Date: Sat, 10 Mar 2001 17:22:26 +0100
From: guess <vem_tror_dunopsamail.com>
Subject: Re: Noisy Engine & Poor Turbo Performance (1988 900 Turbo 8V)


On Mon, 05 Mar 2001 22:41:51 +0000, Paul Halliday <paul.hallidaynopsameonline.net> wrote: >Given that it is an older car and the temperature here in the north of >Britain is quite cold at the moment (0-5 degrees C), I start my engine and >give it about 1500-2000 RPM for 30-60 seconds before engaging the gears and >driving off. Start driving directly, i donĄt think itĄs such a goo idea to race a cold engine. >Upon driving off, the turbo pressure on the APC gauge will not go into >turbo-charged conditions until the engine has sufficiently warmed up - I >understand this to be the normal condition for driving with a cold engine, >so I am quite encouraged that the engine is protecting itself correcly and >take it easy for the first mile or so. There is no such system on any SAAB turbo, if you would like to, you should be able to ge full pressure directly (keeping in mind that the engine is not warmed up, itĄs not a good idea to to so). >However, when the temperature needle reaches (exactly) the lower end of the >green part of the temperature gauge, a loud whirring starts up in the engine >very intermittently to start with which does cause some considerable >performance drop and the car almost stalls following some pretty sharp >jerks. > >The whirring I mention gradually increases to a constant pitch (about 2-3 >ticks per second) and will remain doing that for the duration of the >journey. Do note that this is not a high pitch whine which I would expect >from an old/dying turbocharger but sounds more electrical, like some sort of >starter motor continuing to fire up. The engine temperature rises to about >half way up the green part of the gauge within a minute or two after the >whirring has reached a constant rate. The whirrig could be caused by the APC valve, located above the radiator, that would explain why you donĄt get any boost either. The stalling iĄm not sure if, could be a lot of things, you should have a traind SAAB tech to take a look at your car. >I have just had the car looked over by a mechanic who has performed pressure >checks on the oil, cooling system and vacuum system and informs me that >there are no problems. Can we rule the obvious out, or are there other >quirks to check out here? That is good, than there should not be a problem with the cylinderhead gasket (that is expensive !!) >Any help will be greatly appreciated ... something I can point my otherwise >fairly nonchalent mechanic towards. Check the ignition system, use the right sparkplugs (known fact: SAAB turbos prefer NGK spark plugs, donĄt use other brands). Check the APC system and the overpressure switch (cuts fuel pump if pressure get to high, could explain the stalling, it might be cutting in to early). /Ma

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