Hard to start when cold, starts fine when warmed up

Hi,

The first thing I would suggest (if the check engine light stays on with the engine running) is to check for diagnostic trouble code. Here is a quick video showing how it's done:

https://youtu.be/YV3TRZwer8k

I realize most people don't own a scanner. However, most parts stores will scan it at no charge or lend you a scanner.

Next is the engine coolant temperature sensor. If it is sending a wrong signal to the computer, the fuel mixture may be too lean or too rich to start it. Again, to check that requires a live data scanner. If you have one, check what temp signal the ECT is sending to the computer and make sure it is withing reasons in comparison to ambient temps.

If that checks good, reconfirm fuel pump pressure. It could still be low. I doubt that is the issue, but it can be.

Do these things and let me know what you find. If you have no access to a scanner, let me know that as well.

Take care,
Joe

Does the smoke come from the exhaust? What color does it appear to be? And no problem with when you get to it. I'll be here.

Let me know.
Joe

Okay. Chances are it is steam from the exhaust and nothing more. However, the hard cold start can be the temp sensor or low fuel pressure among other things. Since it started when it got colder, I have a feeling it is related to the sensor.

Regardless, let me know.

Joe

Okay, then we need to confirm fuel pressure and see if it is dropping off and causing the hard start. Here is a link that shows how it is done.

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

Here are the directions specific to this vehicle. I have a feeling the fuel pressure is low at first when starting and then okay after you get it going. The attached pics correlate with the directions.

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2010 Ford Truck F 150 4WD V8-5.4L Flex Fuel
Fuel System Pressure Test
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Fuel Pressure Testing and Inspection Component Tests and General Diagnostics Fuel System Pressure Test
FUEL SYSTEM PRESSURE TEST
310-00 Fuel System †General Information 2010 F-150
GENERAL PROCEDURES
Fuel System Pressure Test

Special Tool(s)

pic 1 Fuel Pressure Test Kit

310-D009 (D95L-7211-A) or equivalent

pic 2 Fuel Pressure T-Adapter 3/8"

310-D252 or equivalent
image WARNING: Do not smoke, carry lighted tobacco or have an open flame of any type when working on or near any fuel-related component. Highly flammable mixtures are always present and may be ignited. Failure to follow these instructions may result in serious personal injury.

image WARNING: Before working on or disconnecting any of the fuel tubes or fuel system components, relieve the fuel system pressure to prevent accidental spraying of fuel. Fuel in the fuel system remains under high pressure, even when the engine is not running. Failure to follow this instruction may result in serious personal injury.

image WARNING: Do not carry personal electronic devices such as cell phones, pagers or audio equipment of any type when working on or near any fuel-related component. Highly flammable mixtures are always present and may be ignited. Failure to follow these instructions may result in serious personal injury.

image WARNING: Always disconnect the battery ground cable at the battery when working on an evaporative emission (EVAP) system or fuel-related component. Highly flammable mixtures are always present and may be ignited. Failure to follow these instructions may result in serious personal injury.

image WARNING: When handling fuel, always observe fuel handling precautions and be prepared in the event of fuel spillage. Spilled fuel may be ignited by hot vehicle components or other ignition sources. Failure to follow these instructions may result in serious personal injury.

pic 3

If servicing a 4.6L (3V) engine, remove the Evaporative Emission (EVAP) purge valve bracket bolt and position the bracket aside.

pic 4

If servicing a 5.4L (3V) engine, remove the air intake resonator assembly bolt and loosen the clamp. Rotate the resonator upward until it stops.

pic 5

NOTE: 4.6L (2V) shown, 4.6L (3V) and 5.4L (3V) similar.

Remove the fuel pressure relief valve cap.

pic 6

NOTE: 4.6L (2V) shown, 4.6L (3V) and 5.4L (3V) similar.

Install the Fuel Pressure Test Kit onto the fuel pressure relief valve.

pic 7

NOTE: It may take more than one key cycle to pressurize the fuel system.

Cycle the ignition key to the on position and wait 3 seconds to pressurize the fuel system. Check for leaks before starting the engine.
Test the fuel system pressure to make sure it is within the specified range. For additional information, refer to Specifications in this section.
NOTE: 4.6L (2V) shown, 4.6L (3V) and 5.4L (3V) similar.

NOTE: Open the drain valve slowly to relieve the fuel system pressure. This may drain fuel from the system. Place the fuel in a suitable container.

Upon completion of the fuel system pressure test, open the drain valve on the Fuel Pressure Test Kit and relieve the fuel system pressure.

pic 8

NOTE: 4.6L (2V) shown, 4.6L (3V) and 5.4L (3V) similar.

Install the pressure relief valve cap.
Tighten to 6 Nm (53 lb-in).

pic 9

If servicing a 4.6L (3V) engine, position the EVAP purge valve into place and install the bracket bolt.
Tighten to 10 Nm (89 lb-in).

pic 10

If servicing a 5.4L (3V) engine, rotate the air intake resonator assembly into position and install the bolt.
Tighten to 10 Nm (89 lb-in).

pic 11

6.2L (2V) engine

Release the fuel system pressure. For additional information, refer to Fuel System Pressure Release in this section.
Disconnect the fuel tube quick connect coupling. For additional information, refer to Quick Connect Coupling in this section.
Install the Fuel Pressure T-Adapter 3/8" and Fuel Pressure Test Kit in line between the fuel supply line and fuel rail.

pic 12

NOTE: The Fuel Pump Control Module (FPCM) electrical connector was disconnected during the fuel system pressure release and must be reconnected to complete the Fuel System Pressure Test.

Connect the Fuel Pump Control Module (FPCM) electrical connector.
Connect the battery ground cable. For additional information, refer to Section 414-01 .
NOTE: It may take more than one key cycle to pressurize the fuel system.

