weird fuel regulator noise (E85)

[TXEnginerd]

Background: I recently upgraded my lethal budget return system to dual 465s and an -8an feed. Still utilizing stock rails and their frps adapter for the regulator. These upgrades were for E85.

Issue: I'm currently working on perfecting my idle (tuning myself) and during each session I typically load 2-3 new tunes and let the car idle for 5 minutes or so each tune after coming up to temp. After about 10 minutes or so, I start to hear the sound captured in the video below. Fuel pressure reading on the regulator's mechanical gauge drops 2-3 psi from my base of 40 but it doesn't jump around at all. Just a consistent 2-3 psi lower than base. If I pull the fuse on either pump the psi drops a little more but the sound stops but that happens when I disconnect either of them - it's not pump specific. And you can definitely tell the noise is coming from the regulator or where the regulator connects to the rails.

My guess is that the regulator has something wrong with it or the fuel is getting too hot between loading the new tunes and letting the car run. When I come back the next day and first start working on it, the noise is not there. I just don't know if this is a symptom of fuel getting to hot or not.

The car does not actually run any different when this is happening. The AFR is the same but I don't think the injectors are short of fuel at only 2-3 psi lower than what my target is. Also, my electric fuel pressure gauge (at shrader valve location on rails) reads a constant 58 psi regardless of whether this issue is happening or not.

What do you guys think?

[video=youtube_share;OWIklgeepIY]http://youtu.be/OWIklgeepIY[/video]

 

[TXEnginerd]

Fixed the video...

 

[MalcolmV8]

That sounds like there's air in the system. I've heard that sound right after I pulled the tank for some work and got air in the lines. When I first turn on the pumps I hear that same noise for a few minutes till it clears out and goes away. As I recall I even had to go for a drive. It took 10 + minutes to work out. I could actually hear it in the car even at times.
If you've had this going on for a long long time maybe you have a small leak somewhere and it's sucking in air?

Also on a similar note my regulator is mounted to the inner fender/shock tower and I had to put rubber between it and the fender to insulate the noise. I also had to over drill the bolt holes and put rubber grommets in so I had zero metal to metal contact or the pump noise would resonate through the system. Although that's a different sound.

 

[TXEnginerd]

My theory is that at 1/4 a tank or lower, the return line fitting on the underside of the tank is no longer submerged in fuel. So it's just spewing fuel out into the open "air" inside the tank and when it hits the fuel surface, some air is getting picked up by the pumps since that return line is pointed right at the pre-filters inside the oem baffle.

I'm going to re-direct the return fuel line outside of the baffle using submersible fuel hose and nickel plated fittings. I think that will fix the problem.

 

[MalcolmV8]

Makes sense. I never run my tank very low with these 465s anymore so maybe that's why I don't see it. As soon as the needle starts to get below the 1/2 way mark I fill up. Usually takes anywhere from 9 to 11 gallons at that point so I try not to run any lower.

 

[TXEnginerd]

Yeah that's what I'm going to have to do until I have time to try to actually fix it.

While trying to isolate the problem, I noticed that my psi dropped another 2-3 when I unplugged each pump and was only running on 1 pump at a time. Don't you have a controller that keeps your car running on just 1 pump until you get into boost? If yes, have you noticed any issue from the lower base pressure with just 1 pump running?

 

[MalcolmV8]

Yeah that's what I'm going to have to do until I have time to try to actually fix it.

While trying to isolate the problem, I noticed that my psi dropped another 2-3 when I unplugged each pump and was only running on 1 pump at a time. Don't you have a controller that keeps your car running on just 1 pump until you get into boost? If yes, have you noticed any issue from the lower base pressure with just 1 pump running?

Yes I also see a 2 to 3 PSI drop on a single pump. I'm running an Aeromotive FPR. I've been speaking to Fore and they tell me their largest regulator moves such big volume I will not see this 2 to 3 PSI drop. I was thinking about buying theirs and swapping but it's pretty expensive just to test and find out it doesn't fix the issue. So I've been going back and forth on what I want to do. I went ahead and flipped it back to both pumps on but really don't like that because it's moving so much fuel when I start getting close to half a tank of gas I can smell the gas fumes been pushed out of the vent hole by the filler cap because these pumps move so much fuel it's like someone shaking the gas tank and causing pressure and fumes.

I think I'll go back to staging the pumps and just tune it that way. Perhaps just alter the fuel table accordingly if needed. Still pondering the best way to tackle this.

 

[mustang john]

When I did my 465 pumps in my Div X hat I noticed that the return line was dumping right onto the prefilter of one of the pumps, I didn't like that idea so I moved where the return line dumped so it wasn't right into the prefilter and in turn into the pump. I had a feeling that would have aerated the fuel going into the pump and that didn't sit well with me. Isn't the return line also known as a degas line?

My Budget return regulator make a similar noise just not nearly as loud.

I also modded the basket in the tank to aid in refilling it since the large 465 pumps are know to be able to drain the basket quicker than it can refill.

 

[TXEnginerd]

When I did my 465 pumps in my Div X hat I noticed that the return line was dumping right onto the prefilter of one of the pumps, I didn't like that idea so I moved where the return line dumped so it wasn't right into the prefilter and in turn into the pump. I had a feeling that would have aerated the fuel going into the pump and that didn't sit well with me. Isn't the return line also known as a degas line?

My Budget return regulator make a similar noise just not nearly as loud.

I also modded the basket in the tank to aid in refilling it since the large 465 pumps are know to be able to drain the basket quicker than it can refill.

Can you share any details and/or pics of the changes you made?

 

[mustang john]

Can you share any details and/or pics of the changes you made?

I wish i would have taken pics! First i cut the return tube on the Div X hat down to about half the length it come stock then just added a short length of fuel hose so i would have a flexible part to work with. Then i just routed the hose so it returned away from the prefilters and further toward the back of the basket and then zip tied the hose in place to the fuel pumps and hat to hold it securely.

As far as modding the basket first off i had to remove the tube at the bottom to get the hat to sit down flush in the first place, I tried to reposition it but it just didnt flex enough and that tube is damn hard to work with at the bottom of the tank lol! The big Walbro prefilters were hitting the tube and were what was causing me trouble. And on the basket mods I just took a sharp punch and drove about a dozen holes around the top perimeter of the basket to aid in refilling it.

I still dont race with less than 1/2 a tank just for safetys sake.