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I have an issue with my Fuel System Setup. I'm running a Aeromotive Eliminator fuel pump pn:11104 and a Aeromotive Pro Series fuel pressure regulator pn:13110. My issue is when the pump is turned off and the vehicle is not running the fuel pressure bleeds off really quick and when the engine is hot it cause the fuel to vaporize in the lines and loose prime. I check with Aeromotive and there regulators are not designed to hold pressure with the pump off. I do have check valves and have verified it is the regulator bleed off the fuel pressure. Has anyone had any experience with other High Horsepower regulators that do not bleed off pressure?
Hi, I never use Aeromotive though I bought many Essex pumps.
This is the birth place of Aero, check out the Essex site, now divorced.
The design of a regulator is such that a valve/seat is kept closed by the diaphragm spring.
My regulators/pumps all use this design style with pressure direction valve.
You could install an Essex Ejector Pump
You could install an AN check valve just before the regulator.
The feed line going into the regulator is a -10an and the return line is also -10an. both lines to the rails are -8an.
I have the system so it goes from the pump to the regulator first. then the 2 lines come off the regulator to the rails.
Originally Posted by stevieturbo
You're saying the pump loses prime ? Is the pump mounted higher than the fuel level in the tank or something ?
If it is mounted correctly, and below the level of the fuel and gravity fed, it should never lose its prime.
The pump is mounted lower than the tank and its not the fact that the pump lines loose the prime. I have check valves in the feed lines that prevent that from happening. My issue is I've ran my setup a little different. usually most people put the regulator after the rails. My system the main feed line runs to the regulator first with an -10an line. then from the regulator I have 2 -8an hoses that run to the rails. with the regulator not holding pressure with the pump off the heat from the engine causes the fuel in the rails to vaporize and it pushes the fuel out of the -8an lines back to the regulator then back through the return line. My feed line from the pump to the regulator does not loose prime its just the 2 -8an hoses from the regulator to the rails. If I could find a regulator that holds pressure constant like the stock regulators do then I would not have this problem. the areomotive regulator I have bleeds off all the pressure within about 2 seconds through the return line because the diaphragm does not seal off the return side all the way.
Hi, I never use Aeromotive though I bought many Essex pumps.
This is the birth place of Aero, check out the Essex site, now divorced.
The design of a regulator is such that a valve/seat is kept closed by the diaphragm spring.
My regulators/pumps all use this design style with pressure direction valve.
You could install an Essex Ejector Pump
You could install an AN check valve just before the regulator.
The feed line going into the regulator is a -10an and the return line is also -10an. both lines to the rails are -8an.
I have the system so it goes from the pump to the regulator first. then the 2 lines come off the regulator to the rails.
The pump is mounted lower than the tank and its not the fact that the pump lines loose the prime. I have check valves in the feed lines that prevent that from happening. My issue is I've ran my setup a little different. usually most people put the regulator after the rails. My system the main feed line runs to the regulator first with an -10an line. then from the regulator I have 2 -8an hoses that run to the rails. with the regulator not holding pressure with the pump off the heat from the engine causes the fuel in the rails to vaporize and it pushes the fuel out of the -8an lines back to the regulator then back through the return line. My feed line from the pump to the regulator does not loose prime its just the 2 -8an hoses from the regulator to the rails. If I could find a regulator that holds pressure constant like the stock regulators do then I would not have this problem. the areomotive regulator I have bleeds off all the pressure within about 2 seconds through the return line because the diaphragm does not seal off the return side all the way.
Thank you for the replies!
No idea what you're trying to describe.
I run 4 rails, 1 regulator, 2 rails full flow and 2 dead ended. Never in the 7-8 years I've been running it has there been an issue. Nor does the fact the system does not retain pressure after shutdown pose an issue.
What is the actual problem you're trying to "fix" ?
Most aftermarket fuel pressure regulators don't hold pressure like the OEM regulators so it is fairly common for them to loose pressure faster than an OEM regulator (same is true for many of the aftermarket fuel check valves as well). An OEM vehicle is usually held to strict requirements on holding fuel pressure, time to start from cranking etc. Modified and racing vehicles often don't have those requirements.
You can modifiy the Aeromotive regulator and some other aftermarket "racing" regulators to hold pressure better by taking it apart and improving the ball to seat contact but it will still likely leak down faster than an OEM system.
