Truck listed above and it stalls when driving

Good evening,

I would start by confirming the compression to be sure the valve timing is correct.

https://www.2carpros.com/articles/car-cranks-but-wont-start

https://www.2carpros.com/articles/how-to-test-engine-compression

Do you have a noid light to see if the ECM is commanding the injectors to fire? try spraying some starter fluid into the air filter and see if it starts and stalls.

Did you verify the spark to the plugs?

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Roy

Clearly fuel pressure is okay, but was this taken during the stall or are you taking this pressure reading when it is just idling? Plus this doesn't eliminate injectors but we can get there if all this checks out.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

So let's just tape the pressure gauge to the windshield and drive it and make sure the pressure is correct.

The fact that it does not restart when hot points to a spark or fuel issue. So let's rule out fuel first.

Next, since you have that scan tool, can you monitor the MAF while driving and then see what it does when it stalls? Clearly once the engine is shut off the air flow will drop but I am just curious what it is doing leading up to the stall. What happens if you unplug the MAF after it stalls? Does it restart?

Let's start with this and go from there. Thanks

Check for spark while cranking.

Let us know about the noid.

Roy

So those MAF readings are not out of line based on the number but the key is to know if it is reading correctly based on the RPM. So let's just prove that out because I am concerned of how it is changing.

Take a look at this attachment. Basically if you don't have a graph feature on the tool then you can do it as they show. Just idle the truck and note the RPM and MAF reading g/s. Then raise it slowly to around 2,500 RPM's and note the MAF reading at about 4-5 intervals.

Then let us know the compression. Also, do you have spark when it stalls and won't restart? We may have a crank sensor issue.

Can you give us the fuel pressure reading while running especially when the engine shuts off? I want to see if the fuel pump is dropping out.

Roy

Fuel pressure is way too low.

Fuel Presure
Key on, engine off .................... 414-448 kPa (60-65 psi)
Engine running .................... 414-448 kPa (60-65 psi)

You need to replace the fuel pump to get the pressure correct.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Roy

Wrench, Fuel Tank Lock Ring
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SPECIAL TOOL(S)

REMOVAL
1. Remove the fuel tank.
2. Clean the area around the fuel pump mounting flange.

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3. Using the special tool, remove the fuel tank pump assembly locking retainer ring.
4. Remove the fuel pump assembly.

CAUTION: The fuel pump assembly must be removed and handled carefully to avoid damage to the float arm and filter.

5. Remove and discard the fuel pump mounting gasket.

Removal

Warning:
Do not smoke or carry lighted tobacco or open flame of any type when working on or near any fuel-related component. Highly flammable mixtures are always present and may be ignited, resulting in possible personal injury.
fuel in the fuel system remains under high pressure even when the engine is not running. Before repairing or disconnecting any of the fuel lines or fuel system components, the fuel system pressure must be relieved to prevent accidental spraying of fuel, causing personal injury or a fire hazard.

1. Relieve the system pressure.

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2. Disconnect the fill pipe main hose.
Loosen the fill pipe main hose clamp.
Disconnect the fill pipe main hose from the main fill tube.

3. Drain the fuel tank.

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4. Remove the four bolts (two each side) and remove the skid plate, if equipped.
5. Support the fuel tank.

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6. Remove the bolts and pivot the fuel tank support straps away from the fuel tank.

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7. Disconnect the fuel pump connector.
Lower the fuel tank slightly.
Disconnect the fuel pump connector.

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8. Disconnect the fuel supply and return line push-connect fittings, the vapor tube and fill tube vent hose fittings at the fuel pump.

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9. Disconnect the vapor line fitting at the rear of the fuel tank.
10. Lower the fuel tank.

INSTALLATION
1. To install, reverse the removal procedure.

Did you graph the crank sensor to watch the pattern?

I know you are checking the mass air flow but that will not cause a no spark issue.

Roy

Okay, I would look in another direction as I suggested.

Roy

Engine speed sensor.

You should have it somewhere that will read engine speed.

Roy

The Crankshaft Position (CKP) sensor is a magnetic transducer mounted on the engine block adjacent to a pulse wheel located on the crankshaft. By monitoring the crankshaft mounted pulse wheel, the CKP is the primary sensor for ignition information to the powertrain control module (PCM). The trigger wheel has a total of 35 teeth spaced 10 degrees apart with one empty space for a missing tooth. The 6.8L ten cylinder pulse wheel has 39 teeth spaced 9 degrees apart and one 9 degree empty space for a missing tooth. By monitoring the trigger wheel, the CKP indicates crankshaft position and speed information to the PCM. By monitoring the missing tooth, the CKP is also able to identify piston travel in order to synchronize the ignition system and provide a way of tracking the angular position of the crankshaft relative to fixed reference (Figure 25).

The crankshaft position (CKP) sensor (Figure 54) is a magnetic transducer mounted on the engine block adjacent to a pulse wheel located on the crankshaft. By monitoring the crankshaft mounted pulse wheel, the CKP is the primary sensor for ignition information to the PCM. The pulse wheel has a total of 35 teeth spaced 10 degrees apart with one empty space for a missing tooth. The 6.8L ten cylinder pulse wheel has 39 teeth spaced 9 degrees apart and one 9 degree empty space for a missing tooth. By monitoring the pulse wheel, the CKP sensor signal indicates crankshaft position and speed information to the PCM. By monitoring the missing tooth, the CKP sensor is also able to identify piston travel in order to synchronize the ignition system and provide a way of tracking the angular position of the crankshaft relative to a fixed reference (Figure 54) for the CKP sensor configuration. The PCM also uses the CKP signal to determine if a misfire has occurred by measuring rapid decelerations between teeth.

I attached the wiring for you to view.

Check for the reference voltage to the sensor.

https://www.2carpros.com/articles/how-to-check-wiring

Roy

You should have resistance between the 2 wires. The resistance comes from the ECM.

It is voltage that counts. When toy test for voltage use the connector. Red lead in one terminal and black on the other and tell me the voltage.

Roy