Adjusting Idle Without Catalytic Converter - Porsche 928 Workshop Manual

24
Electronic Fuel Injection - LH-Jetronic
928
ADJUSTING IDLE WITHOUT CATALYTIC CONVERTER
87 MODELS ONWARD
2.Reconnect air intake hose
ENGINE TYPE M28. 41/42
3.Run en ine to operating temper-
ature 9 70-90X oil temperature).
Note:
Use oil temperature meter,
special tool 9122 +9122/2.
No provision is made for adjusting
the idle speed. The adjustment at
the throttle nozzle is no longer
Jlecessary-;
Idle Speed co-
Level Adjustment
---.-_
_--^ -". -~_l___l_-.--
Precondition for adjustment:
Engine in perfect mechanical order.
Switch off all consumers during
adjustment. Make adjustments as
quickly as possible to avoid
excessive heat at intake ports
which would result in incorrect CO
readings. Intake air temperature 15
- 35OC.
l.Disconnect additional air pump
hose at changeover valve and seal
changeover valve with a suitable
plug.
4.Check CO-level. If the CO-level
is not within specified limits,
correct setting of CO-poten-
tiometer. Remove plug covering
hole which provides access to
CO-adjustment.
Specified CO-value:
Turning clockwise =
-
0.5 - 1.5%
richer mixture
Turning anticlockwise = leaner
mixture
a
24 - 214
Adjusting Idle Without Catalytic
Converter
Printed in Germany