How does idle speed affect the idle speed?
The largest controlling factor to idle speed is engine throttling. Throttling can come from either the throttle blade itself or the IAC motor. While very large changes can be made to engine torque by changing throttling, actual changes take a relatively long time to fill the manifold and allow the engine to react.
What should idle speed be after camshaft change?
There is no reason to simply increase idle speed from 800 rpm to 1,000 rpm after a camshaft change when a little extra calibration time allows the engine to be stable at 850 rpm. Careful control of fuel delivery, airflow mapping, and spark compensation are the keys.
Why is it important to change base ignition timing at idle?
To prevent stalling in the mean- time, a faster correction to engine torque can be made by changing spark advance. This is why it is desirable to set base ignition timing lower than MBT at idle, leaving room to adjust timing when necessary to reduce speed fluctuations and prevent stalling.
How does the PCM affect the idle behavior of the engine?
The PCM has a number of parameters that influence the idle behavior of the engine. These parameters control the desired idle RPM and the behavior of the Idle Air Control (IAC) motor or Electronic Throttle Control (ETC) during idle conditions.
What should the idle speed be on a GM TBI?
Insert a T-30 size Torx driver into the Idle adjustment screw that is located behind the plug removed earlier. Turn the screw to adjust the idle speed to 650 RPM +/- 50 RPM. Turn off the engine and disconnect the negative battery terminal from the battery using a wrench.
Can a bad throttle position sensor cause idle surging?
Idle surging can be caused due to other issues in the car, but if it happens in conjunction with other throttle position sensor symptoms, the culprit is often the TPS. At idle, the ECM will not get the correct information and the throttle will variate randomly causing idle surges. 3) Check Engine Light
What causes idle surges on a car ECM?
Idle surging can be caused due to other issues in the car, but if it happens in conjunction with other throttle position sensor symptoms, the culprit is often the TPS. At idle, the ECM will not get the correct information and the throttle will variate randomly causing idle surges.
How do you change the idle speed on a T-30?
Insert a T-30 size Torx driver into the Idle adjustment screw that is located behind the plug removed earlier. Turn the screw to adjust the idle speed to 650 RPM +/- 50 RPM. Turn off the engine and disconnect the negative battery terminal from the battery using a wrench. Reconnect the IAC valve.