Low Turbo Boost - Mid Yellow Only

[shayreddy]

OK - fellow saabers I am going crazy ... Can anyone tell me what a 2000 95 aero, no sludge, well maintained car should feel like - The only mod is a k n n filter , closed.

Eveyrone at the traffic light zips by me..? This car is way slower than my 330 i.. Off the line I expected that, but even in 3/4/5 gears? I though this car could take a Porsche???

Anyway I dont think I am getting full boost.the saab gurus dont know what it is... the stealership told me its fine.. But Ther eis no way in hell this car can be boosting fully. I pulled off one the line and drove it ..and for the first time I felt TURBO in this saab. ...

Dumpvalve,apc, vaccum everything checks out fine ... still it has sluggish performance ... No one seems to know whats wrong with this car..

HELP HELP HELP

[Chris 9-5]

Have you read the three other current low boost threads?

[shayreddy]

Originally Posted by Chris 9-5

Have you read the three other current low boost threads?

Yes I have but it seems like there is no one with the same issue. On my car everyhting checks out OK. Just cant identify the problem. I have been reading 1000s of posts ... on many websites... about to give up on this car.

[Chris 9-5]

You said the guages dropped and the ACC went off didnt you?

If you are convinced its power/boost related what have you checked / swapped out?

[shayreddy]

Tommy Turbo of Columbus checked it out and is helping me with it ..told me I am primarly getting engine poweer only and hardley any boost..

So he sawpped some partss with his car which is boosting well... and we did some swap and install tests.

BOV/Bosch valve,
APC solenoid (one with three hoses on it..right?)
Pressure switch

All three were swapped and tested with no improvement of any sorts. All three worked fine on the donor car as well.

Now on using the tech 2 the valve near the firewall clicked .. so that was the test to ensure it was working.

ALso when one pipe was detached from the turbo (wastegate pipe - i belive) The turbo boosted all the wy intothe red and for the first time I felt SAAB POWER.

So I dont know what the issue is, It also doest seem to hold boost pressure
I am thinking of installing a boost gauge so I can monitor more closely.

Dealer checked it out and said ... the fllowing ..
ENGINE had 60KPA boost and tourque output at 280 Nm peak output (Isntaht that low for an aero? I think he gave me a stadrad 2.3T valuethere...)

AARG H... I dont know if this car is fast or slow What shold a 95 aero really feel like ? ..!!!! (230 hp)

[Chris 9-5]

Enough air mass? Check swap AMM?

Spark and DI - check / swap?

Check base boost?

Originally Posted by shayreddy

AARG H... I dont know if this car is fast or slow What shold a 95 aero really feel like ? ..!!!! (230 hp)

Dunno sorry, I have the weedy 2.0

[Chris 9-5]

Ok here is one to try!

The Boost control valve has three pipes coming off it!

Remove the top one, and plug the pipe with a bolt.

Try the car now............



It could be a bad fuel evap system valve

Originally Posted by SectorNine50

Okay I figure I'm going to explain, in detail, how this system works and why it causes boost problems. I even have a pretty picture!



Alright, so as you can see I've circled the check valves that fail. These one-way valves make it so that the vacuum from the throttlebody at lower power levels pulling air from the intake cobra. It also keeps pressurized air from the throttle body from escaping and going back before the turbo since the cobra is at negative pressure from the turbo sucking in air at a rapid rate at high power scenarios. Having the check valves set-up the way they are allows the EVAP system to purge when the engine is vacuuming or boosting.

Anyway, what happens is when the top check valve fails, it allows the charged air from the throttle body (when turbo is boosting) to flow the wrong way through the EVAP purge system's tubes. This pressure flows down through the lower check valve (doesn't matter whether it's good or bad) and runs into the intake cobra and to our boost control valve through that "T." That pressure then pushes open a switch inside the BCV that is meant to resist vacuum (or pressure from inside the BCV) and is controlled by the ECU. After that pressure runs into our BCV and out through the wastegate nipple (combining with another charged air vacuum line which is the bottom nipple) and causes the wastegate to open prematurely.

When the wastegate opens, exhaust gasses bypass the hot-side turbine inside the turbo and in return, the turbo slows down. Because it is opened prematurely, the turbo never has a chance to create full boost, and the turbo gauge reflects that.

