2017 f350 6.7l fuel tank vacuum

Pwrstroke17 · Oct 7, 2019

Been having an issue with my fuel tank creating a vacuum. It happens when towing mostly. Everytime I remove the fuel cap I hear the vacuum.
Any ideas folks?

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sootie · Oct 7, 2019

Is this a problem?

Pwrstroke17 · Oct 7, 2019

Well I don't think it's normal. Not sure if there's any harm either. Here it after a long road trip or hauling the trailer.

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DEEZUZ · Oct 7, 2019

Is it a factory fuel cap?

Pwrstroke17 · Oct 7, 2019

Yes sir factory cap

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SoGrand · Oct 8, 2019

My 17 has done it since day 1 and I have never had a problem. I have 115,000 on it now. I thought it wasn't normal either until I took my first snowmobile trip out west and my other buddy has a 17 also and when we filled up his had the vacuum also so I never thought twice about it after.

lincolnlocker · Oct 14, 2019

sootie said:
Is this a problem?

Wouldnt that make it harder for the lpfp to pull fuel?

live life full throttle

SoGrand · Oct 15, 2019

lincolnlocker said:
Wouldnt that make it harder for the lpfp to pull fuel?

live life full throttle

I would think so also but I have never had a problem with mine and neither has my buddy. After I seen that his did it I never thought about it until this post. We will see if my 2020 does it when I get it in about a month.

Pwrstroke17 · Oct 15, 2019

I've had many of trucks and this is the first one that done this. I seen it before with our f350 gas work trucks when the vent gets plugged.
Don't seem normal to me. Will it hurt idk.

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Cutting-Edge Diesel · Oct 16, 2019

My 2012 does it as well. Never been an issue.

sootie · Oct 16, 2019

lincolnlocker said:
Wouldnt that make it harder for the lpfp to pull fuel?

live life full throttle

no. its perfectly normal.

Pwrstroke17 · Oct 26, 2019

So just for curiosity sake on the way back home from a road trip I pull over and popped the fuel cap off. No codes or issues were encountered doing this. So what I have done now is removed the little rubber seal inside the stock fuel cap. Just popped it apart using a screwdriver. Pulled out the seal and snapped back together. No more vacuum....

Was the tank vacuum hurting...probably not. Gonna run her with a vented cap.

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Zeb · Oct 26, 2019

Pwrstroke17 said:
So just for curiosity sake on the way back home from a road trip I pull over and popped the fuel cap off. No codes or issues were encountered doing this. So what I have done now is removed the little rubber seal inside the stock fuel cap. Just popped it apart using a screwdriver. Pulled out the seal and snapped back together. No more vacuum....

Was the tank vacuum hurting...probably not. Gonna run her with a vented cap.

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Great. Now water and dust can get in around the cap.

Pwrstroke17 · Oct 26, 2019

Not at all worried about that. Water will not get in there. Well I guess if u had the truck submerged under water. But not from normal use. As for the miNute amount of dust that could get in there. Not worried about that either.

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sootie · Oct 26, 2019

Pwrstroke17 said:
So just for curiosity sake on the way back home from a road trip I pull over and popped the fuel cap off. No codes or issues were encountered doing this. So what I have done now is removed the little rubber seal inside the stock fuel cap. Just popped it apart using a screwdriver. Pulled out the seal and snapped back together. No more vacuum....

Was the tank vacuum hurting...probably not. Gonna run her with a vented cap.

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Your a dumb a$s

Zeb · Oct 26, 2019

Pwrstroke17 said:
Not at all worried about that. Water will not get in there. Well I guess if u had the truck submerged under water. But not from normal use. As for the miNute amount of dust that could get in there. Not worried about that either.

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What about when you wash the truck, and you are spraying water around there? Oh wait, maybe you don’t wash it.
The lack of the seal in the cap will more likely cause issues, than leaving the seal in the cap and having that vacuum on the tank ever would have.

Pwrstroke17 · Oct 26, 2019

sootie said:
Your a dumb a$s

Hahaha...and u can *** off. I could give a *** what u think.

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Pwrstroke17 · Oct 26, 2019

Zeb said:
What about when you wash the truck, and you are spraying water around there? Oh wait, maybe you don’t wash it.

The lack of the seal in the cap will more likely cause issues, than leaving the seal in the cap and having that vacuum on the tank ever would have.

Oh I wash my truck. No water is getting in there unless it's done on purpose.

Anyways enough said.

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sootie · Oct 26, 2019

Pwrstroke17 said:
Hahaha...and u can *** off. I could give a *** what u think.

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Expansive vocabulary I must say....

Please don't come on here and complain when you have hpfp problems. Also...if you are so "all knowing" why ask questions in the first place?

Don't let the door hit ya...

Pwrstroke17 · Oct 26, 2019

I'm not gonna get into an keyboard battle here. So enough of that.
Wasn't "complaining" of an issue. Just didn't know if anyone else was experiencing the same thing, apparently people have .
The tank vacuum wasn't giving me any problems. But also didnt know if it was a problem or not.

Regards to the fuel cap mod. It was internal to the cap. can be back to the way it was in seconds.

More curious to c if it throw a code or not.

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