DIY_EFI Digest V4 #547- throttle and timing

[Clare Snyder]

> >
> >Date: Sun, 26 Sep 1999 00:49:35 EDT
> >From: PHXSYS at aol.com
> >Subject: Typical ignition timing  response to throttle snap?
> >
> >HI everyone
> >
> >I was wondering  what effect rapid throttle movement has on ignition
timing.
> >
> >I know that extra fuel is injected when the throttle is quickly depressed
> to
> >improve throttle response. Are there any ignition timing events that
occur
> at
> >the same time to also improve throttle response?
> >
> >Do you get a little extra advance during TPS event or what?
>
> Not sure about Efi Systems but on a normal dizzys you just have
centrifugal
> (rev related) advance and vac advance (throttle positon/rev related). I
> know that you don't need vac advance, all it does is improve part throttle
> fuel ecconomy. On the Rover Mini Mpi system water temperature is also
taken
> into consideration... It also uses the MAP sensor (equiv of centrifugal)

Pardon?
The MAP sensor reads eqivalent to the Vacuum advance - measuring engine
load.

On a distributor with vac advance. high vacuum advances the timing under low
load for economy. sticking your foot into it drops vacuum, effectively
retarding spark to eliminate ping under load.
A total engine management system would also have to take this into account.


> and the CPS (crank positon sensor) to get the engine speed (centrifugal
> advance). It also uses a cam postions sensor 'to run in sequential fueling
> mode' Is this mode where it learns what fuel it should be putting in from
> the Heated oxygen sensor? Why would it need to know where the cam is to
run
> in the mode? It also measures the actual cam period.... Why does it need
to
> know the actaul cam period?
>
> HTH, Thanx,
>
> Ade
>