If there are no instruments, at least a speed sensor is required, connected in accordance with the operating manual. If you follow the recommendations, adjusting the idle speed should not cause any difficulties. On an engine with electronic idle speed control, there is no need for adjustment. The system is installed on cars with automatic transmission and air conditioning. There are some differences between pneumatic and electronic idle speed control systems. When adjusting the idle speed, you must proceed as follows:
- make sure that the fuel pedal control rod moves freely and does not stick. The latter is often the cause of increased idle speed;
- start the engine and bring it to operating temperature;
- check the idle speed. For an engine with a pneumatic rev-up system, this value should be (750±50) min⁻¹, with an electronic one — (720±10) min⁻¹. Otherwise, adjustment is required;
Figure 172. Disconnecting the accelerator rod (1) from the lever (2)
- according to the drawing 172 disconnect rod 1 from throttle lever 2.
Figure 173. Location of the fuel pressure regulator: 1 — lock nut; 2 — regulator; 3 - vacuum hose
Figure 174. Idle speed adjustment
Idle speed is set on the fuel pressure regulator, the location of which is shown in the figure 173. To adjust, loosen lock nut 1 and turn regulator 2. First, disconnect vacuum hose 3 from it. The adjustment operation is shown in the figure 174, which shows that the lock nut fastening needs to be loosened with an open-end wrench. After adjustment, insert the hose back.