Fuel tank vent.

Jesse_01 · Aug 20, 2014

When you hear abit of a pressure release when undoing the fuel cap, it is a plugged fuel tank vent. If not unplugged it can lead to low pressure fuel pump failure, fuel guage issues, poor performance, fuel tank collapse and many other issues. Here is what I found when I pulled my fuel tank skid plate off.

I cleared the vent by pulling the rubber plug off and blowing than suction untill the air way was clear.

Spatel23 · Aug 20, 2014

damn....hopefully that answers a lot of your problems

sagebel · Aug 20, 2014

Wow, good to know.

RedRice589 · Aug 20, 2014

Hmmm I think I'll look into that. I run a lot of fuel through mine. Maybe my transfer flow always being open and it's vented is helping

Jesse_01 · Aug 20, 2014

Your transfer flow tank has a vented cap does it not?

RedRice589 · Aug 20, 2014

Jesse_01 said:
Your transfer flow tank has a vented cap does it not?

No there is a screw in vent. I can run a return line to it. I leave it open. Probably not the best idea but it stays clean in there and it's the size of a pen tip for a hole

CoreyMS · Aug 20, 2014

Where's the vent? Got a picture?

Jesse_01 · Aug 20, 2014

CoreyMS said:
Where's the vent? Got a picture?

On top of the tank. Of course I didn't take a pic lol.

Mine only had one vent, this pic shows two. I have the vent at towards the rear of the tank.

I am going to route it to my tidy tank. That way it can vent through a large cap and fuel up itself while I drive.

Jesse_01 · Aug 20, 2014

9A089 is the part number for the vent rubber peice.

BuiltPowerStrokeTough · Aug 21, 2014

I could be wrong here, but I dont know if saying hearing a pressure release noise when removing the fuel cap is a pure indicator of this vent being plugged. Ive owned several different powerstrokes and all of them will make some kind of pressure noise when first removing the fuel cap. This typically happens when youve been running around for a long time and its really hot out, or if you are driving on a long road trip and go to fuel up and release the cap for the first time in 5 hours of the engine running. Glad you found your issue OP and great little right up! Anyone else on here have the pressure release noise driving under the conditions above when releasing the fuel cap but no other issues?

Jesse_01 · Aug 21, 2014

BuiltPowerStrokeTough said:
I could be wrong here, but I dont know if saying hearing a pressure release noise when removing the fuel cap is a pure indicator of this vent being plugged. Ive owned several different powerstrokes and all of them will make some kind of pressure noise when first removing the fuel cap. This typically happens when youve been running around for a long time and its really hot out, or if you are driving on a long road trip and go to fuel up and release the cap for the first time in 5 hours of the engine running. Glad you found your issue OP and great little right up! Anyone else on here have the pressure release noise driving under the conditions above when releasing the fuel cap but no other issues?

I cleared the vent and no more pressure release sound. I can take a video of our other company trucks that are plugged and that aren't plugged.

If you have a system that has negative pressure and the pressure gets released when undoing the cap vs the vent. Wouldn't the vent then be plugged or not working correctly?

carcare · Aug 22, 2014

Normal for fuel tanks to build pressure. It's all got to do with evap system. If u have no pressure when ccv valve closed u will eventually have an engine light and code for evaporative system leak soon. These sensors cycle as needed and on shutdown for the environment

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Jesse_01 · Aug 22, 2014

carcare said:
Normal for fuel tanks to build pressure. It's all got to do with evap system. If u have no pressure when ccv valve closed u will eventually have an engine light and code for evaporative system leak soon. These sensors cycle as needed and on shutdown for the environment

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There is no evap system. Talking diesel not gas.