Yes, the best way to know if your car is closed loop is to follow the gearbox gear position sensor wiring. If the sensor only goes to the gear position display, then the car is definitely open loop. If the sensor is connected to the GCU or the ECU, then it's probably closed loop.
An easier clue: if the car has a separate gear position display that's not integrated into the main dash, it's probably open loop.
An easier clue: if the car has a separate gear position display that's not integrated into the main dash, it's probably open loop.
Both my rental cars have Closed Loop and are equipped with a GPI and GP box (i.e. not in the main dash)...
I'd say the better clue is to check if there is a second TPS sensor on the left side of the throttle body as this is used in closed loop systems (other than systems where it's integrated in the Life ECU) to send throttle position to the GCU.
Hey Nikki, fair enough, though my 2007 SR8 had two TPS sensors and was open loop.
Charley: this seems like a great “ask Phil” question: What was the evolution of the GCUs through the years?
Hey Nikki, fair enough, though my 2007 SR8 had two TPS sensors and was open loop.
Charley: this seems like a great “ask Phil” question: What was the evolution of the GCUs through the years?
I was thinking SR3... Could it be that for the SR8 the ECU needs the input from two TPS sensors (one for each bank) ? I know the throttle bodies are connected so in theory the information from a single sensor should suffice but ???
@nick02 In my case, the car had two (in effect) harnesses. One for the ECU, one for the dash. It was a 2007 SR8, chassis 42. Every bit of data displayed and recorded on the MXL Pista dash came from dedicated sensors, including the throttle opening.
My theory was that Radical hadn't figured out the implementation of the CAN bus interface yet, and so the dash had all its own sensors. But -- who knows? It could have been added by a mechanic along the way too...
@nick02 In my case, the car had two (in effect) harnesses. One for the ECU, one for the dash. It was a 2007 SR8, chassis 42. Every bit of data displayed and recorded on the MXL Pista dash came from dedicated sensors, including the throttle opening.
My theory was that Radical hadn't figured out the implementation of the CAN bus interface yet, and so the dash had all its own sensors. But -- who knows? It could have been added by a mechanic along the way too...
Hi John... Ah yes I remember reading about your car and the fact that my earlier SR3 (we have two) had a similar setup (i.e. separate sensors to feed data to the STACK dash) and which I've now rewired so that the dash reads the CAN bus of the Life ECU ! 🙂
