Rick's Free Auto Repair Advice

Hard start when cold Ford

Diagnose and fix a hard start when cold condition Ford

The hard start when cold problem

If you have a Ford vehicle and find that has a hard start when cold condition, here are the common things to check. The issue appears as an engine that will crank but has a hard time firing up. Once it does start, it doesn’t run well. It may run extremely rich, which you will notice with rough idle and poor MPG. It may also store trouble codes P0172 and P0175. However, once the engine warms up, it runs fine and will restart just fine.

P0172 – System Too Rich (Bank 1)

P0175 – System Too Rich (Bank 2)

This Ford shop manual says these kinds of hard start when cold problem can be caused by:

Possible causes of hard start when cold

Leaking fuel injectors

Fuel return line restricted

Fuel rail pressure (FRP) sensor bias

EVAP purge valve is leaking when the canister is full

Most common cause of hard start when cold

If you own one of these vehicles, skip the above checks and start by testing fuel pressure. See this post on the fuel pressure test procedure

2010 Expedition 5.4

2011 Expedition 5.4

2011 F-150 3.5

2011 F-150 3.7

2010 F-150 5.4

2011 F-250 Super Duty 6.2

2012 F-250 Super Duty 6.2

2013 F-250 Super Duty 6.2

2014 F-250 Super Duty 6.2

2015 F-250 Super Duty 6.2

2011 F-350 Super Duty 6.2

2012 F-350 Super Duty 6.2

If you have access to a scan tool, check the FLEX FUEL DATA reading. If the reading is 70% or higher, your first job is to reset the PCM by disconnecting the battery terminals for at least 5 minutes. Then reconnect and take the vehicle for an extended road test. Let the vehicle cool until the engine is cold. Then perform a cold start test.

If you encounter the same hard start when cold and the FLEX FUEL DATA reading is back up to 70% or more, your next step is to check fuel pressure.

Check fuel pressure.

See this article for help in locating the fuel pressure test port

Fuel pressure must be at least 55-60-psi. If pressure is 50-psi or less, that would cause this problem. Here’s why. Normally, low fuel pressure would cause a LEAN condition. However, when fuel pressure is low, the PCM sees the lean condition and initiates a FLEX FUEL LEARN routing, thinking that you’ve filled the tank with E-85, which has lower Btu’s. This procedure actually results in a RICH condition.

Fix for hard start cold

Replace the fuel pump if fuel pressure is less than 50-psi

Ford fuel pump

Ford fuel pump module

©, 2017 Rick Muscoplat


Posted on by Rick Muscoplat

Custom Wordpress Website created by Wizzy Wig Web Design, Minneapolis MN