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Old 05-21-2008, 12:32 PM   #3 (permalink)
Master EcoModder
Join Date: Apr 2008
Location: Earth
Posts: 303

Pushrod - '02 Chevrolet Cavalier
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It's foolish, like pretty much everything else Chrysler has done.

If they developed their own ECU's, they'd realize that all they need to monitor fuel usage is a little extra code. The ECU already decides how much fuel it injects every cycle, the only thing missing is a routine to track that number.

Of all the parameters that go into determining fuel usage, fuel rail temperature is on the bottom of that list. MAP is only halfway accurate if the engine is at 14.7:1 all the time. That means no injector shutoff, no cold start enrichment, no cylinder deactivation (at least not with open intake valves), no decel lean-out and no WOT. Becoming fixated on one tiny little variable (fuel rail temp) while ignoring everything else that influences fuel usage is penny-wise and pound foolish. Besides, MAP only helps you determine air flow, not fuel flow, and then, only if you have RPM data to go with it!

There's no law against patenting stupidity. Chrysler's (borrowed) money is as green as everyone else's. How about you idiots make something people would buy, like I dunno, an economy car under 3200 lbs without integrated AC outlets and in-dash refrigerators.
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