Fueling questions

[Randomrunner12]

Hey yall,

can’t find the answer I’m looking for.

This weekend my father and I installed a Fass 165gph along with a Fleece sureflo in tank unit so that I didn’t have to modify or hack up my factory sending unit or cut holes in my tank.

To do this, we removed the bed which was pretty easy actually. Got all fass harness ran and installed, fuel lines installed and both fass and sureflo units. Got all the lines hooked up and fired up the truck per the instructions and no leaks. Put the bed back on and let the truck run for about 10 minutes at idle just to confirm no leaks.

During this install, you have to remove the factory fuel feed line that goes from the tank to the engine filter bowl and then to the CP3. When we did that during install had a bunch of fuel come out of the feed line at the tank due to not being connected anymore which I expected.

What I did not expect was after driving to the fuel station and filling up, I had a massive amount of fuel under the truck, covered the rear axle, undercarriage rear bumper all of it.

Again, feeling where I could from under truck, I found no wet spots anywhere, except where I plugged the factory feed line to prevent dirt and dust getting in it but not tight enough fuel wouldn’t come out.

Can I expect the factory fuel filter bowl to be draining from the feed line now that it’s open and not connected?

 

[petersonj]

Again, feeling where I could from under truck, I found no wet spots anywhere, except where I plugged the factory feed line to prevent dirt and dust getting in it but not tight enough fuel wouldn’t come out.

From looking at your photo, I notice that the plugged fuel line lays right next to the large plastic nut that locks the fuel basket in place. You could have a leak from the fuel basket seal (possibly dislodged during install) and you are thinking it is coming from the plugged fuel line.

- John

 

[Randomrunner12]

From looking at your photo, I notice that the plugged fuel line lays right next to the large plastic nut that locks the fuel basket in place. You could have a leak from the fuel basket seal (possibly dislodged during install) and you are thinking it is coming from the plugged fuel line.

- John

Yes. I’m thinking it’s coming from the plugged fuel line. I can get my hand all the way around the fuel basket ring and it not be wet but soon as I grab the plugged fuel line my fingers a wet and covered in diesel. Unfortunately it’ll have to wait till next weekend when I have more time to investigate.

 

[BigPapa]

So, why the FASS and the Fleece?

You’re not using any of the factory filtration, correct? Where is your injector return hooked up?

 

[Randomrunner12]

So, why the FASS and the Fleece?

You’re not using any of the factory filtration, correct? Where is your injector return hooked up?

Correct, using fass filters now and eventually will use cat or Baldwin
Factory injector return is still hooked up as it should be.

 

[Ozymandias]

How did you put the seal ring in when mounting the sending unit?
The seal ring goes into the opening of the tank first and then the sending unit slides into, easier with some Vaseline around the perimeter.
Putting the ring onto the sending unit and shove it together into the opening doesn't work.
Also there was a break with the 04 to 05, the seal is different.

 

[Randomrunner12]

How did you put the seal ring in when mounting the sending unit?
The seal ring goes into the opening of the tank first and then the sending unit slides into, easier with some Vaseline around the perimeter.
Putting the ring onto the sending unit and shove it together into the opening doesn't work.
Also there was a break with the 04 to 05, the seal is different.

sureflo came with new gasket that looked identical to the factory seal, I installed seal first with no issue putting in the sending unit, put the locking ring on by hand until I couldn’t spin anymore and using a large head flat head and hammer slowly until it stopped spinning. No excessive force installing either so I didn’t break it.

one thing I haven’t checked was the factory fuel bowl to see if it’s still full of fuel or not.

 

[Ozymandias]

Sounds good to me.

 

[AH64ID]

I have to wonder why you are running dual fuel pumps.

One of the only benefits to a setup like the FASS is that the primary filter is under suction, which you have eliminated with your setup.

Be diligent with your filter selection, most of the filters FASS recommends are not rated for 165gph.

 

[Ozymandias]

The Fleece-shurflo isn't a pump, it's just a sending unit with a bucket. I had to look it up too.
Same as a pre-intank pump sending unit, just with a higher flow rate.

 

[Randomrunner12]

OZY and AH64 that’s correct. The sureflo is not a sending unit in itself and has to be used with an aftermarket lift pump such as a fass or air dog.

I could not get ahold of a fleece drop in sending unit to stay as factory as possible but was able to get the fass and sureflo unit for about the same cost from a buddy. Install was rather easy and I having better filtration never hurts.

To comment on my original post. I do believe all my leaking fuel was coming from the factory feed line. Even though it’s plugged it’s not plugged enough to prevent anything draining out. Drove it to work tonight and had barely anything going down the tank and using our shop boroscope was able to get a view above tank and there are no wet spots except the plug on the factory feed.

I’m going to keep an eye on it over the next few days just to be safe and sure otherwise I’ll take the bed back off and drive around a few days so I can see any leaks easier that way.

 

[BigPapa]

Factory injector return is still hooked up as it should be.

The Return Line is connected to the OE Fuel Filter.

 

[bcbender]

The sureflo is not a sending unit in itself and has to be used with an aftermarket lift pump such as a fass or air dog.

I did not need any add on when I put the Airdog on my 04, I removed the pump from the bucket and re-used the OE sending unit with the airdog pulling fuel from the OE bucket and returning to the OE tank line.. it was simple to just remove the electric pump as detailed in Airdog instructions and retained all the original return lines,. I too abandoned the pressure line leading to the tank to the OE filter bucket on the engine and never had any issues with it. I used the Aidog filters and still retained the engine filter as a 3rd check, 195k miles when I sold it and still on the original injectors.

