Withdrawal
Remove the outside air supply duct to the heater from the bulkhead.
Models 320i, 325i, 328i (Six-cylinder engine)
Use a narrow screwdriver to pry out the plugs -arrows- and remove the bolts underneath.
Unscrew the oil filler cap, remove the 2 upper plastic linings from the engine.
Loosen hose clamp -4- and disconnect fuel supply hose from distributor pipe.
Attention: The fuel system is under pressure. When disconnecting the hose, put a rag on and wipe off the escaping fuel. Flammable!
Loosen bolts -1- and disconnect connector block from injectors.
Unscrew securing bolts -arrows- for fuel rail. (In contrast to the image in the figure, the engine cover is removed).
Models 316i, 318i before August 1993
Remove the air hose from the throttle valve.
Loosen bolts -7- and nuts -8-.
Unscrew bolts -5- and -6-. Press intake air heater down. The heater is included in the engine cooling circuit. Leave the hoses connected. Pay attention to the position of the sealing ring for subsequent installation.
Pull out and fold down the top part of the intake manifold.
Remove the connector block from the injectors.
Remove bolts -9- from fuel rail.
Models 316i, 318i from September 1993, 318is/ti
Disconnect the air hose from the throttle valve fitting.
Disconnect the throttle cable.
Disconnect the vacuum hose from the brake booster.
Disconnect the 2 water hoses from the throttle body heater and plug the hoses with plugs, such as clean screws.
Disconnect the throttle switch connector -1- by pressing on the wire retainer.
Disconnect vacuum hoses -2-.
Remove 4 bolts -3- (Only 2 of them are visible in the picture) and carefully remove the throttle valve fitting.
Note: The throttle valve cannot be adjusted. In case of damage, such as from impacts, the throttle valve fitting must be replaced.
Unscrew front and rear manifold supports -4-.
Unscrew idle air control valve -5-.
Loosen the 3 bolts and remove the upper part of the manifold. Pay attention to the location of the centering sleeves -3- and -4- for subsequent installation.
Disconnect the connector block from the injectors and unscrew the bolts from the fuel distribution pipe (Drawing W 2246).
Six-cylinder engine: Detach vacuum hose -1- from fuel pressure regulator.
Disconnect the fuel hose -2- from the fuel distribution pipe, after releasing the clamp; use a rag to collect the leaking fuel.
Pull the fuel distribution pipe with the injectors out of the cylinder head. The nozzles are simply inserted and can be removed freely.
Pull retainers -4- out to the side and remove injectors.
Installation
Attention: When installing the injectors, do not damage the O-rings -1-. Replace defective rings, paying attention to the installation position of sealing ring -2-. Lubricate O-rings with Vaseline before installing with SAE90 Gearbox Lubricant.
Insert the injectors into the fuel distribution pipe and secure with clips.
Insert the injectors together with the fuel rail into the cylinder head. Lubricate O-rings with Vaseline before installing with SAE 90 Gearbox Lubricant.
Attach the fuel rail to the cylinder head with two bolts.
Connect fuel hoses.
Put the block with connectors on the injectors.
Models 320i, 325i, 328i
Fix the block with connectors with 2 bolts.
Install the engine cover.
Models 316i, 318i before August 1993, 318is/ti
Screw on the upper part of the intake manifold with new gaskets, making sure to install the centering sleeves. Tighten the screws evenly to 20 Nm.
Screw the manifold supports, as well as the idle air control valve, see the figure in the subsection "Withdrawal".
Screw on throttle valve connector with new gaskets -6- and -7-.
Connect 2 water hoses and secure the hoses with clamps. If coolant leaked out during removal, top up to normal level.
Connect 2 vacuum hoses to the throttle valve connector and a vacuum hose to the brake booster.
Connect the throttle potentiometer connector, it should click into place.
Connect the throttle cable.
Install air hose.
Start the engine and check the tightness of the intake tract, see section "Checking the idle speed / CO content".
Install the outside air duct on the bulkhead.
Checking the injectors
Remove nozzles. The injectors and fuel hoses remain on the fuel distribution pipe.
Put on the nozzle block with connectors.
Place the nozzles in an appropriate measuring vessel.
Have the assistant turn on the starter for a few seconds while comparing the injection jets of the individual injectors. The injection jet must be cone-shaped and have the same shape on all nozzles
Switch off the ignition.
Remove connector block from injectors.
Turn on the ignition for about 5 seconds without turning on the starter. After that, check the density: no more than one drop of fuel should come out of the nozzle within 1 minute.
Install injectors.
Power and resistance check
Check nutrition. To do this, remove the connector from the injector and connect a diode probe to the contacts of a suitable cable. Turn on the starter (assistant). The LED should light up.
If the LED does not light up, the cause of the defect may be a broken wire or a failure of the control unit.
Switch off the ignition.
Connect an ohmmeter to the contacts on the connector of each injector and measure the resistance. Setpoint see below.
Replace defective injectors.