Fuel pump and P0456
#1
06-12-2016 | 07:28 PM
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Joined: Nov 2011
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From: Calgary, Alberta, Canada
Fuel pump and P0456
My truck is a 2003 QC 4WD with the 4.7 and 545RFE.
Last fall I replaced the fuel pump with a new one from Carter because I was experiencing issues with it getting harder to start, like excessive cranking, when the fuel level would be lower in the tank. Well guess what, it's happening again.
Like before, I've checked the fuel pressure, and it falls within specs when the truck is running. The only downside, then and now, is that when I turn off the engine the fuel doesn't stay pressurized for long after shut off. And if I start it immediately after, it cranks and starts with no hint of over-fueling like if I had a bad injector and it was bleeding down too quick.
One other issue is coming up, and I don't know if it has anything to do with my fuel pump issue. I have been getting a P0456 code since last winter. I have replaced the fuel cap, the hoses in the engine compartment (they actually looked cracked), and the 2 U-shaped hoses down by the leakdown pump. The only hose I haven't changed is the large rubber breather hose coming from the canister. I've cleared the code every single time something was replaced.
Now I noticed today that I am just under half a tank of fuel and if the light was off it would take a little bit of cranking to start it. With the light on it starts like it's supposed to. Now my truck has 314000 kms so it will need more parts as time goes on (looking for another 4.7 or maybe even swap in a Hemi) so I'm prepared to spend a bit on it. This recurring code is starting to **** me off though!
Anyone have any suggestions as to what to look at first?
Last fall I replaced the fuel pump with a new one from Carter because I was experiencing issues with it getting harder to start, like excessive cranking, when the fuel level would be lower in the tank. Well guess what, it's happening again.
Like before, I've checked the fuel pressure, and it falls within specs when the truck is running. The only downside, then and now, is that when I turn off the engine the fuel doesn't stay pressurized for long after shut off. And if I start it immediately after, it cranks and starts with no hint of over-fueling like if I had a bad injector and it was bleeding down too quick.
One other issue is coming up, and I don't know if it has anything to do with my fuel pump issue. I have been getting a P0456 code since last winter. I have replaced the fuel cap, the hoses in the engine compartment (they actually looked cracked), and the 2 U-shaped hoses down by the leakdown pump. The only hose I haven't changed is the large rubber breather hose coming from the canister. I've cleared the code every single time something was replaced.
Now I noticed today that I am just under half a tank of fuel and if the light was off it would take a little bit of cranking to start it. With the light on it starts like it's supposed to. Now my truck has 314000 kms so it will need more parts as time goes on (looking for another 4.7 or maybe even swap in a Hemi) so I'm prepared to spend a bit on it. This recurring code is starting to **** me off though!
Anyone have any suggestions as to what to look at first?
#3
06-17-2016 | 07:14 PM
Captain
Joined: Apr 2016
Posts: 647
Likes: 2
From: Alabama
http://www.obd-codes.com/p0456
The only downside, then and now, is that when I turn off the engine the fuel doesn't stay pressurized for long after shut off.
How quickly does this happen?
The only downside, then and now, is that when I turn off the engine the fuel doesn't stay pressurized for long after shut off.
How quickly does this happen?
Last edited by Friar Tuck; 06-17-2016 at 07:17 PM.