Step on pedal no throttle pump actuation
This is an injected engine, carbs having gone the way of the horse and buggy, so it has no "throttle pump". I assume by that you meant accelerator pump, which on a carb engine would give an extra squirt of fueldown the carb, when the accelerator was moved, prreventing a hesitation on acceleration. Aside from one old Bosch system on an ancient Volvo, I'm unaware of any passenger car with any additional unit to provide supplemental fuel, except some older systems that employed a cold start valve, for cold enrichment. This being said,one of the duties of the throttle position sensor is to serve notice on the pcm, that there has been an increase in throttle opeming, so in essence, the tps serves as a sort of electronic version of an accelerator pump. You didn't mention codes, so this is where I would start looking. I'm assuming everything else is in reasonable shape. You will need a lab scope or some type of graphing meter, to visually "see" the signal from the tps during operational movement, and look for dropouts and glitches in the signal. Not everyone has access to this type of equipment, so it is possible at some shops, to have the problem diagnosed, for a fee, and then you can perform the repair yourself. Just be sure to let the hard working fellas in the garage know that this is your intent up front, as they will be losing income on repair labor and parts markup, and may have to adjust their fees accordingly. A good wrench that has good diagnostic skills is worth his weight in platinum, and keeping him happy can save you much wasted time, money, and effort. Feel free to get back to me if this does not address your problem directly, and we'll see what we can figure out from there. Thanks, and best of luck!
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The accelerator pedal
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The accelerator pedal position (APP) sensor 1
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The APP sensor 2
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The throttle body assembly includes the following components:
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The throttle position (TP) sensor 1
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The TP sensor 2
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The throttle actuator motor
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The throttle plate
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The engine control module (ECM)
The ECM monitors the driver demand for acceleration with 2 APP sensors. The APP sensor 1 signal voltage range is from about 0.98-4.16 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The APP sensor 2 range is from about 0.49-2.08 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The ECM processes this information along with other sensor inputs to command the throttle plate to a certain position.
The throttle plate is controlled with a direct current motor called a throttle actuator control motor. The ECM can move this motor in the forward or reverse direction by controlling battery voltage and/or ground to 2 internal drivers. The throttle plate is held at a 7 percent rest position using a constant force return spring. This spring holds the throttle plate to the rest position when there is no current flowing to the actuator motor.
The ECM monitors the throttle plate angle with 2 TP sensors. The TP sensor 1 signal voltage range is from about 4.86-0.86 volts as the throttle plate is moved from 0 percent to wide open throttle (WOT). The TP sensor 2 voltage range is from about 0.82-4.14 volts as the throttle plate is moved from 0 percent to WOT.
The ECM performs diagnostics that monitor the voltage levels of both APP sensors, both TP sensors, and the throttle actuator control motor circuit. It also monitors the spring return rate of both return springs that are housed internal to the throttle body assembly. These diagnostics are performed at different times based on whether the engine is running, not running, or whether the ECM is currently in a throttle body relearn procedure.
Every ignition cycle, the ECM performs a quick throttle return spring test to make sure the throttle plate can return to the 7 percent rest position from the 0 percent position. This is to ensure that the throttle plate can be brought to the rest position in case of an actuator motor circuit failure. Observe, under cold conditions, the ECM commands the throttle plate to 7 percent with the ignition ON and the engine OFF to release any ice that may have formed on the throttle plate.
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