My guess is that the reason the top one-way valve fails is because it is under a lot of pressure under WOT, and then straight to vacuum when off the throttle. This is constantly happening even in normal driving conditions. The bottom one-way valve probably lasts much longer because it never sees nearly the same amount of pressure either way.

It is perfectly okay to run the car without replacing that top check valve as the purge system will still operate correctly with one correctly operating valve. However, there is probably minimal performance loss as the pressure inside the throttle body will always be bleeding back into the intake cobra. However, on a stock tune the turbo will be able to compensate for the minor loss. People with aftermarket tunes may like to replace the valves because as we all know, any little bit of boost helps in the higher RPMs when the TD-04 can't hold 21 psi.

If there are any inaccuracies, please post. Hope this helps you guys understand what's going on with this "fix."

[shayreddy]

Yeah ... I am going to check DI and see if the plugs are burnt - they were replace aboubt 10K miles ago....and so was the DI from the dealer .

ALs - can it be that there is a leak near the MAF ??

MAF is the only thing that I really didnt check , or it could be an exhaust issue. THe car feels somewhat strained - like a caged tiger... I also never hear any of the cool sounds these people are talking about . I dont have a forge BOV, all I cna hear is some sucking of the KnN filter thats all ..

Anyway ....how do yo ucheck the MAF ? I am assuming that what the AMM is right ?

[Chris 9-5]

Originally Posted by shayreddy

Anyway ....how do yo ucheck the MAF ? I am assuming that what the AMM is right ?

Tech 2 can check your MAF readings! A leak would give a check engine light on the dash!

Try the pipe thing I just posted

[shayreddy]

OK GONNA GO TRY NOW .. be back in a BIT

[Chris 9-5]

Leave the pipe on the valve open but block the pipe you take off!

[shayreddy]

SIR SAAB ,

YOU ARE THE GREATEST !!!!! THANK YOU - I FELT TORQUE STEER FOR THE FIRST TIME.I LOVE THIS CAR NOW !!! FINALLY .... I cnat wait to let her RIP ON THE HIGHWAY THIS AFTERNOON ..

I STUCK A PEN INSTEAD OF A BOLT CAUSE THATS ALL I CAN FIND... IHOPE THE INK DOENST GET SUCKED OUTOF HTE PEN INTO THE TURBO ...

SO WHAT' S STEP 2 TO MKAE THIS PERMANENT..... ???

[Chris 9-5]

Ha!

I just need to stand up and dance around my PC

Yep thread a bolt into the end, like in my pic and zip tie it away!



Then forget all about it, mine just fine at 350+ bhp

Summit to do with the carbon filter evap canister on the fuel system thingy - you had not much more than base boost only

[shayreddy]

SO what does this mean ?

[Chris 9-5]

Originally Posted by shayreddy

SO what does this mean ?

It means you fixed it - go drive the thing fella

Summit to do with the carbon filter evap canister on the fuel system thingy - you had not much more than base boost only - just block it and forget it

[fusionrx]

Since you have such nice pics of the engine bay, where is the Evap Purge Valve, I am having issues with mine and need to clean/hammer it to get it working again... Eventually I will replace it...

[Chris 9-5]

Originally Posted by fusionrx

Since you have such nice pics of the engine bay, where is the Evap Purge Valve, I am having issues with mine and need to clean/hammer it to get it working again... Eventually I will replace it...

No idea

Sorry.........

[fusionrx]

I gather it may also be known as the charcoal canister...


Got a 0455 error code, replaced gas cap so other option short of hoses is the evap purge valve (charcoal canister). Other folks on TSN said a shot of Carb cleaner in the purge valve/charcoal canister will help isolate if this is the culprit...

[Chris 9-5]

Its inside the inner wheel arch cover on the driver side (UK) of the car

[Al's Red Wagon]

This looks incredibly interesting...

1.) Is this something just moded cars should look into, or should we all try this?

2.) Any pictures of just a regular engine bay doing this? The difference between Chris's and other engine bay's is like the difference between Angelina Jolie and most other women...

3.) You think state inspections with enviro evap tests will care about this?

Thanks