19 Mar
2001
19 Mar
'01
9:49 a.m.
[Bosch FI stuff, deleted]
Joe wrote:
On Mon, 19 Mar 2001, Chris Kennedy wrote:
Cool! It IS a computer. The injectors were
pulse width modulated.
Somewhere I have the manual for that thing. My mother had a '70 VW type
III
> with that system and it ran great. I suppose it is -- although the one being described
(L-Jetronic) is an
analog
one comprised basically of a variable duty cycle oscillator. In many ways
it's
like an electronic version of K-Jetronic; all the injectors fire at once
with
no synchronization with the cam and duty cycle controlled by a set of
variable
resistors (one on the airflow sensor [which was _not_ a MAF]), one for
engine
temp and (only on some) one for ambient temp)
1) The lack of synchronization made it possible that one time that we
needed to move a car (only a few miles), one fellow drove while I sat in
the open rear hatch rapidly making and breaking a bare wire contact.
2) The system was configured for 1600cc. One fellow (in La Honda, next
door to Jim Warren) was able to get surprisingly acceptable performance
with 2180cc (in a '63 VW pickup!!) by connecting a pot to the head
temperature sensor.
3) For most mechanics who dealt with it, it was their first experience
with electronics more complicated than points and condenser. A friend of
mine got a car for a few hundred dollars that the dealer had given up
on. Turns out that one bad cell, plus one weak cell, in the battery was
sufficient to bring the voltage down too low for the FI, while still
cranking well enough that the dealer mechanics could not accept that the
weak battery could be the problem.
4) I never saw it, so it qualifies as FOAF: a number of the control
units were destroyed by the baking booths in paint shops! And just
imagine trying to convince the owner of the paint shop that your engine
problems were caused by his paint job!
--
Grumpy Ol' Fred cisin(a)xenosoft.com