The second common source of radio interference is the ignition system. In this case, connect a 1.0 uF capacitor between "earth" and terminal "SW" or "+" ignition coils (see b/fig. 10.11). This will remove "ticking" sound from speakers.
Another source of noise is spark plugs. The Peugeot 305 uses special ignition wires with built-in radio interference suppression, but if these are replaced with regular ones, problems may begin.
To suppress radio interference from candles, you can install special resistive caps on them (see b/fig. 10.12), the resistance of which is from 10,000 to 15,000 ohms. If, due to lack of space, it is not possible to install resistive caps, linear radio interference suppressors can be used (see b/fig. 10.12) (if the noise is not too strong, it is enough to install one suppressor on the wire between the coil and the distributor. If this does not help, suppressors must be installed on all ignition wires).
Check the grounding of the radio and antenna. If possible, achieve the minimum length of the power cable of the radio.
If all common sources of radio interference have been checked and "rendered harmless", and the noise does not disappear, all electric motors, light interrupters and appliances should be checked. The solution to the problem in this case is shown in B / fig. 10.13 (not very strong interference from the electric motor) and 10.14 (interference from working devices). Interference from the light interrupter is generally not suppressed. Recently, when a radio receiver was factory installed, in addition to a fuse, a choke was installed on its supply line, which also helps to suppress radio interference. If you do not have such a throttle, install it as shown in B / fig. 10.15.
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In the case of a transistor radio, it is enough to set the choke to 2 A. If you have an electric clock in your car, interference from them is removed using a 0.5 microfarad capacitor, installed as shown in B / fig. 10.13 for the electric motor.
If, after all the measures taken, the interference does not disappear, check if they are passing through the wires. You can try to replace the usual supply wire with a shielded one.
In the worst cases, check if interference is caused by pickup from ~ metal parts of the car rubbing against each other (with poorly tightened fasteners). Interference of this kind is removed by shunting "noisy" connections with a wide earthing bar with a braid. The most likely sources of interference may be attachment points:
- A. muffler
- b. exhaust pipes (at the point of contact with the cylinder block)
- V. air cleaner
- d. front and rear bumpers
- d. steering column
- e. bonnet and trunk lids (their castles)
Interference of this kind is most noticeable (1) at idle (2) under engine load.
A pulsating grinding noise when driving can be caused by a buildup of static electricity on the wheels or tires. In order to remove them, you need "squirt" in each tire a special antistatic powder.
Interference in the form of a piercing howl that changes its tone as the car moves and comes and goes can be caused by the antenna (especially telescopic). In order to remove them, it is enough to install a small rubber ball on the end of the antenna. If noise occurs during braking, it is caused by the buildup of static electricity in the brakes (especially noticeable in hot dry weather). Such interference can only be removed by installing a special, very expensive brake kit.
Car radios are less susceptible to interference, but if the latter do occur, you should remove the interference from the generator and the ignition system and install a 3-5 A choke on the supply wire. In the most severe cases, you can shield the supply wire and wires going to the speakers.
Note: in the case of an electronic ignition system, it is not recommended to put resistive caps on candles or a capacitor on the ignition coil. because this may damage the system. Most electronic ignition systems have built-in radio interference suppressors.