2nd gen RX7 erratic perfomance problem

[Weaver7]

Steve at what temp will the ECU start pulling back the timing?

Bill Weaver
ITS RX7
#63

[racingralph]

you can start by setting the timing at 28 degees btdc (no more). the sensor (water temp)is set at 170 degees. that one drove me nuts for a few races , replaced it , car went back to running great !

[seckerich]

Normal temp for timing to retard is over 220 usually, but the sensors start to drift and are a big reason some cars loose power in a race. A fresh one and clean contacts in the connector are a good investment if you run a stock computer.

[Weaver7]

If the sensor removed and will this affect the timing....my intial thoughts are no since it isn't reading anything. Does that sound correct?

[Eagle7]

If the sensor removed and will this affect the timing....my intial thoughts are no since it isn't reading anything. Does that sound correct?

Nope. The sensor is a variable resistor in a circuit that is attempting to measure its resistance - normally by using a resistor dividor to convert it to a voltage. Cold = high resistance; hot = low resistance. Not connected = very high resistance.
I don't know the details of the stock ECU, but from a circuit standpoint, disconnected looks like as cold as it gets. It's possible that the ECU recognizes this situation and chooses some default temperature, but it's certainly not optimal.