 

[Randomrunner12]

I did not need any add on when I put the Airdog on my 04, I removed the pump from the bucket and re-used the OE sending unit with the airdog pulling fuel from the OE bucket and returning to the OE tank line.. it was simple to just remove the electric pump as detailed in Airdog instructions and retained all the original return lines,. I too abandoned the pressure line leading to the tank to the OE filter bucket on the engine and never had any issues with it. I used the Aidog filters and still retained the engine filter as a 3rd check, 195k miles when I sold it and still on the original injectors.

Air dog has a different style lines than what I can see between them and fass. Either way I think I’ve narrowed it down to just my feed line from the fuel basket, to the filter, to the cp3 being open that it’s just draining fuel. It’s raining really hard here this weekend so I’ll check it Monday or Tuesday when I’m back over at my dads and see what the factory filter bowl looks like then.

 

[Darkbloodmon]

The Return Line is connected to the OE Fuel Filter.

Bigpapa hit the nail on the head I think. Let me just chime in since I've done everything under the sun to my '03 and I've been running this same fuel set up for a while.

For the short sweet answer and solution. The factory injector return line (back of the head) is still connected to the OE filter bowl while you only have the OE feed line(s) capped. Meaning you have fuel being returned to the OE fuel bowl and then over flowing out the capped feed line.

To run this set up you currently have you will need an OE fuel filter bowl bypass block. This will route the OE injector return lines that route back to the OE fuel bowl into you now single return line back to the tank from the engine. You need to remove the OE feed line completely from the system (tank to engine). The OE fuel bowl is a return basin for the injector lines and a feed reservoir.

You should only have one feed line from the fass going to the CP3 directly, one return line from the engine going back to the tank sending unit, and a mass flow return from the fass back to the fuel bucket.

Fleece sells a bypass block if you want to keep everything under the same name.

I'm fairly sure this is your problem, let me know if I get brownie points for being a smart ass.

 

[Randomrunner12]

Bigpapa hit the nail on the head I think. Let me just chime in since I've done everything under the sun to my '03 and I've been running this same fuel set up for a while.

For the short sweet answer and solution. The factory injector return line (back of the head) is still connected to the OE filter bowl while you only have the OE feed line(s) capped. Meaning you have fuel being returned to the OE fuel bowl and then over flowing out the capped feed line.

To run this set up you currently have you will need an OE fuel filter bowl bypass block. This will route the OE injector return lines that route back to the OE fuel bowl into you now single return line back to the tank from the engine. You need to remove the OE feed line completely from the system (tank to engine). The OE fuel bowl is a return basin for the injector lines and a feed reservoir.

You should only have one feed line from the fass going to the CP3 directly, one return line from the engine going back to the tank sending unit, and a mass flow return from the fass back to the fuel bucket.

Fleece sells a bypass block if you want to keep everything under the same name.

I'm fairly sure this is your problem, let me know if I get brownie points for being a smart ass.

Moon, thank you very much for breaking this down and helping me to understand. Then yes, I will need to get a fuel bowl delete block and get that installed so I can remove the feed lines. It doesn’t have to stay fleece so I’ll look around at who’s got what.

as is right now, I’ve run a reattached a factory fuel line connection to the OE feed line and then ran another line to it to a catch can so I can catch what comes out and reuse but it’s not much coming out anymore. I’m about to have another fill up so I’ll also be able to tell if I messed up the in tank pump gasket or not. I don’t think I did but I’ll know tonight when I fill up.

 

[Darkbloodmon]

Moon, thank you very much for breaking this down and helping me to understand. Then yes, I will need to get a fuel bowl delete block and get that installed so I can remove the feed lines. It doesn’t have to stay fleece so I’ll look around at who’s got what.

as is right now, I’ve run a reattached a factory fuel line connection to the OE feed line and then ran another line to it to a catch can so I can catch what comes out and reuse but it’s not much coming out anymore. I’m about to have another fill up so I’ll also be able to tell if I messed up the in tank pump gasket or not. I don’t think I did but I’ll know tonight when I fill up.

Glad to share some insight, keep us posted on the fix.

 

[Randomrunner12]

Glad to share some insight, keep us posted on the fix.

Removed the bed and drove around for a few days. had to zip tie lights to bumper but that's besides the point. Found the leak/spilt fuel to be coming from the factory feed line at the fuel tank where I installed the new sending unit. Since I had basically used a hose clamp and rubber nipple cap, it was keeping dirt out and letting fuel out when truck was pitched up allowing fuel to flow towards rear of the truck.

I realized that because of the way I installed the new sending unit, I had a spare factory fuel line connector, I was able to make a fuel line drain and catch. I've been running that for a couple more days as well and so far no leaks. I think the fuel line was already drained by the time I pulled the bed off again but either way, no more leaking fuel anywhere and truck seems to be running better and idling better.

Due to the amount of minor debris and the fact that the factory pump and screens were all completed coated in crap at only 117k miles, I've decided to go ahead and change the fass filters once just to help and more for my piece of mind than anything.

Thank you all for the help and tips!!!

 

[AH64ID]

What filters did you replace them with?

 

[Randomrunner12]

What filters did you replace them with?

fass again because it’s what I had in the garage. Still need to take some time and cross reference