Nozzle elements
1 - nozzle; 2 - plugs on the free fuel outlet pipe of the injector of the 4th cylinder; 3 - injection high pressure pipeline; 4 - connecting hose between two nozzles.
Roto High Pressure Fuel Pump Elements
1 - idle adjustment washer; 2 - throttle lever; 3 - exhaust gas microswitch; 4 - full load microswitch; 5 - solenoid control shutdown device; 6 - throttle control cable; 7 - device for moving the membrane «fast» idle move; 8 - boost pressure regulator; 9 - electromagnetic clutch advancing fuel supply; 10 - idle stabilization limiter; 11 - lever «quick» idle move.
4 tension bolts are responsible for controlling the speed of the Bosch high pressure fuel pump.
1 - full load limiter; this limit screw is factory sealed (adjustment of this bolt is carried out only on a special test bench);
2 - persistent (restrictive) idling stabilization screw;
3 - restrictive screw for adjusting normal idle;
4 - limit screw for adjustment «fast» idle move.
Since the thermal switch (1) Since the cold start accelerator acts on the fuel injection advance clutch, its failure creates difficulties not only during engine start, but also during the warm-up period. Numeric «2» an electrical connector is indicated, which must be disconnected when checking the switch.
Below are some of the work that makes sense to do it yourself. For example, sealing a leaking high pressure fuel pump. This defect often manifests itself in the position change lever (lever arm «combustible mixture»). To eliminate such a malfunction, it is still better to contact a car repair shop.
1. Purchase a new heat shield for each nozzle.
2. Disconnect the battery terminals and cover the generator with a rubber mat to protect it from diesel fuel.
3. Remove the injection lines and apply adhesive tape to keep dirt out.
4. Remove the outlet pipes and stick an adhesive tape to protect against dirt from entering the holes of the fuel pump and injectors. Wipe off any remaining diesel fuel with a clean cloth.
5. Unscrew the nozzles with a wrench SW 27; be careful not to drop the nozzles.
6. If the heat shield is in the nozzle opening, use a plastic ballpoint pen or a wire hook to remove it.
7. Use only a new heat shield for installation.
8. Tighten the injectors to a torque of 70-80 Nm and the union nuts of the high-pressure fuel lines to a torque of 15-25 Nm.
Note. Recommendation: Depending on the type of high pressure fuel pump (especially export cars!) and because of this different fuel pressure, each pump is equipped with nozzles specially tuned for it. Therefore, when purchasing spare parts, you should always purchase only suitable parts.
Nozzle disassembly
If contaminated, the nozzle must be disassembled. It is better to completely replace the faulty injectors with new ones. When disassembling, it is important to remember: the nozzle must not be left open, it must be installed immediately and then let the engine run. Otherwise, the nozzle parts can quickly rust to each other. Tightening torque for the lower and upper parts of the injector: 70 Nm.
Note. Recommendation: when you check the serviceability of the nozzle, always make sure that the jet from the nozzle is directed away from you. The injection pressure is so strong that it can cause damage if it comes into contact with the skin.
Malfunctions of the shutdown device of the solenoid control
1. The solenoid control shut-off device to stop the engine shuts off the fuel supply to the injectors. The solenoid control shut-off device is suspect if the engine does not start despite the preheat device working and the tank full. Solenoid control shutdown device test sequence:
2. While the assistant turns the ignition key, you listen to see if the solenoid control shut-off device makes a click. If no click is heard, there is no power or the solenoid control shutdown device itself is defective.
3. Power test: turn on the ignition and connect a test lamp to the terminals of the solenoid control shut-off device.
4. If it is lit, the solenoid control shutdown device is faulty.
5. If it does not light up, then the wire coming from the ignition switch is faulty. There is no fuse in the connection.
Note. Recommendation: With the ignition on, the solenoid control cut-off device should become hot after a while.
Driving with a faulty solenoid control shut-off device
If the solenoid control cut-off device is defective or not receiving power, you can still drive on. For this:
1. Clean the work surfaces around the solenoid control shut-off device.
2. Disconnect the wire from the solenoid control disconnect device.
3. Unscrew the solenoid control shut-off device from the high pressure fuel pump.
4. Remove the valve piston and spring from the solenoid control disconnect device.
5. Screw the housing back into place as a seal.
6. In this case, the engine will start as usual, only to stop the engine it will be necessary to turn off the engine by shifting the gear.
Note. leak in throttle lever connection (throttle lever) high pressure fuel pump can be fixed by replacing the throttle lever shaft O-ring. This work is done in a Renault or Bosch workshop.
Faults: Cold start accelerator thermal switch
Thermal switch fault can only be set at low temperature. To do this, with the engine cold, with the thermal switch wire removed, start the engine and then connect the wire to the thermal switch. If the speed changes noticeably, then the thermal switch is OK. Power supply health check:
1. Check if there is electricity. To do this, connect a test lamp to the contacts of the thermal switch and turn on «ignition».
2. If the control lamp does not burn, then the wire from the ignition switch is faulty; however, this means that the solenoid control shutdown device is not working either.
Faulty cold start accelerator
A cold start accelerator malfunction can only be accurately determined on a cold engine (coolant temperature below 15°C).
1. Start the engine and observe the movement of the lever «fast» idling in the high pressure fuel pump, whether it moves slowly to another limiter.
2. Turn off the ignition - the thermal switch should re-tighten the cold start accelerator lever after a while.
3. Checking with a cold engine running: the speed should noticeably decrease after 1/2-3 minutes.
Removing the cold start accelerator actuator
1. Remove the connecting rod from the idle lever. To do this, unscrew the screw nipple and remove from the rod.
2. Unscrew the Bowden cable thermal switch from the cylinder head.
3. After installing the thermal switch on a cold engine, press the idle speed lever to the limiter to «fast» idle, insert the screw nipple and tighten so that the lever «fast» idle was in position «fast» idle move. Check RPM (1110-1200 rpm).
4. When reaching operating temperature (once the fan turns on) the gap on the tensioned cable from the screw nipple to the idle lever should be 2-3 mm.