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Discussion Starter #1
Hi, if anyone could offer any assistance then that would be very much appreciated. The age old problem Im sure, but my Abbott-tuned (ECU, intercooler and exhaust) 03 HOT isnt boosting properly.:cry: I bought the car on saturday and it ran amazingly for 250 miles, boosting into the red, but since intermittently half way into yellow, come off the gas and acelerate again and it will produce a bit more but not into red and feels slightly hesitant, a little 'choked-up' and so on. I phoned Abbott and they were their usual unhelpful selves :( - wouldnt even discuss possible avenues for me to explore and I can't make a 400+mile return journey to have them empty my wallet just to diagnose. I acept that it may well have to go on a rolling road locally, but if you have any ideas then it would get me/a tuner off to a start.
Many thanks
Martyn
 

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Sorry to hear your whoes on such a new car to you.

Try checking replacing the following components
-Check all the vacuum hoses are on tightly, there are lots of them, they do go hard and break sometimes
- Boost control valve that sits above the 'cobra' pipe - if its broken you will get funny boost spikes
-Check plugs are clean
-Borrow another DI cassette and try this as well
- Make sure the turbo delivery pipe is onto the throttle body properly
- Is your Bosch dump valve performing properly?

Thats a good start for you - hope you get to the bottom of it soon.
P
 

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Do the checks as posted above, but also, you must remember that the boost guage in a 9-5 Aero is not a real vacuum boost guage, it's an electronic 'torque request meter'.
 

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Here's an easy mod that has fixed many people's boost issues...

Attached to the top of the Cobra is your bypass control valve. Remove the top 6mm vacuum line and jam a pen or screw into it temporarily, then try driving the car again.

If it feels responsive again, you can make this modification permanent by buying a two-way vacuum line splitter. Follow down the vacuum line that you just plugged, and there will be a three-way splitter branching off into the cobra and towards the back of the engine. Now remove the vacuum line that used to feed out from the bypass control valve, and replace the three-way connector with the two-way one.

Basically that vacuum line that goes to the back of the engine has a check valve that can go bad and let pressure force against the outlet of the bypass control valve. Because of this, the valve can't properly vent boost going to your wastegate, and so the car can't hit higher boost levels.

Vacuum lines are very important for maintaining correct boost pressures. On my 99 I found a few of them rotten, so I replaced all of my lines. Just follow the line on the bypass valve towards the back of the engine; from there replacing them one at a time until you've done them all.
 

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aeropilot said:
Do the checks as posted above, but also, you must remember that the boost guage in a 9-5 Aero is not a real vacuum boost guage, it's an electronic 'torque request meter'.
Are we sure about this? I have heard this many times but it doesn't make sense to me. There is a MAP signal on the CAN bus... which is connected to the instrument cluster. Why would they simulate a signal that they already have available?

It might not be a proper vac/boost gauge with numbers, but I would be surprised if it isn't a real boost gauge. You can even set the sensitivity of it (i.e. what pressure the "red" zone begins at) via Tech2. Why would they have this option if it was a BS meter?
 

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stipud said:
Are we sure about this? I have heard this many times but it doesn't make sense to me. There is a MAP signal on the CAN bus... which is connected to the instrument cluster. Why would they simulate a signal that they already have available?

It might not be a proper vac/boost gauge with numbers, but I would be surprised if it isn't a real boost gauge. You can even set the sensitivity of it (i.e. what pressure the "red" zone begins at) via Tech2. Why would they have this option if it was a BS meter?
There is a thread were somebody is interchanging the LPT instrument cluster with another (with the BS turbo gauge). He is using TECHII to mary that unit to te car, resulting in a properly working boost gauge. I asked him what he would use to feed this gauge, he told me that the information for the gauge comes from the ECU. So.... it seems to be an indirect BS meter.

Arnie
 

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Discussion Starter #7 (Edited)
As always, a heart-felt thanks for your thoughts so far.:D The car is booked for the Rolling Road on tuesday just in case I can't trace the fault using the ideas that you have posted. Naff weather today has prevented me from having a look myself, but I will start working through the suggestions bit by bit. Im intrigued if anybody has a response to the last post...?
 

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Arnie said:
I asked him what he would use to feed this gauge, he told me that the information for the gauge comes from the ECU. So.... it seems to be an indirect BS meter.
The ECU has a real manifold air pressure signal. Using a scan tool, I have monitored the MAP signal and compared it to my aftermarket boost gauge... they were identical. If the instrument cluster uses the MAP signal from the ECU, then it is a "real" boost gauge, not a fake meter.

I wouldn't mind installing the stock boost gauge in my car. Wonder if it is possible in a 99...
 

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stipud said:
The ECU has a real manifold air pressure signal. Using a scan tool, I have monitored the MAP signal and compared it to my aftermarket boost gauge... they were identical. If the instrument cluster uses the MAP signal from the ECU, then it is a "real" boost gauge, not a fake meter.

I wouldn't mind installing the stock boost gauge in my car. Wonder if it is possible in a 99...
I assume you just have to get hold of the proper instrument cluster.

Arnie
 

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aeroT16 said:
As alway, a heart-flet thanks for your thoughts so far.:D The car is booked for the Rolling Road on tuesday just in case I can't trace the fault using the ideas that you have posted. Naff weather today has prevented me from having a look myself, but I will start working through the suggestions bit by bit. Im intrigued if anybody has a response to the last post...?
I wouldnt put a Saab with a problem on a Rolling Road :nono;

Well not unless it was a Saab specialist's rolling road.

The car has a problem so why let someone with little or no saab knowledge rev the nuts off it to give you some figures that tell you the car has a problem :confused:

Everyone here has car problems, thats why we came to the fourms, but no one has used a RR to fix them as far as I know - lets say its running lean or has a missfire - you wanna take that to 6500 rpms :eek:

Find a decent saab indie and get a proper diagnosis - I can assure you it will be a hardware problem - not a software one.
 

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Discussion Starter #11
That does make a lot of sense, I know what you're saying. The only reason I was thinking of a session on the rollers was as a last resort incase it was a problem with the air flow meter or something like that - something beyond my expertese or diagnostic powers! Its the intermittent nature and 'choked up' feeling (like a cloth up the exhaust pipe) that makes me think its not a split/loose vac pipe or something... The next logical question then - does anyone know of a Saab wizzard in the middlesbrough-ish area that I could turn to to have a nosey under the bonnet for me?!;)
 

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Turbo Gauge - from the WIS

I don't know what "mg air mass/consumption" means but it doesn't sound like the pressure inside the intake manifold...
The main instrument unit is fitted with an electronic boost gauge.

The gauge is driven by a stepper motor which is controlled by the main instrument control module.

The value shown by the boost gauge needle is based on the following: Trionic calculates the mg air mass/consumption and converts this information to a value between 0 and 255. Trionic sends this as a bus message "boost gauge". This value corresponds quite well to the engine torque. The main instrument unit uses this value for the boost gauge needle which shows the driver the load on the engine.
 

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After my recent experience which left the car jumpy and not boosting I would get your intake manifold MAP sensor checked. Along with the other previously suggested possible sources of the problem.
 

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I would definately try to plug the hose that connects to the top connection on the three way valve thingy at the front of the engine - Im sure that is the problem. Mine never used to boost in the red and I used to feel that the car felt held back (I though the ESP was being over-cautious). Now I have red boost and it is a completely different car to drive!

Its free to block the pipe, so please try it first.:cheesy:
 
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