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I am new to this site and I need some help. I have a 2012 5.7 crewmax that gives me fits on a regular basis on starting. It will crank all day but never wants to fire. It's been to the dealership twice, at first they said it was a problem with the air/fuel ratio at cold start, fixed it, didn't work. Second they said fuel pump was losing its prime, worked fine for a lil while. I was told battery cable ends so I replaced those and it seemed to work for awhile but still yet I'm back at square one. The truck just rolled over 50k miles. Any ideas? I have a video of what the truck does when trying to start but can't figure out how to download. I will get one up soon hopefully.
 

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I am new to this site and I need some help. I have a 2012 5.7 crewmax that gives me fits on a regular basis on starting. It will crank all day but never wants to fire. It's been to the dealership twice, at first they said it was a problem with the air/fuel ratio at cold start, fixed it, didn't work. Second they said fuel pump was losing its prime, worked fine for a lil while. I was told battery cable ends so I replaced those and it seemed to work for awhile but still yet I'm back at square one. The truck just rolled over 50k miles. Any ideas? I have a video of what the truck does when trying to start but can't figure out how to download. I will get one up soon hopefully.
Please start a thread in the New Members Introductions so you can add pics ect. To this thread.

Host your video on YouTube, copy paste link here.
 

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My '14 CM does this. If I turn the key on and let it sit for 5 seconds, it will start every time. Dealer is blaming my CNG system, but there are several posts about this issue. Also my truck doesn't start on CNG. The service departments are becoming an absolute joke.
 

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Hmm. Its a strange deal. When mine first started doing it it only did it when it was freezing outside now it may do it everyday for a week or won't do it at all for 2 months. And yes the service departments aren't doin all they can.
 

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Find the carbon canister purge valve. This is usually located in the engine compartment with a vacuum hose going to the intake manifold. If you obtain a vacuum hand pump and apply vacuum to the manifold side of the valve, you can check and see if it's bad. If it does NOT hold vacuum, such as it leaks down, then it's a bad valve and that is likely your problem. If you find this problem happens immediately after filling the gas tank, then this is most certainly your problem.

Carbon buildup: If you have carbon building up on your intake valves then this will cause a hard start. The fuel injectors spray fuel on the valves and the carbon soaks the fuel up instead of it reaching the cylinders. This condition usually only happens during cold start.
 

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Something similar happened recently to me. Tried 3 dozen times, nothing but cranking. Asked the wife for her key to the truck. Tried it and it started right up like normal.

Wife and I looked at each other and said WTF.

Shut it off and switches back to my key and it started just like it was supposed too. I dunno. The immobilizer just decided to get pissy or something.
 

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Find the carbon canister purge valve. This is usually located in the engine compartment with a vacuum hose going to the intake manifold. If you obtain a vacuum hand pump and apply vacuum to the manifold side of the valve, you can check and see if it's bad. If it does NOT hold vacuum, such as it leaks down, then it's a bad valve and that is likely your problem. If you find this problem happens immediately after filling the gas tank, then this is most certainly your problem.

Carbon buildup: If you have carbon building up on your intake valves then this will cause a hard start. The fuel injectors spray fuel on the valves and the carbon soaks the fuel up instead of it reaching the cylinders. This condition usually only happens during cold start.
I know this is a shot in the dark being a 5 year old post....but I am having "hard start" after filling up. A friend directed me to this purge valve too. Can you briefly explain how filling up the tank causes this? I am ready to spend the $100 on the replacement but am intrigued as to how this happens.
 
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