Several companies make adapter blocks that will accept the OEM Delphi, Siemens, Bosch or other fuel pressure regulator cartridges so you can have the types of fuel line connections you want (AN fittings etc.) but still use an OEM type regulator. Lingenfelter had one but it isn't on the web site anymore. Bosch Motorsports has one. Radium makes a few. Here is an image of one they offer:
Originally Posted by boostedLSX
I have an issue with my Fuel System Setup. I'm running a Aeromotive Eliminator fuel pump pn:11104 and a Aeromotive Pro Series fuel pressure regulator pn:13110. My issue is when the pump is turned off and the vehicle is not running the fuel pressure bleeds off really quick and when the engine is hot it cause the fuel to vaporize in the lines and loose prime. I check with Aeromotive and there regulators are not designed to hold pressure with the pump off. I do have check valves and have verified it is the regulator bleed off the fuel pressure. Has anyone had any experience with other High Horsepower regulators that do not bleed off pressure?
The feed line going into the regulator is a -10an and the return line is also -10an. both lines to the rails are -8an.
I have the system so it goes from the pump to the regulator first. then the 2 lines come off the regulator to the rails.
This is part of the problem. You have it plumbed incorrectly.
The regulator is essentially a controlled leak. It releases fuel through the valve when it gets above the set pressure, and maintains the pressure BEFORE the regulator. Everything down stream is not regulated. The only thing holding pressure behind the regulator is the resistance of the system.
This is part of the problem. You have it plumbed incorrectly.
The regulator is essentially a controlled leak. It releases fuel through the valve when it gets above the set pressure, and maintains the pressure BEFORE the regulator. Everything down stream is not regulated. The only thing holding pressure behind the regulator is the resistance of the system.
That's not correct. 99% of all OEM systems are installed with the regulator before the rails.
I'm 1000% sure that 99% is an exaggeration.
Although in the last decade or so, it is very very popular among OEM setups, far less so older cars.
But in reality, the regulator can go almost anywhere in the system as long as it's after the pump. But ideally in a full flow system yes it would be after the rails. But certainly not essential.
That's not correct. 99% of all OEM systems are installed with the regulator before the rails.
Only on a dead head system, like a stock LS1.
Originally Posted by stevieturbo
But in reality, the regulator can go almost anywhere in the system as long as it's after the pump. But ideally in a full flow system yes it would be after the rails. But certainly not essential.
Not exactly true. The regulator is essentially a controlled leak down device. It open and closes a valve based on the pressure it "sees" at the inlet portion. If you were to connect a 1/2 or bigger line to the outlet port and run it to a bucket, you would see almost zero pressure in that return line.
As you've set yours up, the pressure is well regulated between the pump and the regulator - which doesn't mean squat. If you have enough pressure in the fuel rails it's because there is enough or a restriction somewhere to create enough pressure to feed the injectors. But that is unregulated pressure. As demands change, the pressure won't. At some point you'll be fat, and other points you'll be lean.
Not exactly true. The regulator is essentially a controlled leak down device. It open and closes a valve based on the pressure it "sees" at the inlet portion. If you were to connect a 1/2 or bigger line to the outlet port and run it to a bucket, you would see almost zero pressure in that return line.
As you've set yours up, the pressure is well regulated between the pump and the regulator - which doesn't mean squat. If you have enough pressure in the fuel rails it's because there is enough or a restriction somewhere to create enough pressure to feed the injectors. But that is unregulated pressure. As demands change, the pressure won't. At some point you'll be fat, and other points you'll be lean.
It's usually a good idea to read and follow the instructions that come with the parts.
What I stated is exactly true.
What is connected to the return line is irrelevant as long as it does not restrict.
And what is classed as inlet or outlet is very much dependent on how the plumbing is configured. As said....the reg can go anywhere in the system as long as it is after the pump, although that bit is obvious. There are various ways it can all be plumbed and will work perfectly fine.
You are misunderstanding how he has his set up with a dead end in the system.
Although in the last decade or so, it is very very popular among OEM setups, far less so older cars.
But in reality, the regulator can go almost anywhere in the system as long as it's after the pump. But ideally in a full flow system yes it would be after the rails. But certainly not essential.
99% isn't an exaggeration. Most of the high volume cheaper cars all use a returnless system. If you're going by 99% of all make/models, then yes its an exaggeration. I'm talking number of cars on the road.
In most returnless systems, the regulator doesn't even leave the tank. The return is built into the regulator and the fuel returns where it came from without leaving the tank. There is no requirement that the regulator has to be after the rails.
Fuel Pressure Regulators 
