Auxiliary Engine Coolant Heater, Fuel Supply
Auxiliary Engine Coolant Heater, Fuel Supply
Cleanliness Rules
When working on the fuel supply/injection system, pay careful attention to the following "5 rules":
- Thoroughly clean all unions and adjacent areas before disconnecting.
- Place parts that have been removed on a clean surface and cover. Only use lint-free shop rags.
- Carefully cover opened components or seal, if the repair cannot be carried out immediately.
- Only install clean components: Only unpack replacement parts immediately prior to installation. Do not use parts that have been stored loose (e.g. in tool boxes etc.).
- Fuel hoses and pipes may only be shortened using a clean sharp knife. Cutting points must not be soiled or deformed. Cutting points and surfaces must be free of burrs.
Auxiliary engine coolant heater, fuel line routing
NOTE:
- Fuel lines are secured with clamp type clips. These clamp type clips must always be replaced with screw type clips.
- Start vehicle engine if fuel tank was empty. Then start auxiliary engine coolant heater several times until the heater does not switch off by itself.
- Observe cleanliness rules when working on fuel supply system
- The metering pumps for auxiliary coolant heaters Z/CB (gasoline) and Z/CD (diesel) have different flow rates; observe part numbers. Note replacement part numbers.
1 - Metering Pump V54
- Fuel delivery, checking
2 - Fuel Level Sensor
- Location: on right under rear seat
3 - Fuel line
4 - Auxiliary engine coolant heater
Auxiliary engine coolant heater fuel supply line, location
- Lift right rear seat cushion.
- Remove screws (20 Nm) - arrows - and retainer.
- Cut through carpet (along the position as marked) with a knife and fold carpet back.
- Remove nuts - arrows - and cover plate.
- Auxiliary engine coolant heater fuel supply connection on fuel gauge sender - arrow.
Metering Pump V54, removing and installing
Removing
Special tools, testers and auxiliary items required
- Hex Ball Socket SW 5 VAS 3249 (or equivalent)
- Disconnect electrical connection - 5 -.
- Loosen clamp - 2 -.
CAUTION:
- There is a danger of leaking fuel.
- Fuel system is under pressure.
- Before opening the system place a cloth around the connection. Then release pressure by carefully loosening the connection.
- Pull fuel hose - 3 - off metering pump and seal.
- Remove screw - 4 - with Hex Ball Socket SW 5 VAS 3249 and remove Metering Pump 1 - with bracket.
Installing
Install in reverse order of removal.
- Observe installation position of metering pump.
NOTE:
- Fuel lines are secured with clamp type clips. These clamp type clips must always be replaced with screw type clips.
- Observe cleanliness rules when working on fuel supply system
- The metering pumps for auxiliary coolant heaters Z/CB (gasoline) and Z/CD (diesel) have different flow rates; observe part numbers. Note replacement part numbers.
Fuel delivery, checking
Special tools, testers and auxiliary items required
- Vehicle Diagnostic, Testing and Information System VAS 5051
- Multimeter V.A.G 1526/A, Fluke 83 (or equivalent)
- Connector test set V.A.G 1594/C
- Wiring diagram
- Commercially available measuring glass (0 ml to 25 ml)
- Fuel hose, length approx. 300 mm
Test prerequisites:
- Metering pump resistance 5.4 ohms
- Voltage at metering pump, 11 to 13 Volt.
- No Diagnostic Trouble Code (DTC) stored in memory
- Fuel lines are not damaged or leaking.
- Ambient temperature approx. 20 degrees C
- Fuel tank is filled sufficiently (fuel gauge on dash panel is not in red area).
CAUTION:
- There is a danger of leaking fuel.
- Fuel system is under pressure.
- Before opening the system place a cloth around the connection. Then release pressure by carefully loosening the connection.
Checking:
- Remove fuel line from pressure connection of Metering Pump V54 and fit new fuel hose (length approx. 300 mm) from pressure connection to measuring glass (capacity approx. 25 ml).
- Hold measuring glass at same height as auxiliary engine coolant heater.
- Use Vehicle Diagnostic, Testing and Information System VAS 5051 and select vehicle system "18" "auxiliary heating". Select function ""10"" Adaptation, and channel number 1. Enter value 29 and finally confirm with Q key.
- After approx. 60 seconds the fuel line is filled and bled.
- Empty measurement container.
- Hold measuring glass at same height as auxiliary engine coolant heater.
- Use Vehicle Diagnostic, Testing and Information System VAS 5051 and select vehicle system "18" "auxiliary heating". Select function ""10"" Adaptation, and channel number 1. Enter value 29 and finally confirm with Q key.
- Read measuring glass. Quantity delivered: Diesel: 16.2 ml to 17.8 ml
- If the quantity delivered is not within specifications, replace Metering Pump V54.
NOTE:
- If ambient temperature is above 20 degrees C then fuel vaporization may lead to incorrect measurements being achieved.
- No bubbles are to be delivered.