catalytic converter BMW 735i 2001 E38 M62TU Engine Workshop Manual
[x] Cancel search | Manufacturer: BMW, Model Year: 2001, Model line: 735i, Model: BMW 735i 2001 E38Pages: 37, PDF Size: 3.9 MB
Page 28 of 37
![BMW 735i 2001 E38 M62TU Engine Workshop Manual 28
SECONDARY AIR INJECTION
Secondary air injections required to pre-heat the catalytic converters for OBD II compliance.
The system consists of the same components as previous systems with V8 specific BMW 735i 2001 E38 M62TU Engine Workshop Manual 28
SECONDARY AIR INJECTION
Secondary air injections required to pre-heat the catalytic converters for OBD II compliance.
The system consists of the same components as previous systems with V8 specific](/img/1/2821/w960_2821-27.png)
28
SECONDARY AIR INJECTION
Secondary air injections required to pre-heat the catalytic converters for OBD II compliance.
The system consists of the same components as previous systems with V8 specific loca-
tions.
The DME ME7.2 control unit controls the vacuum vent valve and the secondary air injec-
tion pump relay separately but simultaneously.
The secondary air pump operates at a start temperature of between 10°C and 40°C. It con-
tinues to operate for a max. of 2 minutes at idle speed.
ME 7.2 contributes an additional correction factor for secondary air “on” time with the addi-
tional input from the integral ambient barometric pressure sensor.
This sensor provides a base value to calculate the air mass being
injected into the exhaust system. This helps to “fine tune” the sec-
ondary air injection “on” time, optimizing the necessary air flow
into the exhaust system which reduces the time to catalytic con-
verter light-off.
VACUUM
VACUUM
VENT VALVENONPUMP/MOTOR
AIR PUMP SUPPLY HOSE
AIR DELIVERY TUBE WITH O RING
CONNECTIONS TO CYLINDER HEADS
VACUUM
CONTROL TO
NON RETURN
VA LV E