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Stampedetrail · Joined: 29 May 2005 Posts: 274 Location: Fairbanks, Alaska

Well, last weekend after having it sitting around not able to start for two weeks, I pulled all the plugs & cleaned them up thoroughly with sand paper & WD-40. I adjusted the valves cold with a 3mm allen wrench to the specs in my destroyed shop manual. Started right up! Plugs (Autolite) were badly fouled, both oil and carbon, so I switched to a slightly hotter NGK plug and leaned the mixture 1/4 turn with a 3 mm allen wrench the next day. Guess what? No cold start issues ( besides clearing oil for a few seconds ) , no leaking new injectors, just a mean screaming banshee type of noise and pure torque. So I laid in a year's supply of standard Bosch plugs, plus I could use the cleaned up Autolites if necessary. And that same day I spotted a very nice mid-80's 944.
I guess I was surprised that the car would eat up sparkplugs so fast, I've never given them another thought on other (American) vehicles, but I suppose a rich mixture coupled with oil-fouling did that. It's much smoother & quieter now with the valve lash adjusted. Still needs a rebuild of course but for now, mission accomplished.
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1977.5 924 "Martini" head / New Old Stock rebuild
1985.5 944 Why? Because I can.

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

Sounds like you did everything right, there. Well done!

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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org

Stampedetrail · Joined: 29 May 2005 Posts: 274 Location: Fairbanks, Alaska

Thanks, its kind of trial-and-error -- effective but not necessarily brilliant. And not entirely effective, as there's still some excess cold-start cranking. But maybe a good tip to avoid buying a lot of expensive equipment to tune the mixture would be to analyze the spark plugs. I checked them yesterday after all day hard driving-- clean & bone dry, possibly a little hot-- blue around the edges, so I cranked the mixture a tiny smidge richer, and on it goes.
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1977.5 924 "Martini" head / New Old Stock rebuild
1985.5 944 Why? Because I can.