SYNCRO.CA
1989 TriStar Syncro Project

PART TWO - ENGINE UPGRADE

Section IV: PREPARING THE VEHICLE FOR THE TDI ENGINE

Lots of stuff has to be done for the vehicle to prepare it for the TDI motor! 

Preparing the fuel system:

Step 1 0h15m
  • Drain the fuel tank of all gasoline.

    This can be done by supplying the gasoline fuel pump 12V until the tank runs dry.  The fuel pump can remove more fuel than just draining the tank.
Step 2 1h00m
  • Remove filler neck restrictor.

    This is done by removing the filler tube between the tank and the filler cap.  The 'neck' of the filler tube is crimped on to the plastic filler tube.  Use a hand held grinder to cut the crimp.  Once the tube is pulled out of the neck, the restrictor can be removed.  Install the neck again and use a hose clamp to secure it in place.  Reinstall the fuller tube.
Step 3 0h15m
  • Rinse the fuel tank.

    This is done by putting about 5L of Diesel fuel into the tank.  Use the gasoline pump to remove all the Diesel from the tank.
Step 4 1h00m
  • Remove fuel pump and fuel pump wiring.

    Replace the smaller fuel line between the pump and the original motor and the return line as over time they get brittle and can leak.  Make sure there is enough hose in the engine compartment to easily reach the front right corner where you will locate the Diesel fuel filter / water separator.  A common brass 1/8" to 1/4" barbed fitting can bridge the new hose that is installed and the original hose that came from the tank.  Make sure you cover the ends of the hoses so that they do not get contaminated with dirt.

    Suggestion: Now is a good time to put about 10L of Diesel fuel in the tank.  
2h30m


Total time for preparing the fuel system.

Preparing the electrical system:

Step 1 0h15m
  • Remove the unnecessary wires from the engine compartment.
  • Remove the fuel pump / ECU relay box

    There should be only a hand full of wire left in the engine compartment.  The BK and GN wires that went to the coil.  The Y/R wire that went to the coolant temperature sensor. The  BL/BK and Y wires to the oil pressure switches.  The R and R/BK wires that went to the relay box.  The BK and BR wires that went to the original wasserboxer crank case vent heater.  
Step 2 1h00m
  • Install a pin switch on the brake pedal and the clutch pedal

    These switches should 'on' when the pedals are at rest and 'off' as soon as you begin to press the pedal.  These switches are used for the cruise control and by the ECU.  

    Caution: The AHU and ALH engines use different types of signal logic for the pedals!  Please follow the instructions with your wire harness as to if you are to connect 12V or ground to one side of the switch.
Step 3 0h45m
  • Run a 10 conductor, shielded cable from the engine compartment the instrument cluster.  Printer cable or CAT5 works well.
  1. Malfunction Indicator Light - Red LED to be installed in instrument cluster.
  2. Glow Plug Light - Yellow LED to be installed in instrument cluster.
  3. Brake Pedal Switch - connect to switch installed in step 2
  4. Clutch Pedal Switch - connect to switch installed in step 2
  5. K [OBD line] - have it so that it reaches under the ash tray where the OBD connector will be installed.
  6. CAN Bus - High [OBD line - ALH only] - have it so that it reaches under the ash tray where the OBD connector will be installed.
  7. CAN Bus - Low [OBD line - ALH only] - have it so that it reaches under the ash tray where the OBD connector will be installed.
  8. Spare - gotta have a spare wire right!? - Can be used for cruise control too!
  9. Spare - gotta have a spare wire right!? - Can be used for cruise control too!
  10. Spare - gotta have a spare wire right!? - Can be used for cruise control too!
  • Run a 2rd CAT5 cable from he engine compartment to the instrument cluster if you are using the ALH style throttle pedal. Can be used for cruise control too!

    Suggestion:  If you are going to install an oil pressure gauge, EGT gauge or other accessories that require cockpit monitoring there will be enough spare wires in the CAT5 cables to accommodate this.  Remember to use cable like this only for signals and not for anything that requires any current.
Step 4 1h00m
  • Install a VDO tachometer from a 1985 to 1992 Diesel Jetta or Golf in place of your gasoline tachometer.

    Four out of five Vanagon tachometers are not sensitive enough to use the tachometer signal from the TDI ECU.  We recommend installing the above tachometer and using the signal from the W terminal to drive it.  More than likely it will need some adjusting, there is a small adjusting potentiometer at the rear of the tachometer.  The Vanagon fuel gauges and coolant temperature gauges will transfer directly over to the new tachometer.
Step 5 1h00m
  • Install high torque starter
  • Reroute wiring for new connection positions
4h00m

Total time for preparing the electrical system.

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2004 David Marshall