Cycle the ignition key and wait 3 seconds to pressurize the fuel system. Check for leaks before starting the engine.
Test the fuel system pressure to make sure it is within the specified range. For additional information, refer to Specifications in this section.
NOTE: Open the drain valve slowly to relieve the fuel system pressure. This may drain fuel from the system. Place the fuel in a suitable container.

Upon completion of the fuel system pressure test, open the drain valve on the Fuel Pressure Test Kit and relieve the fuel system pressure.
All engines

NOTE: It may take more than one key cycle to pressurize the fuel system.

Cycle the ignition key to the ON position and wait 3 seconds to pressurize the fuel system. Check for leaks before starting the engine.

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Pay attention to fuel pressure drop off. That is when you turn the key off. I would recommend doing this when the engine is cold and will have the conditions indicated.

Let me know if this helps or if you have other questions.

Joe

The 15 psi on the first turn is low. Do me a favor. Cycle the key from off to on (run position engine off) three times. On the fourth time, see if it starts easily. Pressure with the engine running should be between 55 and 60 psi.

See if cycling the switch helps it cold start.

Let me know.
Joe

Hi,

Something is allowing pressure to bleed off. It could be a leak or an injector. Now I'm basing that on the fact that you just replaced the pump and so on. I do have a concern regarding what you said about the white smoke that doesn't appear to be water vapor. White smoke is usually associated with coolant entering the combustion chamber as a result of a head gasket issue or other internal issue. Can you record upload when you see the smoke so I can see what is happening?

Now, since it did start with cycling the switch, we really need to confirm that at a cold start, pressure is low. I recommend following the directions for testing fuel pressure I listed first. You may just have a weak pump.

Also, here is a link that explains how to check for a bad head gasket. I don't think this is the issue, but in one way it could be. When the engine is cold (after sitting) steel contracts. That can cause lower compression or allow a gasket to leak. After it warms up, the steel will expand, possible sealing off any issues. Truthfully, that is really a long shot. I only mention it because you said about the white smoke.

https://www.2carpros.com/articles/head-gasket-blown-test

Check to make sure the coolant level isn't down and let me know what you find.

Take care,
Joe

The idle could be a result of pressure as well. However, there is what is called and idle air control valve (IAC) that can cause that to happen. The IAC is located on the throttle body and maintains the engine idle speed. Basically, it allows air to enter the engine when the throttle plate is fully closed.

Just for the heck of it, try cycling the key for a couple days to see if it consistently allows the vehicle to start easier. If it does, then perform the pressure test. The truck has a returnless system, so there could even be an issue with the fuel line pressure sensor on the rail.

Like you said, a pain in the wazoo. LOL And the worse news is, they just keep getting more and more complex. Ugh!

Take care and let me know what you find.

Joe

Retirement? Congrats!

Okay, I need you to check a specific fuse in the battery junction box. It is fuse 27. Do me a favor, pull it and inspect the fuse as well as the socket it goes to. I remembered reading about an issue with them overheating and causing hard start or no start conditions. See pics 1 and 2.

Let me know.

Joe

If you have 12v at the socket, then either the pump is bad or something is causing a restriction.

At this point, I would check to see if pressure is good right at the module. If it isn't, the pump has a problem. If it is, then there is a restriction at some point.

Joe

Take a look through this info and let me know your thoughts. In most cases, the injector pump either works or it doesn't. I guess it's possible that we have a new type of issue. However, you are checking fuel pressure before this component. Once the engine starts, the fuel injection pump increases pressure. That is why I don't feel it is related.

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2010 Ford Truck F 150 4WD V8-5.4L Flex Fuel
High Pressure Fuel System
Vehicle Powertrain Management Computers and Control Systems Testing and Inspection Diagnostic Trouble Code Tests and Associated Procedures Powertrain Control/Emissions Diagnosis (PC/ED) Section 1: Description and Operation High Pressure Fuel System
HIGH PRESSURE FUEL SYSTEM
2010 PCED Gasoline Engines
SECTION 1: Description and Operation
High Pressure Fuel System
Overview
The high pressure fuel system receives low pressure fuel from the fuel pump module and delivers fuel at high pressure to the direct injection fuel injectors.

The high pressure fuel system consists of the fuel injection pump, the fuel volume regulator, the fuel rail pressure (FRP) sensor, the fuel supply line, the fuel rail, and the fuel injectors. For additional information on the fuel system components, refer to Engine Control Components in this section. Operation of the system is as follows:

1) The fuel injection pump receives fuel from the fuel pump module, increases the fuel pressure from approximately 448 kPa (65 psi) to a PCM determined pressure up to as high as 15 MPa (2175 psi), and delivers it to the fuel rails.

2) The fuel volume regulator controls the volume of low pressure fuel that enters the inlet check valve and the pump piston inside the fuel injection pump. The PCM regulates fuel pressure by controlling the timing of the fuel volume regulator solenoid.

3) High pressure fuel exits the fuel injection pump and is delivered to the fuel rails through the fuel supply line.

4) The fuel rails distribute and channel high pressure fuel to the fuel injectors.

5) The FRP sensor provides a feedback signal to indicate the fuel rail pressure so the PCM can command the correct injector timing and pulse width for proper fuel delivery at all speed and load conditions.

6) The fuel injectors meter fuel flow to the engine. A given cylinder fuel injector can deliver single or multiple injections for each cylinder event. The amount of fuel is controlled by the length of time the fuel injectors are held open.

Pic 1

High Pressure Fuel System

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The other thing is the fuel pump control module. It may not be working properly, but then you wouldn't have 12v right away to the pump.