What is the idle switch on a 1986 300zx that ecu code 23 refers to?

Year make and model, and have you checked fuel pressure with a gauge ?

Buy a new torque converter before you destroy ******.
Been there.

You may be referring to the fast idle switch. It has a line connected to the ECU. Check also if your idle is constant and not rough. If it is you may want to check the Idle Air Control valve. It may need cleaning or may be bad.

CHECK CAR WITH CODE SCANNER FOR FAULT CODE/OR BRING TO GARAGE TO SCAN CAR FOR FAULT CODE

First thing to determine is if your ecu module ,has the same hardware,software references as your original ecu.If this is the case,and you havent changed anything else,like keys or ignition switch or immobilizer,then it should start!
If ecu doest have same references,you need to have it coded by the dealer,so that it works with your immobilizer.

service manual.
Code Description Possible Cause
0 ECU / ECU signal No signal to ECU
1 Oxygen sensor circuit Oxygen sensor or circuit, ECU
2 Oxygen sensor circuit Oxygen sensor or circuit, ECU
3 MAP sensor circuit Map sensor circuit
4 CKP sensor / engine speed (RPM) Crank angle sensor or circuit, ECU
sensor
5 MAP sensor circuit MAP sensor or circuit, mechanical
problem
6 ECT sensor circuit ECT sensor or circuit, automatic
transaxle control unit
7 TPS / Angle Sensor TPS sensor or circuit, automatic
transaxle control unit
8 CKP sensor / engine speed (RPM) Crank angle sensor or circuit, ECU
sensor
9 CMP sensor CMP sensor or circuit
10 IAT sensor IAT sensor or circuit
11 Idle Mixture Adjuster Sensor Idle mixture adjuster sensor or
circuit
12 EGR system fault No EGR action, faulty EGR valve
13 BARO sensor circuit BARO sensor or circuit
14 Idle Air Control valve circuit / ECU Open or shorted out ignition signal
circuit / No signal to ECU
15 Ignition Output signal Open or shorted ignition output
signal circuit
16 Fuel Injector Circuit Open or shorted fuel injector
circuit
17 VSS circuit VSS sensor or circuit
18 Ignition Timing Adjuster Open or shorted signal circuit
19 A/T Lock-up control solenoid Open or shorted signal circuit,
Lock-up control solenoid lock-up solenoid
20 Electrical Load Detector / Sensor Electrical load detector or circuit
Honda/Acura
Fault Code Definitions (21 - 59)
Chapter 3 22
Code Description Possible Cause
21 Spool Solenoid Valve Open or shorted signal circuit,
spool solenoid valve
22 Valve Timing Electronic Oil Open or shorted signal circuit,
pressure switch valve timing oil pressure switch
23 Knock sensor circuit Knock sensor or circuit
30 AT / ECU communication signal A AT control unit, ECU
31 AT / ECU communication signal B AT control unit, ECU
35 Traction control / ECU / signal Traction control module, ECU
36 Traction control / ECU / signal Traction control module, ECU
41 Oxygen sensor heater - left side Oxygen sensor / heater or circuit
42 Oxygen sensor heater - right side Oxygen sensor / heater or circuit
43 Fuel Supply system - left side Oxygen sensor or circuit, fuel
system
44 Fuel Supply system - right side Oxygen sensor or circuit, fuel
system
45 Fuel metering - left side Injector control circuit, incorrect
fuel metering
46 Fuel metering - right side Injector control circuit, incorrect
fuel metering
48 Heated oxygen sensor Oxygen sensor or circuit
53 Right Knock Sensor Right knock sensor or circuit
54 CKP sensor 2 CKP sensor 2 or circuit
59 CMP sensor 2 CMP sensor 2 or circuit

you will need to do a base idle adjustment bridge the diagnostic pin out and the earth pin out black wire and white and black trace(i think) on the diagnostic connector the engine fan should run at any temp and the check engine light should flash this takes out the ecu operation of the vehicle therefore it will be like a carbie(make sure the vehicle is at or close to operating temp) disconnect the IAC connector then adjust the throttle stop screw to get the right base idle 6-800 rpm while slowly blocking off the iac hole inside the throttle body(may stall a couple of times but persist) with this in mind this is also the way to get flash codes from the ecu just with ignition on terms still bridged first flashes are 10s short break then units eg. two flash=20 three flash after= code 23 long break next code and so on 12 is system ok

25 Automatic Idle Speed (AIS) motor driver circuit shorted or target idle not reached, vaccum leak found 53 Logic module internal problem


have you tried to reboot the ECU by removing the pos battery terminal for a few minutes

2 airflow sensor out of operating range 3 coolant temp sensor out of operating range 4 oxy sensor indicates full rich 5 throttle potentiometer/airflow sensor... (low throttle pot signal with high airflow sensor signal) 6 throttle pot/airflow sensor...... (high throttle pot signal with low airflow sensor signal) 7 throttle pot...idle fuel adjustment failure(idle speed??) 8 intake air temp sensor...open or shorted circuit to sensor 11 Throttle pot at idle: Throttle pot idle trim out of normal range 12 Airflow meter: MAF signal out of range 14 Coolant thermistor: Resistance out of range or static during engine warm up 16 Air thermistor: Resistance out of range 17 Throttle pot: Out of range 18 Throttle pot/Airflow: Low throttle pot signal at high airflow 19 Throttle pot/Airflow: High throttle pot signal at low airflow 22 Fuel pump drive: ECU output to fuel pump relay 23 Fuel supply: Engine running too rich 24 Ignition Drive: ECU output to ignition Amp 26 Air leak: Engine running too lean 29 ECU self check 33 Injector Drive: ECU output to injectors 34 Injector: Looks for Injector dribble 37 EGR Drive: ECU output to EGR switching valve 39 EGR check sensor: EGR not working (normally pipe blocked) 44 Lambda (O2) sensor: Poor mixture control rich or weak (or misfire) 46 Idle speed Control valve: ECU output to Coil AB 47 Idle speed Control valve: ECU output to Coil CD 48 Idle Speed Control Valve: Stepper motor grossly out of position 66 Air pump: ECU output to air pump relay 68 Road speed sensor: Seen speed < 5km/h at high engine airflow 69 Drive/Neutral switch: Seen cranking in "D" or high airflow in "N" 89 Purge Valve drive: ECU output to purge valve
this is all I could find