Checking the injectors
Switch off the ignition as described in the relevant section.
To check if fuel is getting to the injector, loosen the fuel line bolt on the cold start valve.
Prepare a rag and ask an assistant to crank the starter.
If fuel comes out, check the injector itself.
Remove injector (see later in this section).
To do this, on some five-cylinder engines, it is necessary to remove the upper part of the intake manifold.
Keep a container or rag ready to collect escaping fuel.
Remove the large air hose between the mixture adjuster and the throttle valve to access the flow meter gauge plate.
In the central switchgear, disconnect the fuel pump relay and bridge the contacts on the block with a piece of wire. The fuel pump must be running.
The measuring plate in the dispenser should be lifted slightly by hand. In this case, the injector must create a conical jet. If this is not the case: Raise the measuring plate as far as it will go. Repeat check.
In this way, the difference in the amount of injected fuel between the individual cylinders can be checked.
Each injector should be lowered into its own measuring cup (there should be four or five), without bending the high pressure fuel lines.
Raise the measuring plate by approx. 2 cm.
The aforementioned wire jumper must be kept inserted by an assistant until 2 cm3 of fuel is poured into the first cup.
Compare the amount of fuel in different cups. The difference should not exceed 3 cm3.
If the deviation is greater, the injectors with the minimum and maximum amount of injected fuel should be swapped. Repeat measurement.
If with the change of injectors the deviations in the amount of fuel also reversed, then the injector with excessive deviation must be replaced.
If you received the same results during the re-check, then the fuel line leading to the injector may be narrowed or the fuel dispenser is faulty.
Checking the tightness of the injectors: if you turn off the fuel pump after two minutes of operation (pull out the jumper), from the injectors should not drip.
The injector installation procedure is described below.
Injector (1) removed with o-rings (3) and connected high pressure fuel line (2). Shown here is an injector with two O-rings. The figure on the right shows the principle of operation of an air-blown injector. By supplying additional air (highlighted in lighter color) better fuel atomization is achieved (darker color) in idle mode.
Checking the cold start relief valve
Check is made at the cooled-down engine.
Switch off ignition.
Unscrew the cold start valve, leaving the plug and fuel line connected.
Lower the valve into the vessel, ask the assistant to turn the engine.
The valve must produce a conical fuel jet.
The duration of injection depends on the temperature of the engine. At a temperature of 0°C, the duration of the injection ranges from 3 to 7 ½ seconds, at 10°C - from 2 to 6 seconds, at 20°C - from 1 to 4 seconds. Switch off ignition after injection.
Dry the valve by blotting it. No fuel should come out for one minute.
Checking the fuel dispenser
Let the engine run for approximately one minute.
Remove the air filter cover and filter element
From below, press the setting lever all the way up through the inlet shaft of the measuring plate. The same resistance should be felt throughout the entire stroke.
No resistance should be felt when the measuring plate is quickly pulled back. If it is, the air mass meter needs to be replaced.
If the measuring plate moves up with difficulty, but moves down easily, then "sticky" distribution piston in the dispenser. Replace fuel dispenser.
Checking the air mass meter
Warm up the engine, or run the warm engine for approximately 1 minute before testing.
Remove the intake air hose between the mixture adjuster and the intake manifold by loosening the tie-down bands.
Check the measuring plate: the measuring plate must be 1.9 mm below the top edge, at least 3 mm below.
If the meter plate is not positioned correctly, it must be lifted by bending the retaining wire clip at the bottom of the air mass meter shaft to correct its position. Under no circumstances should the flat spring be bent.
Check if the measuring plate is touching the wall.
If so, loosen the central fixing bolt and re-center the plate.
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