need advice (speed density)

PKRWUD · 09-23-2001, 06:39 AM

What am I missing here? The ECM needs a signal from the TPS in order to know what to do. Saying you don't understand why it isn't responsive with the TPS disconnected is like saying "I don't understand why I'm soaking wet", while you're climbing out of the pool. EFI isn't like a carbureted engine. The throttle doesn't work the same way. With a carb, it was appropriately referred to as the gas pedal because as you opened the throttle, the engine vacuum and the air pressure would suck fuel from the carb into the venturi, and give you gas. The throttle forced the fuel. With EFI, there is no gas anywhere near the throttle. In fact, when cranking the engine to start it, if you hit WOT, the fuel will be completely shut off. The ECM controls the fuel delivery, and the only way the ECM knows what the driver is asking for is via the TPS, which, BTW, should NEVER be adjusted above .95VDC at idle. You seem so confident that it should run great without the TPS, that I figure I must have missed some part of this. Please explain it to me.

~Chris

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09-23-2001, 06:39 AM	#7
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	What am I missing here? The ECM needs a signal from the TPS in order to know what to do. Saying you don't understand why it isn't responsive with the TPS disconnected is like saying "I don't understand why I'm soaking wet", while you're climbing out of the pool. EFI isn't like a carbureted engine. The throttle doesn't work the same way. With a carb, it was appropriately referred to as the gas pedal because as you opened the throttle, the engine vacuum and the air pressure would suck fuel from the carb into the venturi, and give you gas. The throttle forced the fuel. With EFI, there is no gas anywhere near the throttle. In fact, when cranking the engine to start it, if you hit WOT, the fuel will be completely shut off. The ECM controls the fuel delivery, and the only way the ECM knows what the driver is asking for is via the TPS, which, BTW, should NEVER be adjusted above .95VDC at idle. You seem so confident that it should run great without the TPS, that I figure I must have missed some part of this. Please explain it to me. ~Chris ------------------ Retired Moderator MustangNet My site: JimPorterRacing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!!