Please Consult with our GMTN Expert on PID Designs for OBD2 Scanners and Blue Tooth Device:
@TJBaker57 ...as he is very capable of guiding you towards how they need to be set up to observe and break down these Sensor-Module Data Elements and make good sense of things.
The "Winning Combination" for problems of
Controlling Air Flow in a Modern Motor that simply responds to how well that AIR is controlled versus one that uses Fuel Delivery via Carburetor Fuel Spray. These are the Main Players required to make it all work:
(1)
MAF (Mass Air Flow) Sensor WITH
IAT (Inlet Air Temperature).
This primary metric works by WEIGHING THE INCOMING AIR STREAM in Grams. The technique works better than any other Method because it is NOT Affected by Altitude causing Lower than Sea Level Air Pressure... say while driving up to Pike's Peak vs. riding along the New Jersey Shore of the Atlantic Ocean. The MAF sensing mechanism informs the PCM constantly with data about "What the In-Coming Air Weighs at Varying Temperatures" to provide the PCM with that portion of what it adds to the Fuel Delivery Algorithm.
(2)
The Oxygen Sensor(s) Four for V8s...2 for the I-6 Engines.
The Heated Oxygen Sensors role is to use a shielded Cubic Zirconia Sensor poking its "Thumbs" into the Exhaust Streams and simply measures the presence of Excess Oxygen. This device is considered "Narrow Band" because it only uses the "Perfect Stoichio-Metric" reading of 14.7:1 for the Air to Fuel Ratio. Oxygen Sensors Do NOT measure the presence of Un-Burned Gasoline within the Exhaust Stream. It only provides the information on the "Left Over" Oxygen discarded from improper combustion F/A ratios happening well ahead of it. The O2 Sensors provide this data to the PCM to be added into the PCM Fuel Delivery Algorithm. The Aft Oxygen Sensor data stream alerts the PCM as to efficiency of how well the Catalytic Converter is chemically converting the by-products of incomplete Engine Combustion into less Noxious or Polluting Vapors along with Water as by-products of combustion.
(3)
The Throttle Position Sensor (TPS.
The Throttle Position Sensor on modern EFI Engines controls and meters the In-Coming Air Stream using a 12 Volts DC Motor and Nylon Gear Reduction Mechanism set up to provide very fine Electro-Mechanical control of the position of the Butterfly Plate that either Opens or Closes to deliver More or Less Air on Demand and informs the PCM by means of its PWM (Pulse Width Modulation) to control the Drive Motor to Plate movements with Very Fine Movements. Along with controlling this activity via PWM., the PCM is capable of Reading the Angle of the Butterfly Plate moment by moment and thereby adds that information into its Fuel Delivery calculus having figured out what the Weight and Temperature of the In-Coming Air is up to that point and adds that information to its Fuel Delivery Algorithm from (Fuel-Air Tables) stored in Memory.
(4)
The Accelerator Pedal Module (Accelerator)
The "Gas Pedal" in modern EFI Fuel Air Engines is anything but... It is more akin to having Two Potentiometers that measure in Milli-volts (mV) on Two Separate Channels communication with the PCM and the Throttle Body. This means that as the "Gas Pedal" gets Pushed Down... One signal in Milli-voltage (mV) Decreases while the other Increases. Likewise, when the Gas Pedal is released, these two PWM Monitored (mV) signals get sent to the PCM... and provide Opposite mV Values for referencing. In this manner, the PCM can use this combination of the Position of the Gas Pedal AND the Angle of the Throttle Body Butterfly Plate to determine the INTENT of the Driver to want More Power from the Motor... and that leads to the next Major Player in this Drama...
(5)
Electronic Fuel Injectors (EFI)
The GM Multec II Design of the EFIs provides the ability for the PCM to vary its Pulse Width Modulation (PWM) and change whether the (6) EFI Pintle (Pintel) Valves are either Open or Closed ...and even more importanly...for How Long in order to achieve more Time based subtlety in How Much Fuel is being Atomized into a Mist per Cylinder with greater or lesser intervals to either increase or decrease the Amount of Fuel that is available at varied RPM and Engine Power Band requirements. The Fuel Rail provides adjustable pressure via the responsive Fuel Pump to ensure that the Fuel Pressure does not drop below an acceptable level via the PCM providing (PWM) responding signals to it as well to raise or lower its RPM.
(6)
The Vehicle Speed Sensor (VSS)
To a Greater or Lesser degree... The 4L60E Hydro-matic Transmission requires regular PCM input in order to know at what particular RPM it needs to Shift Gears into (or PREVENT any Gear Shifting) to provide the proper PRNDL123 Gearing depending upon the need for Power being fed by the Engine into the Torque Converter. The PCM uses Pulse Width Modulation to signal the Solenoids inside the Transmission to move either up or down in the internal Gear Ratios and achieve a balance of Power Needs vs. Power Delivery
(...and not Destroy the complex Gear Box inside by accidentally Down Shifting at Highway Speeds)
I'm probably missing quite few other Engine Air/Fuel Regulatory Modules... but THESE are the main Players to be considered in any instance of the engine suddenly misbehaving or going into either Reduced Power or Limp Home Mode as a precaution necessary to prevent the Accidental Runaway of an Engine OUT OF CONTROL.. Should any of these F/A Delivery Mechanisms FAIL.