K-Jetronic with lambda oscillations

[pietro barabaschi]

Hello, i'm new to the mailing list therefore please excuse me if i make a
question which has been already treated in the past.

I have a ferrari308QV which runs with a K-Jetronic with lambda fuel
injection system. the problem i notice is that when the lambda is connected
(with the computer in closed loop) the air/fuel mixture is oscillating
resulting in a corresponding oscillation of the engine speed.

at first i though that the sensor was gone. changed the sensor: nothing
changes.

measuring the voltage at the sensor i see that it jumps between lean and
rich rapidly with a peiod of ~1s. the frequency valve correspondingly
follows. the problem goes away when i disconnect the sensor and the
computer goes in open-loop automatically.

one of the problems is that i have no real technical book that describes
the controller employed by the system. i can only assume that it is a PI
controller but i do not know is the controller is completely digital or if
there's an analog part as well.

now the questions:

-does anybody know what may be faulty?
-any bosch technical literature on the K-Jetronic computer? if yes where
can i find it.
-is it possible to change the control gains in the K-Jetronic?

I appreciate any response . regards.

Pietro


Pietro Barabaschi

ITER-San Diego JWS
11025 N.Torrey Pines Rd.- LA JOLLA-CA 92037
USA
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