Fuel heater leak air intrusion?

BlackNoma

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I have had issues with the fuel filter leaking for a while. The lower cap drain valve leaked and I had to put all the beans into screwing it on to seal the top...ish...

After my truck sits for ~10+ hours, the first full minute has amazing power... And then it falls on it's face. The power is kinda like when right before you run out of fuel... But consistent for a whole minute.

I decided to go to a wix enclosed screw on filter with it's own drain and ditch the lower portion. Since doing this, it has more power all the time (much better boost). And the amazing power lasts around 3 minutes, not just 1.
Right after doing this, I noticed the fuel heater leaking out the top. I know how to fix it and will soon.

So, is this an air intrusion issue I have?
Would the heater leak cause the air intrusion?
When I fix the leak am I going to blow my doors off when I get on it?
Or will I just get my mpg's back because I'm not pumping fuel on the ground and whatever weird thing my truck does when it's cold is weird?
 

Thewespaul

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Air intrusion will do that, the injection pump opens the metering valve all the way to purge the air from the system, giving you more fuel than normal operation. Once you have the air intrusion fixed you should have a consistent amount of power again.
 

BlackNoma

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Ok, that's what I thought I was getting, but wasn't 100% sure.
Think it's from the leak in the fuel heater? I have read a lot about fixing them, but none I have read say it fixed an air intrusion.
 

Thewespaul

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I see a lot of leaks there, you will see it leak externally when running and once you shut the truck off it will allow some fuel to drain back and air takes it place.
 

Scooch

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If you see a leak at the fuel heater that's 100% causing air intrusion. Have to fix it and see if the problem goes away. You could have more places sucking air but easiest to eliminate the problem you already know about and go from there
 

icanfixall

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Any fuel leaks make air suck in because of vacuum when the engine shuts down. Think about our fuel systems like a straw. Dip it in soda and place your thumb over the end. Now lift it out. See nothing drips out. Now lift thumb off end see the fluid flow out.Gravity holds the fluid in the straw till you remove thumb that creates the vacuum. Our fuel systems are the same way. Any leaks and the fuel drains back or out ... so now you know..a tight fuel system fires up no matter how long the engine sits not running..
 

Thewespaul

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Great explanation, better than I could do! This is why a lot of people see an improvement on startup times when they put a check valve by the lift pump, it helps prevent the drain back issue when you have any little leak in the fuel system, doesn’t fix the issue but it does help.
 

My1500DollarTruck

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Mine leaked there as well. Seeing your in TX , its about useless . I'm in Ga .. I just pulled the plug and epoxy filled it . No more leak. There are better setups like Racar if you actually need a heater .
 

Justin1574

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I pulled my heater out and tapped the hole with a 1/2 NPT tap, doped a pipe plug and tightened the **** out of it. No more leak there
 

BlackNoma

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I understand how it introduces air while sitting. I was wondering if it did while running. Sorry. I wasn't clear.
Oddly enough, my truck starts up great. Like, way better than any vehicle I have ever owned. Bump the key and it fires off... IDK.

The leak is getting worse, spilling a lot of diesel while ideling. I have a 1/2 not elbow and pressure gauge I plan on putting in after tapping the hole.
I'm excited.

Thanks for y'all's help!
Best diesel/idi site on the webz
 
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