Problems with A6 2.5 TDi conversion

[HarlequinSyncro]

Hi,
I've installed an Audi A6 2.5 TDi 5 Cyl (AAT code) into my Vanagon Syncro but have a little glitch with the throttle.

On very light throttle, the engine backs itself off back to tickover and once there I can very slowly fully depress the throttle to the floor and it makes no difference to the engine rpms.
However, if I back off the throttle manually and depress it again slightly quicker then its not a problem.

Also, I have the 2 plugs for the brake and clutch pedal switches currently setup so that the clutch (light brown plug) is looped and the brake (black plug) is open. Is this right?

Thanks in advance.

MG

 

[HarlequinSyncro]

Just to clarify the wiring. The 2 plugs are as follows:

Black plug with 2 wires, Red with Grey trace and Black with Green trace (I have this as the brake pedal switch for the ECU)... Currently not connected up or looped.

Beige plug with 2 wires, White with Red trace and Black with Green trace. Currently looped on itself. I have this as the clutch pedal switch.

I don't yet have a vehicle speed sensor for the ECU which I guess won't be helping but I can't imagine it would cause the throttle to be like this at rest as well as on the move?

MG

 

[DPM]

At a guess, if you don't have a VSS connected the throttle response will be limited- the ECU does fancy stuff dependant on inputs from VSS and clutch switch to determine how much max. power the motor can put out, IIRC.

 

[HarlequinSyncro]

Do you think I should fit and connect up the clutch and brake switches then?
I am about to order a VSS from FastForward in U.S. which should keep the ECU slightly happier.
Thanks
MG

Oh.. I forgot, the engine is from a 1996 car so early TDi.

 

[HarlequinSyncro]

Throttle problem sorted. Thanks to David at Fast Forward for some in depth advice regarding brake light switches and clutch switches...and the VSS.

 

[ninedee_golf_tdi]

So what did you learn ?