Engine idle adjustment. Before adjusting the engine idle, perform the following operations:
- make sure that the air damper is fully open;
- check the cleanliness of the air filter element and replace it with a new one if necessary (do not remove the air filter when adjusting the engine idle);
- warm up the engine. To do this, let the engine run at a crankshaft speed of about 2000 rpm. until the thermostat opens. In no case should you warm up the engine at idle, because if the engine runs for several minutes at idle, then the measurements of the carbon monoxide content in the exhaust gases will be distorted;
- check the operability of the ignition system and the setting of the ignition timing;
- check that there is no air leakage, paying particular attention to the connection of the vacuum hoses and the condition of the throttle body gasket;
- make sure that there are no significant exhaust gas leaks in the exhaust tract;
- make sure that powerful current consumers (engine cooling fan, headlights, rear window heating element, etc.) off. The idle speed of the engine is adjusted using the adjusting screws (pic. 2-40).
Set the engine crankshaft speed within 750-850 rpm with the adjusting screw for the amount of the mixture.
Connect the gas analyzer according to the instructions. Remove the plug of the quality adjusting screw (composition) mixture and turning it. to achieve the content of CO in the exhaust gases in the range of 0.5-1.5%.
If necessary, restore the specified idle speed of the engine crankshaft with the mixture amount adjusting screw. Repeat these operations until the specified values of the crankshaft speed and CO content are obtained. After adjustment, put in place a new plug of the quality adjustment screw (composition) mixtures.
Adjustment of the accelerated idling of the engine. Fast idle adjustment is performed on a warm engine (oil temperature not less than 60°С), with correctly set ignition timing and adjusted idling.
Install adjusting screw 1 (fig 2-41) fast idle on the second, upper profile 2 throttle control cam.
Start the engine without depressing the accelerator pedal.
Check the engine speed at fast idle, which should be within 1650-1750 rpm. If necessary, set the required mode of accelerated idling of the engine with the adjusting screw 1.
Checking and adjusting the starting clearance of the air damper. Disconnect the vacuum hoses from the air damper actuator. Close the choke and install the fast idle adjusting screw on the top profile of the throttle control cam.
Attach a vacuum pump hose to the lower fitting of the pneumatic actuator and create such a vacuum using the pump. at which the air damper stops moving.
Do not change the vacuum, use a rod or drill to measure the starting clearance of the 1st stage of the air damper, which should be in the range of 1.5-1.9 mm. If necessary, adjusting screw 1 (pic. 2-42) set the required clearance. After the adjustment, connect the hose to the upper branch pipe of the pneumatic actuator.
Create a vacuum of 0.5 kgf/cm using a vacuum pump2, then check the starting clearance of the second stage of the air damper, which should be within 2.8-3.2 mm. If necessary, achieve the desired clearance with the adjusting screw 1.
After adjustment, remove the pressure gauge and connect a hose to the lower branch pipe of the pneumatic actuator.
Throttle opening adjustment of the 2nd chamber. The 2nd chamber throttle position is set at the factory. but in the event of a violation of the adjustment, it can be restored on a previously removed carburetor as follows:
- fully open the throttle valve of the 1st chamber and fix it in this position by inserting a drill between the edge of the valve and the carburetor body;
- tighten the throttle lock lever of the 2nd chamber with an elastic band;
- unscrew the restrictive screw of the throttle valve of the 2nd chamber so. to get him off the hook. Then screw in the limit screw so that it barely touches the stop;
- turn the stop screw another ¼ turn and lock it in this position:
- return the throttle valve of the 1st chamber to the closed position;
- install the carburetor.
Checking the tightness of the air damper actuator. Remove the air filter and disconnect the vacuum hoses from the air damper actuator.
Plug the lower outlet pipe of the pneumatic actuator.
Connect the hose of the manual vacuum pump to the upper outlet pipe of the pneumatic actuator and create a vacuum of 0.3 kgf / cm 3 in the pneumatic actuator with a pump2. If the vacuum does not remain unchanged, the pneumatic actuator must be replaced. Checking and adjusting the performance of the accelerator pump. Remove carburetor. Rotate profiled cam 1 (pic. 2-43) throttle control so that the fast idle adjusting screw 2 moves away from it. Place a graduated vessel with a funnel under the carburetor.
Slowly fully open and close the throttle valve of the 1st chamber ten times. thus activating the accelerator pump (in this case, the fuel must exit the pump nozzle every time for at least 3 s). Determine the amount of fuel leaked into the vessel: it should be within 7-10 cm3. If the performance of the pump does not correspond to this, loosen the locking screw 3 and turn the pump drive cam to set the required performance. Turning the cam to the left increases the pump output and vice versa. After adjustment, tighten the locking screw 3 and lock it with a special pack.
Pic. 2-44. Elements of the air path:
I - carburetor engine power system «EZ»
II - fuel injection systems «Mono-Jetronic» engine «PR» without classical neutralizer
1 - air intake pipe
2 - air filter housing
3 - air filter element
4 - warm air supply hose
5, 6 - casing
7 - central injection unit
8 - base of the carburetor body
9 - the base of the central injection unit
10 - inlet pipeline
11 - gasket
12 - intake manifold heater
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