Digifant, K-Jetronic, KE-Motronic (Mono-Jetronic see above)
The intake air heating is controlled by an air damper in the air filter box depending on the load and temperature. The air damper is controlled by a vacuum diaphragm mechanism by means of the vacuum generated in the intake manifold. The temperature regulator in the air filter box controls vacuum based on intake manifold temperature and vacuum. In the event of a violation of the intake air heating, the following claims to the operation of the engine may arise:
- Unsatisfactory idling of the engine during its warm-up;
- Faults in transients;
- Insufficient power, maximum speed is not reached;
- High fuel consumption.
Checking the air damper actuator
Check the strength of the fastening of the vacuum hoses from the membrane box (front right of the air filter housing) to temperature controller (top of the air filter housing) and from the temperature controller to the intake manifold.
Check the hoses for damage and porosity by bending them, replace the hoses if necessary.
Remove the upper part of the filter together with the filter element and check the position of the regulating flap in the lower part of the filter. The damper must close the warm air outlet -1-. Check the movability of the regulating damper, if necessary ensure its movability.
Disconnect the hose -3 - from the temperature regulator at the top of the air filter box and check the operation of the air damper by suction through the mouth. The damper should open and close audibly. If necessary, replace leaking vacuum membrane box.
Checking the temperature controller
Prerequisite for checking: the intake manifold must be in good condition, the engine must be tolerably hot to the touch. The maximum intake air temperature is +20°C.
Remove the upper part of the air filter together with the replaceable filter element, see below.
Connect both vacuum hoses to the temperature controller. The connecting union of the vacuum hose from the vacuum diaphragm mechanism may have the following identifying features: brown sticker next to the fitting: brass fitting at the temperature regulator: the fitting is slotted.
Start the engine and let it idle. The control valve should tighten within 20 seconds (cold air outlet -3- blocked, see figure 24-233).
If the intake air temperature is between +20°C and +30°C, the air damper must be located between both connections -1- and -3-. At an intake air temperature of more than +30°C, the air damper must completely close the intake air pipe.
If not, clean the 2 openings of the temperature controller on the inside of the intake air duct or replace the temperature controller accordingly.
Install air filter, see below.
Visitor comments