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Is the truck a E85 flex fuel vehicle? Not wanting to start sometimes until you give it wide open throttle means it's getting too much fuel, wide open throttle cuts fuel injectors fuel delivery.
Clear Flood Mode
If the engine floods, clear the engine by pressing the accelerator pedal down to the floor and then crank the engine. When the TP sensor is at wide open throttle (WOT), the ECM reduces the fuel injector pulse width in order to increase the air to fuel ratio. The ECM holds this injector rate as long as the throttle stays wide open, and the engine speed is below a predetermined RPM. If the throttle is not held wide open, the ECM returns to the starting mode.
Do you have a scan tool that can look at live data, fuel trims? Is the ECM adding fuel or taking fuel away. Mass air flow sensor data etc... Flex fuel calibrations may need to be reset .
Starting Mode
With the ignition switch in the ON position, before engaging the starter, the PCM energizes the fuel pump relay for 2 seconds allowing the fuel pump to build up pressure. The PCM first tests speed density, then switches to the mass air flow (MAF) sensor. The PCM also uses the engine coolant temperature (ECT), the throttle position (TP), and the manifold absolute pressure (MAP) sensors to determine the proper air/fuel ratio for starting. The PCM controls the amount of fuel delivered in the starting mode by changing the pulse width of the injectors. This is done by pulsing the injectors for very short times.
Clear Flood Mode
If the engine floods, clear the engine by pressing the accelerator pedal down to the floor and then crank the engine. When the throttle position (TP) sensor is at wide open throttle (WOT), the PCM reduces the injector pulse width in order to increase the air to fuel ratio. The PCM holds this injector rate as long as the throttle stays wide open and the engine speed is below a predetermined RPM. If the throttle is not held wide open, the PCM returns to the starting mode .
You could have a dirty or bad mass air flow sensor .
You could have
On most vehicles there is a wide open throttle cut out switch or it is programmed into the PCM/ ECM . Kills injectors ! To find out if yours has it , try an start the vehicle with gas pedal held to the floor .
You should not need to pump the throttle. That does not have any effect on starting the engine on a fuel injected car.
How do you un-stick the throttle ?
Had a s10 one time and had similar problems turned out after I got rid of it a friend figured it out it was the computer and the Catalac converter how ever you spell it hope this helps Merry Christmas
Wide open as in wide open throttle?? You mean the engine is racing? Something is wrong with the throttle controls, or the throttle valve in the carburetor may be sticking open. Look down the carb throat. At its base will be the throttle valves-"butterfly" valves just like the choke valve on top of carb. The throttle valve should be closed at rest, or at idle, or when gas pedal is not moved. Rotate the throttle lever on the carburetor by hand (when gas pedal is pressed down, the throttle is rotated). The throttle valve at the bottom of the carb should open and close with the throttle lever.
If the valve is sticking, spray some carburetor cleaner down it, and spray the outside clean, too. Work the throttle back and forth to make sure it is free to move.
For a high idle, have the carburetor adjusted. Timing should be checked, too-that can cause a high idle, but wouldn't cause it to go wide open.
Let us know what you find. Good luck.
The only way an engine can run Wide open is if the throttle plate is opened all the way, allowing a large volume of air in to the engine. Check the throttle plate and see if it is hung up or possibly the throttle cable is frayed and holding the throttle open. It is not the injectors, they operate on inputs from the PCM.
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