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Discussion Starter · #1 ·
Good morning all,

I have just joined the forum so hello to you all. Due to a Friday night purchase on ebay I now have 2 Saabs so I guess I am a bit of a fan... the 900 I bought has faults which I knew about but unfortunately the 9000 has just developed a fault (more about that in the 9000 tech forum).

Anyway, onto the 900 - it is a T16 2 door, Aero I was lead to believe but not entirely sure about that bit, perhaps someone can identify it properly... the main problem is that when you floor the accelerator, the turbo spools up ok (but slightly underwhelming accleration compared to the 9K) and the gauge sits firmly in the yellow and then when it gets to about 3500rpm it takes off like a cat with a firework up its behind - it is quite brutal and then it overboosts and the car bucks as if the fuel has been cut off.

Any ideas what this might be?

Many thanks in advance,
Anthony
 

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The boost kicking in at around 3000 rpm was characteristic of the Garrett turbos - the later Mitsubishi ones came in at much lower revs and with less of a bang. But I'd have thought that you had a Mitsubishi on an '89. Someone's been messing around with it, by the sounds of it. I would guess they've shortened the wastegate drastically and tweaked the APC pots at random, so boost is coming in too late, too hard, and you are then hitting the overboost/fuel cut. It's easier if you revert it back to stock and then turn it up if you want to. First thing I'd do is a full service anyway, plugs, leads, rotor arm, dizzy cap, as any one of these can give you running problems. Check carefully for vacuum leaks. Then you need to set base boost. This should be half what you intend peak boost to be - leaving it stock for now it would be between 5 and 6 psi. There's a coupel of links here on how to do it:

http://www.thesaabsite.com/Base Boost adjustment.html
http://www.thesaabsite.com/APCadjustment.htm

Have a look on www.900aero.com in the Tech section about APC units.

Welcome to Saab Central :cool:
 

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Discussion Starter · #3 ·
Thanks for that - I would be surprised if someone had been messing about with the APC... the guy that I bought it off had owned it for 6 years and had it all main dealer serviced, just didnt seem to be the type to 'fiddle'. Will check for leaks first and then see where we go.

Thanks once again..
Anthony
 
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