[hiawata]

This is all that you need to do to use your original mk2 fuelsender to work with mk4 instruments:

Just solder the blue wire on the opposite side of its original place:

I have done it on my mk2 with A3 dash and instruments, more info in my project thread:
http://forums.vwvortex.com/showthread.php?4059536-My-turboed-Mk2-syncro&p=65686718&viewfull=1#post65686718

[hiawata]

Here is a couple of pictures from inside the Haldex.

[hiawata]

I am doing some similar work as Audi Doody for my own build.
I am using picaxe microcontroller to controll the stepper in the Haldex unit.
Here is some of the work I have done so far:
Electronic diagram:

Program so far:

symbol adc_value = b1
symbol desiredposition = b4 ;
symbol oldposition = b5 ;
symbol numberofsteps = w3 ;
symbol numberofmoves = b8 ;
symbol direction = b11
symbol ant_step = w6
b9 = 4 ;

main:
pause 2
readadc 1, b1 ;

if b1 < 42 then
desiredposition = 0 ‘1st segment
elseif b1 < 85 then
desiredposition = 1 ‘2nd segment
elseif b1 < 128 then
desiredposition = 2 ‘3rd segment
elseif b1 < 170 then
desiredposition = 3 ‘4th segment
elseif b1 < 213 then
desiredposition = 4 ‘5th segment
else
desiredposition = 5 ‘6th segment
end if

if oldposition = desiredposition then
‘No need to move so check again
goto main

elseif oldposition > desiredposition then
‘If needed to move then work out how far
numberofmoves = oldposition – desiredposition
numberofsteps = numberofmoves * 500
direction = 0

else
‘If needed to move then work out how far
numberofmoves = desiredposition – oldposition
numberofsteps = numberofmoves * 500
direction = 1
end if

if direction = 1 then
gosub movestepper
else
gosub movestepperback
endif
oldposition = desiredposition ;
goto main ;

MOVE:

movestepper:
for ant_step = 1 to numberofsteps
b2 = b2 + 1
b2 = b2 & %00000011
LOOKUP b2, (%1001, %0101, %0110, %1010), b3
pins = b3
pause b9 ;
next ant_step
return

movestepperback:
for ant_step = 1 to numberofsteps
b2 = b2 – 1
b2 = b2 & %00000011
LOOKUP b2, (%1001, %0101, %0110, %1010), b3
pins = b3
pause b9 ;
next ant_step
return

I will not promise any timeline when this will be finished or if I`ll post more of the code when I am getting closer to my goal.

Want to see my projectcar, G2 1.8T syncro (to be Haldex):
http://forums.vwvortex.com/showthread.php?4059536-My-turboed-Mk2-syncro

[hiawata]

The Motronic ECM provides the following
signals to the Haldex control module along
the CAN bus:
• Engine speed signal
• Accelerator pedal position
• Engine torque
Effects of signal failure:
• The Haldex unit will not operate

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