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Re: What went wrong??? Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Mon, 8 Jul 2002 10:15:59 In Reply to: Re: What went wrong???, Saabiesaab, Mon, 8 Jul 2002 03:18:40 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I'm not sure about the details of retrofitting an old DI into a car wired for a newer DI. I would stick with newer. DI's die, and in my mind, an older one is that much closer to death than a newer one.
As to why only under boost - a few reasons-
First, the higher the pressure in the cylinder, the harder it is to make a spark jump. That's just physics. Under boost, the cylinder pressures are higher. If the DI is putting out weak spark, the spark may be able to jump under non-boost pressures, but can't jump under boost. No spark, and the engine stumbles.
Second, the DI uses the spark plug as a knock sensor. There is no other knock sensor in the engine. The Trionic adapts to knock by changing spark timing and adjusting boost. The way the DI senses knock is by measuring the resistance of the combustion by-products in the cylinder after combustion. If the spark plug is wrong or the DI is going south, it may be mis-identifying knock, scheduling the wrong ignition timing, etc.
posted by 140.157.4...
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