I just bought a Toyota Camry 1987 sedan, with the 3S-FE engine, and did a diagnostics check, because the engine is idling at 1100 rather than 700, and got an error code 51, the check engine light doesn't come on.

According to the repair manual the Diagnosis is
A/C signal or no IDL signal to
ECU, when engine is idling with
check Terminals TE1 and
E1 connected.

and the trouble area is
A/C switch circuit
A/C amplifier
Throttle position sensor circuit
Throttle position sensor
Accelerator pedal and cable

Well the car doesn't have a/c so we can rule the first 2 out. (unless the a/c was taken out at some point?) How do I know?
The cars accelerator pedal and cable seem just fine, so i assume that it is either the Throttle position sensor circuit or Throttle position sensor.

So I started testing the Throttle position sensor circuit using a voltmeter at the ecu, and go all the relevant voltages.

I wasn't sure whether this only cleared the circuit or the sensor as well so i thought I'd check the Throttle position sensor.

So I worked through how to check the Throttle position sensor according to the repair manual and found that i never got any continuity between any of the terminals, at any of the different throttle position settings.

Does this mean that it is in fact the throttle position sensor that is causing the error code? If so how do i fix it? How do i know that something else is causing the error code as well?

If is is the THROTTLE POSITION SENSOR could it we causing the high idle speed as well or is this another problem?

Any suggestion may help, thanks in advance

will ss

 

Excuse me for being ignorant, but how do you do a diagnostics check?

 

If the car had AC there would be signs such as: switches, etc on the control panel referring to AC, a condenser in front of the radiator, AC compressor pump, AC hoses, etc.

If you have an autotrans, the Park/Neutral switch tells the computer if the trans is in Park or Neutral. The switch is on trans behind the shift lever that the shift cable runs to.

The manual has different data depending on if the car has electronic controlled transaxle or not. If autotrans, does it have electrical controlled shifting?

According to the testing chart only only 2 positions have continuity which are: connections Psw-TL/E1 at full throttle, and IDL-TL/E1 at 0.0197 inch clearance between lever and stop screw.

Some times the engine coolant temp sensor for the computer can fail, causing idling issues.

A diagnostic check for trouble codes can be preformed on cars NOT having ODBII by connection a couple of wired at a electrical plug. This has the computer output any stored codes via the check engine light. The light flashes out the codes. Example, 5 flashes, pause, 1 flash, longer pause = code 51. This code is looked up to find what it means.

 

The car is a manual, how do i know if the car has an electronic controlled transaxle or not?

I have tested both positions but have not gotten any continuity between terminals.

I don't think my car has a ECT sensor.

Any ideas on how to fix the sensor?

 

If stick then there is no ECT or park/neutral switch.

If the car does not have AC this leaves the throttle position sensor.

Might try spraying electrical contact cleaner into the sensor, don't use WD-40.

 

ok ive fixed the throttle control sensor, but the car still idles at 1200 any ideas?

 

error code has gone btw

 

The Intake Air Control (IAC) valve control idle. It might need cleaning. The internet has many posts on how to do this.

Sometimes the water temp sensor for the computer goes bad.

Check for vacuum leaks.