TPS Voltage that ECU says is WOT?

[Viper Driver]

I'm wondering if anyone knows what voltage the ECU changes from closed loop mode (stoichiatric) into open (wide open throttle) mode. The service manual says the TPS voltage should range from 0.5V (throttle closed) to 4.8V (throttle open). Does the ECU wait until 4.8V to go to open loop, or is there a voltage "range" that it uses?

Thanks for the help!

 

[Larry Bastanza]

The ECU also will track manifold pressure, using the MAP Sensor. This will add additional input for the ECU to decide about open/closed loop operations.

HTH,
LarryB

 

[Viper Driver]

Thanks. Yes, that does help. I knew that the ECU uses the MAP voltage for it's A/F calculations, but I didn't know it figured it into the WOT determination.

Anyways, does anyone know the specific voltage/position that the ECU looks for to decide to go into open loop (WOT) mode?

 

[drew]

I'm a Ford EEC IV guy, but I think you need to define the question a bit better

WOT = wide open throttle, your TPS answers that question (max TPS value = WOT)

The open vs closed loop is a different question, I think (Please educate me if I am wrong).

Are you asking:
If, or when or what conditions, does WOT trigger open/closed loop???

Drew

 

[Viper Driver]

I'm a Ford EEC IV guy, but I think you need to define the question a bit better

WOT = wide open throttle, your TPS answers that question (max TPS value = WOT)

Well, I'm not sure, so that's why i'm asking. Does the ECU need the full 4.8 Volts from the TPS as a signal for WOT?

The open vs closed loop is a different question, I think (Please educate me if I am wrong).

It's not really different, in regards to what I'm looking for. Re-phrasing my question.....I need to know if the ECU will trigger open loop at something less than 4.8 Volts, or is there a range of voltages (like from 4.5V up) to allow for tolerances and some "slop"?

 

[Larry Bastanza]

Viper Driver,

I cannot say this for certain, since I really do not know the algorithm used, but I was under the impression that closed loop is used when steady state conditions exist, i.e. criusing on the highway w/static throttle position, idle, etc. I am thinking as soon as you move the throttle position, open loop mode is used.

I say this based on tuning SC cars and using an OBDII scanner and seeing what the 02 sensors do. In closed loop then oscillate up/down around 14.7 to 1 (closed loop). I only have observed that in steady state conditions. I am talking about conditions where boost is not a factor, obviously in boost you are in open loop.

Sorry I am not really answering your question, but I am not sure there is a direct correlation between the TPS voltage(or range) and open/closed loop mode being used.

HTH,
LarryB