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Old 08-26-2004, 08:51 PM   #11 (permalink)
Fred W.
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Default Re: APC problem, Saab 9000CS lpt Bucking under boost


"Anthony Cooke" <ant7t5@tiscali.co.uk> wrote in message
news:407d1dae$1_1@mk-nntp-2.news.uk.tiscali.com...
> Hello, I have just bought a 1996 9000 CS eco. It's my first Saab and I

think
> it's great.
>
> It is running fine under normal conditions but when I go to overtake

the
> fuel cuts out as soon as the turbo kicks in. Someone has suggested that an
> APC Solenoid or control box has gone bad and is protecting the engine when
> it doesn't need to. The problem starts at around 3500 revs but only if I'm
> heavy footed.


There is a lot more to it than that...

Where is the boost gauge when the cut-out happens? Is it way up in the
middle of the red? If so, that is where the overpressure switch is supposed
to shutdown the engine by cutting spark. If it is low red or orange then
the switch may be faulty. It is mounted on the right side firewall.

The turbo is easily capable of making too much boost pressure which has to
be limited based on engine running conditions to prevent destroying the
engine. The control box (APC) has the job of monitoring engine running
conditions and sending the electrical signal to the APC solenoid. The APC
solenoid's job is to modulate the vacuum going to the wategate control
dashpot. The wastegate controls the boost pressure by dumping excess
pressure when opened.

If you were to unplug the electrical connection to the APC solenoid it
should route all of the vacuum to the wastegate dashpot and drop to "base
boost" only, which should be near the middle of the center orange section of
the boost gauge. This mode is actually quite driveable though you will have
less maximum power.

If you still get too much boost then either the APC solenoid is stuck closed
(actuated) or the wastegate is stuck closed (won't dump pressure).

I would suggest looking at this web site which goes through troubleshooting
the APC system quite well, though it may be a bit too technical for the
average handy-Joe.
http://68.18.142.57/turbo_folder/baseboostdia.htm

Good Luck,
-Fred W



 
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Old 08-26-2004, 08:51 PM   #12 (permalink)
tCowjww
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Default Re: APC problem, Saab 9000CS lpt Bucking under boost

"Fred W." <Fred.Wills@allspam myrealbox.com> wrote in message
news:QbKdneo6NL7_ruDdRVn-hA@adelphia.com...
>
> "Anthony Cooke" <ant7t5@tiscali.co.uk> wrote in message
> news:407d1dae$1_1@mk-nntp-2.news.uk.tiscali.com...
> > Hello, I have just bought a 1996 9000 CS eco. It's my first Saab and I

> think
> > it's great.
> >
> > It is running fine under normal conditions but when I go to overtake

> the
> > fuel cuts out as soon as the turbo kicks in

>
> There is a lot more to it than that...
>
> Where is the boost gauge when the cut-out happens? Is it way up in the
> middle of the red?


I didn't think the 9000 LPT models had a boost gauge :-/


 
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Old 08-26-2004, 08:51 PM   #13 (permalink)
Anthony Cooke
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Posts: n/a
Default Re: APC problem, Saab 9000CS lpt Bucking under boost

You're right Fred, it doesn't have a boost gauge. It seems to cut out with a
jolt as soon as I feel the extra power from the turbo spinning up. It feels
like a rev limiter kicking in.

"tCowjww" <tcowjww@trousers.yahoo.co.uk> wrote in message
news:c5jg78$lh1$1$830fa17d@news.demon.co.uk...
> "Fred W." <Fred.Wills@allspam myrealbox.com> wrote in message
> news:QbKdneo6NL7_ruDdRVn-hA@adelphia.com...
> >
> > "Anthony Cooke" <ant7t5@tiscali.co.uk> wrote in message
> > news:407d1dae$1_1@mk-nntp-2.news.uk.tiscali.com...
> > > Hello, I have just bought a 1996 9000 CS eco. It's my first Saab and I

> > think
> > > it's great.
> > >
> > > It is running fine under normal conditions but when I go to overtake


> > the
> > > fuel cuts out as soon as the turbo kicks in

> >
> > There is a lot more to it than that...
> >
> > Where is the boost gauge when the cut-out happens? Is it way up in the
> > middle of the red?

>
> I didn't think the 9000 LPT models had a boost gauge :-/
>
>



 
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Old 10-26-2004, 04:01 AM   #14 (permalink)
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Join Date: Oct 2004
Posts: 1
Default same problem apc bucking under boost please help 1989 saab 9000 turbo.

Hi my name is james young im from michigan i have gotten a saab 9000 turbo and called the deler and they told me my mass air senser was bad so i got one of those and it didnt help. im desprate i need it fixed and im 17 with little money. mine meets the discription of this mans problem but i d0ont no what you mean about apc or waste gate i need to fix this my self i lose power when i put the pedle to the floor and its like its not getting gas and it bucks also. can u please help i really need it thanx. we didnt no what it was i got new spark plug wires a new distributer and router i got a new filter my dad thinks saabs suck now and i love the car help me fix it and prove him wrong please?
estakin
James young
estakin is offline  
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