Hey all, I have spent a few days now googling and reading various texts around the internet. I have transplanted a PD100 ATD in to my 1989 3 Door MK2 Golf I have chosen to remain with the Factory Dash and Clocks (CE1) and So Far everything has been great, the car drives great, and goes very very well. Wanting to add a further dimension to the driving experience I opted to get Launch Control enabled on the Factory ECU, HOWEVER... This function only works correctly when the ECU Sees the Road Speed as most of you will already know. I have been trying to get the VSS output from the MK2 GTI Cluster to send Speed information back to the ECU Testing Several spare MK2 Clusters they all seem to put out 5Volts down the White/Yellow Wire and the Voltage seems to pulse when I spin the Speedo Drive (assuming this means it is working) I have even Jerry Rigged the original MK4 Gearbox Speed Sensor and tried to input that in to the ECU also with no result? (the output signal from this was very different to the MK2 Cluster's) Connecting it all up in the Manner that is suggested in RubJonnys MK2/MK4 Bible the ECU doesnt appear to see any Speed. After looking thru the Current Flow Diagram in the Factory MK4 with the ATD engine the G22 Sensor connects to the Circuit in the Following Manner G22 Output (pin2) -> Input on the Cluster for RPM T32/28 (Blue connector on the Instrument Cluster) Apparently the Speed Signal that is sent to the ECU originates from a Different Pin on the Instrument Cluster T32/3 -> Feeds the ECU Speed Thru T121/20 Keeping in Mind I do not have the MK4 Clocks in this Car..... Do the Clocks further convert the Signal before passing them back to the ECU? Also does any one know if the MK4 ECU Required a 5V or a 12V Pulse for the VSS Input? Am I missing something completely obvious. Otherwise I shall Concede Defeat for now and just keep driving as is
The MK2 clock signal is compatible with the MK4 ECU, I'm currently using it to drive my MK4 climatronic and central locking module install and it registers the speed just fine in the measuring blocks/secret menu so this is a bit of an odd one! can you try a different ecu perhaps? also check the t121/20 wire make sure it isnt shorting out anywhere and has continuity from the clocks to the ecu pin
Hi Rubjonny thanks for the reply. I thought this was the case also but its proving to be a pain in the ass. That said I even purchased a Speedpuls 4p vss sender from Fastforward.ca to retrofit in to the cluster. I havent attempted that yet as I was dubious about sending a 12v Signal in to the ECU I will double check the continuity again. I am adamant It was there. In my particular instance the wire colours do not even closely resemble the diagram but match the pin outs. BLUE/PURPLE Unfortunately no other ECUs available at present PD TDIs are rare enough as it is in NZ. Will double check and revert later.
maybe check the speed sensor output setting in the mfa secret menu, see if it registers correctly when driven/speedo spun: http://www.clubgti.com/showthread.php?219196
Ironically I never installed the MFA stalks on the column just left the cluster in clock mode as default. I will plug them in and test that out today also.
SOLVED: After checking continuity the first time and subsequently crimping on the quick release connector so i could connect the two looms semi permanently the wire broke further up the loom while pulling on it. I should have checked the continuty again as i just had.... Silly me thanks for your help rubjonny.
