy a nice new forged one and be done with it.
 

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Discussion Starter #3
I just ordered a nice forge bypass valve, a new boost control valve (even if mines not faulty the car is ten years old so it's bound to fail at some point), and a Kinugawa adjustable wastegate with a 1.0bar Spring & 1.2bar spring (for when I go Stage II). So we'll see if this stuff helps. I actually did a ton of research and some research led me to an ecu reset. The car used to be driven in a large city so it never really got a chance to be opened up and the ecu accommodated to that. I noticed a great increase in turbo spool after that. (I know I'm not supposed to talk about racing but we were in Mexico ;) ) and went a couple runs against 2011 Gti I previously lost to and dusted him this time around. So the ECU Reset helped a ton. These new parts should help even more. Thanks for your help and knowledge buddy! I'll let you know how it goes.
 

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Yes and no. That is an older set up, not sure what year but pre-06 for sure. The Evap line no longer tees into the turbo inlet but instead loops back around to the back of the throttle body. If that line is on the TB, follow it - on mine it routes over by the fuel lines over to the passenger side fender. There is a port with a green cap in-line with this hose and a check valve, then it makes a 180 degree loop around to the Evap valve buried under the MAF sensor. It then routes back by the same location at the fender and under the car to the Evap canister by the fuel tank. This is an 06 set up but if you don't have the T at the turbo then I can't see it being setup any other way. If the emissions label is still there reference that. Attached is a photo of my label for reference. If you have no check valve or Evap purge valve I would be surprised but that would certainly cause an issue. And if it is setup like this then the bolt mod does nothing.

The fact that an ECU reset "cured" the problem leads me to believe the system is all there and connected correctly. Replacing those parts you mentioned is a good place to start.
 

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Discussion Starter #7
I'm actually slowly starting to lose performance again after ecu reset (boost needle not touching red as it usually does it gets almost to the end of yellow/ occasionally hits red then drops to almost end of yellow). I can hear a loud air sucking noise while spooling it sounds almost like air is being sucked in somewhere it's not supposed to be. I'm about to get under the car and check my IC pipes / intake to make sure it's properly secured. The hooter noise has also returned so my bypass valve is definitely faulty.
 

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Discussion Starter #8
Reset ecu by a.) disconnecting the negative battery terminal b.) unplug the ecu c.) remove fuse f2 (I think) from fuse box next to battery. I couldn't find the right fuse so I pulled all of the fuses in the box next to the battery lol
 

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I couldn't find the right fuse so I pulled all of the fuses in the box next to the battery lol
:roll:

Weather you actually reset the ECU or not, it does not appear that the concern is fixed. Did you take care of the cracked hose you found and verify the proper routing? No sense in further diagnosis until you fix what you know is broken.

I've never personally seen an ECU reset fix anything that wasn't stuck in limp mode. You might "reset" the ECU but it will learn with faulty parts and eventually be back right where it was - kind of like clearing a DTC without fixing the root cause.
 

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Discussion Starter #10
I couldn't find the right fuse so I pulled all of the fuses in the box next to the battery lol


Weather you actually reset the ECU or not, it does not appear that the concern is fixed. Did you take care of the cracked hose you found and verify the proper routing? No sense in further diagnosis until you fix what you know is broken.

I've never personally seen an ECU reset fix anything that wasn't stuck in limp mode. You might "reset" the ECU but it will learn with faulty parts and eventually be back right where it was - kind of like clearing a DTC without fixing the root cause.
The hose has the tiniest rip in it I don't think it could affect very much but then again who knows. It's the second hose on the boost control valve that leads the wastegate. And I plan on purchasing these parts anyways wether they fix the problems or not.

The tear is shown below. Does anyone know the size of these hoses so I can go buy a new one? They have a larger hole then the normal 4mm vacuum hoses. And have a larger outside wall.
 

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change those red plastic rings/valves in picture (one ar the top of TB pipe and second in intake manifold.

Try swapping TB..
 

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Discussion Starter #13
change those red plastic rings/valves in picture (one ar the top of TB pipe and second in intake manifold.

Try swapping TB..
I checked my throttle body, took it out, cleaned it checked for stripped wires, etc. From what i can see the throttle body is still in good condition. I'm no mechanic though.
 

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You can not say TB is in good working condition by how clean it is.

TB has mechanical and electrical part. In most of the cases problem is in electrical part.
 
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