Throttle Position Sensor or Vac advance

[1985VK]

Just curious about the TPS Throttle Position Sensor/Switch on the carby of the VK. It has two wires to the microswitch. How does it work? How it does it tell where the throttle is at?

 

[1985VK]

I just found out how it works. It goes on a VK EST carby instead of a non EST carby. The mechanic swapped out the EST carb for a non EST carb and put the microswitch on it anyway. It does not work as it should and is only attached to the bracket by one bolt because the front of a VH carby is wider. The bracket doesn't fit properly ... and he didn't bother to tell anyone ...

So there is no lever to act on the microswitch. When the plunger is pressed down there is no lever to do anything ... the microswitch just sits there ... this bloody carb has been like that for yonks ... it seems like an on or off kind of thing ... very basic ...

So this EST engine has a non EST varajet on it ... no wonder it pings at operating temp under load ...

 

[whats up]

 

[1985VK]

Yes it has been pinging since the change. It is good when cold under load but when its warmed up it starts to ping. I don't know why they call it pinging, it sounds more like shaking a baby rattle to me. The head is factory standard. The computer is still hooked up.

I was looking over the engine and noticed the microswitch on the carby looked a bit strange. It just had the 2 wires to it and the lever was missing that worked off the plunger. It has power to it but nothing can press against the switch. I presume it thinks it is always under load?

 

[whats up]

 

[1985VK]

Yep got the electric choke. No smoke on start up. The engine runs well otherwise, just rattles a bit here and there when it gets warm and under load at operating temperature. The rattle is faint but i can hear it. I thought it was because the timing is out. If i give it more juice the rattle goes away but i'm being heavy on fuel to get away from the rattling.

It has a non EST carby on it anyway (with a vac port so no need to drill it out) and a TPS without the lever for it. If i changed over to a vac advance dissy would the rattling go away?

 

[whats up]

 

[1985VK]

What RON fuel R U using?
R U running it on a EST Dissy cause You can't adjust the timing to possibly eliminate the pings.

95 but still pings on 98. It does not rattle when it is cold. Yep running it on an EST dissy. It seems it can't advance/retard enough as it should. Without the EGR and a non EST carby on it can't help either with no lever for the TPS.

 

[1985VK]

Can anyone suggest a dissy to suit?

 

[1985VK]

Does it rattle because the EST computer cannot adjust the timing fast enough? Is it a limitation of the computer or because we aren't on super petrol any more?