7 Aug
2001
7 Aug
'01
7:11 a.m.
Douglas Quebbeman wrote:
[stuff delete]
But K-Jetronic (CIS) isn't timed at all- every cylinder port is
getting fuel at all times. The fuel distributor controls how much
by the area of the slots exposed int he control plunger as it
moves up and down in response the the motions of the airflow sensor.
But then again, as you and others have observed, CIS debuted later
than I thought... so I don't know as much as I think I do!
-dq
So, prior to the fuel crisis and emission
controls, what was
the motivating factor for the use of EFI?
Cost, weight and reparability. Mechanical injection pumps have to
be mechanically timed to the engine (either gear or belt driven off
the cam), require their own oil supply and return lines, and have
about 973 parts ranging in size from large to itty-bitty. When the
3D cam starts to wear (and it does) it effectively changes the map of
the engine, and anytime you modify the engine in terms of
displacement or compression (or even futz with the exhaust too much)
you have to re-profile that weird 3D cam -- something that requires
taking the pump to bits and having a Really Good Time in a fairly
specialized machine shop.