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diesel_john · 05-21-2008, 01:09 AM

Injectors factoids

Throttle Body Injection (TBI) is not always timed to every other revolution of the engine.

Most domestic OE production EFI systems use an ECU with 12 volt Saturated Circuit drivers.
An injector operating on a saturated circuit driver typically has a reaction time of 1 milliseconds.

(Saturated Circuit Driver) Injectors are 10 to 16 ohms for identification purposes.

The very conservative approach Ford uses to calculate the injector size for the factory engine uses the O.E. typically safe 0.80 duty cycle limit.

So a 19 lb/hr Ford rating is at 80% duty cycle.

Some Muti Port Injection (MPI) use:
batch fire,
some use bank fire,
some use individual or sequencial fire. These all fire every other revolution.

But almost all (MPI) are timed to the engine.
I say almost because Chevy has a CPI Vortex V6 and i don't know how it works. It looks like one injector with 6 nozzles.

05-21-2008, 01:09 AM	#116 (permalink)
diesel_john MP$ Join Date: Jan 2008 Location: SW Ohio Posts: 595 Thanks: 5 Thanked 19 Times in 14 Posts	Injectors factoids Throttle Body Injection (TBI) is not always timed to every other revolution of the engine. Most domestic OE production EFI systems use an ECU with 12 volt Saturated Circuit drivers. An injector operating on a saturated circuit driver typically has a reaction time of 1 milliseconds. (Saturated Circuit Driver) Injectors are 10 to 16 ohms for identification purposes. The very conservative approach Ford uses to calculate the injector size for the factory engine uses the O.E. typically safe 0.80 duty cycle limit. So a 19 lb/hr Ford rating is at 80% duty cycle. Some Muti Port Injection (MPI) use: batch fire, some use bank fire, some use individual or sequencial fire. These all fire every other revolution. But almost all (MPI) are timed to the engine. I say almost because Chevy has a CPI Vortex V6 and i don't know how it works. It looks like one injector with 6 nozzles. Last edited by diesel_john; 06-16-2008 at 10:45 AM.. Reason: changed:Throttle Body Injection (TBI) is not always timed to every other revolution of the engine.