Subject: Re: 034 EFI

[Orin Eman]

>
> > As with any EFI system, 034efi can be configured with a hall sender on the
> > crank too by mounting a hall sender to read off the crank.  It is up to the
> > installer how much effort they would like to put into the installation to
> > effect certain advantages.
>
> How would this work?  Don't you need a signal that represents the top of the
> compression stroke for each cylinder?  Unless I'm mistaken I don't think you
> can get that from the crank since you'll be getting the top of the exhaust
> stroke too.  Don't want to be firing those injectors then.. unless you want
> some jet propulsion as well ;-)

Except at low RPM (ie. idle), when you can get slightly lower
emissions by timing the injection to a certain point in the cycle,
it doesn't really matter when the injectors are fired.  Remember they
fire at the back of the intake valve, not into the chamber itself.
In fact, when developing high power, the injectors are likely to be
on 85% or more of the time.  To make things easy in the ECU, the injectors
often are fired all at once - known as batch mode.  Thus each cylinder gets
its injector fired at a different point in its cycle.

When using a crank sensor, if you want to determine compression/exhaust
stroke, some kind of cam linked sensor is required.  On the MC and 3B
engines, it's a hall sensor in the distributor with one window
centered 62 degrees BTDC on Cyl 1.

For timing fuel injection, it is simply unnecessary to time the injection
accurately unless you are trying for that last little reduction
in emissions... not a concern of the 034efi system.

Orin.