MARK3 ,sometimes hard to start, idle rpm not stable.

[cre]

You MUST insert a jumper across T(E)1 and E1 in the diagnostic box when setting/checking the timing. Additionally, NO CODES can be present, the throttle MUST be fully closed and the A/C MUST be off... and the engine needs to be at normal operating temp. The timing is supposed to be at 10 degrees BTDC, the ECU will advance it further based on sensor feed back, it's not an old Chevy, advancing it further yourself will actually do NOTHING.

Here's the process from the Toyota Service and Repair Manual:
http://www.cygnusx1.net/Supra/Librar...aspx?S=IG&P=20

And yes, from a cold start the car will usually be quite rich... it runs richer on purpose.

[chinesedawn]

I adjust the timing today, but I adjust the timing at 860 rpm not 700 rpm( it is the lowest rpm) , the engine runs really good now ,idle rpm stable at 1000 rpm, but I get a new DTC.....Which is #51( Switch Signal, No "IDL" signal, "NSW" signal or "A/C" signal to ECU, during diagnosis check )

No code Yesterday but #51 DTC show up today when I start the car. You said no code can be present when adjust the timing so I don't know if is OK or I should find out what is the problem and how can I do the Diagnosis.

Oh yeah other than this, my car's gas pedal has about half inch free play and not very sensitive, always take about half second to raise the RPM after I depress the gas pedal, is this normal?

[cre]

Code 51 will occur if:

the throttle is pressed while in diagnostic mode or there is a problem with the IDL switch in the TPS

the A/C is on while in diagnostic mode

an automatic vehicle is not in Park or Neutral or the Neutral Start Switch is defective


All of these will cause idle problems and timing can not be set with any of these problems present.


EDIT: check the throttle cable for excessive play... AFTER you fix the other problems. The TSRM covers adjusting it.

[chinesedawn]

Quality！ So how can I check the "idl" at TPS and what is the full name of "IDL"?? I remember there are 4 terminal at the sensor.

[cre]

http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=101

IDL is the full name, it's not an acronym. It's a signal line which the ECU monitors so it knows if the throttle is truly closed as opposed to relying solely on the TPS voltage.

[chinesedawn]

I change the radiator today,after I put the new one in I did a test drive on the high way, but the coolant temperature goes high after 9 min about 60 miles/hour so I shut it down and restart it again, the Tem. drop to half and when I start drving it, Temperture goes high again and I DON'T have heater, I used to,I have heater before I change the radiator.

I touch the radiator, it's hot so it means the thermosta is good but the problem is the coolant in the raservior is cold....