Date: Wed, 29 Nov 2000 10:16:28 GMT From: hohnopsamlid.invalid (Goran Larsson) Subject: Re: What is it?.......
In article <TlXU5.88991$U46.2856253nopsam1.sttls1.wa.home.com>, Code <fourply21nopsamail.com> wrote: > I have 1988 Saab 9000 Turbo (100k miles) and of course have no manuals nor > can I seem to locate any. I'm trying to identify a part. It sits near the > top driver's side of the radiator, there are 3 vacuum hoses attached to it > along with an electrical connector. It is the APC valve. One hose is connected to the input side of the turbo, one to the output side of the turbo, and one to the wastegate on the turbo. The wires are conencted to the APC electronics box. The APC valve is driven by a 12Hz signal from the APC electronics to control the turbo pressure. When air is routed from the output side of the turbo to the wastegate it opens and reduces the turbo pressure by bypassing the compressor part of the turbo. The APC electronics electronics uses this to control the turbo pressure to protect the engine (both by limiting pressure to a preset limit and also reduce it when the engine pings [knocks]). If the electrical connection to the APC valve is removed then the wastegate will open and you will only get basic turbo boost. The performance of the car will be close to a 9000i. If peformance isn't changed by conencting the wires then something is wrong with the APC valve or the APC electronics. -- Göran Larsson Senior Systems Analyst hoh AT approve DOT se
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