A&A Twin Pump Fuel System Bleed Down
#1
Burning Brakes
Thread Starter
A&A Twin Pump Fuel System Bleed Down
Good morning everybody. I just recently finished my A&A Vortech V1 install with their behemoth twin pump fuel system. The car runs and drives fine, but when I go to start it, I'm having some cranking issues. I first turn the key to ON and let the pump prime, while watching the FP gauge. It primes up to 58psi, and as soon as the pump shuts off, the pressure drops back to almost 0psi. Then when I try to start the car I have to crank it a couple times, and then try again and it starts. I was under the impression that there was a built-in check valve in the system. Where is this located and does anyone have any idea what might be happening? Like I said, the car runs and drives fine (albeit as fine as it can on a mail-order tune), and the cranking isn't a huge issue honestly; I just want to make sure the car is 100% right before I put her on the dyno. I haven't been into boost at all yet so I don't want this to potentially mess with the twin pumps coming on. Thanks for any advice anyone can give. I'll be sure to call A&A a little later in the day (different timezone and all) to pick their brains. Thanks
Jesse
Jesse
Last edited by LiteraCola; 08-25-2016 at 09:05 AM.
#3
Melting Slicks
There should be a check valve either built in to the external pumps or somewhere on that external line. Give Josh or Andy a call and they will sort it out for you.
#5
Burning Brakes
Thread Starter
That's what I was thinking too. Since there are two feeds, priming the system won't do anything but allow the fuel to flow back to the tank. Weird.
#6
Melting Slicks
Member Since: Jan 2008
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St. Jude Donor '15-'16-'17-'18
Why are the holley's coming on with IGN? Do you not want them on a HOBBS?
There's a check valve in the holley pump assembly to keep it from back flowing. That's the only one.
Where is your fuel pressure gauge sending unit mounted?
I adapted the twin pump from their single pump setup, but it was a few years ago.
There's a check valve in the holley pump assembly to keep it from back flowing. That's the only one.
Where is your fuel pressure gauge sending unit mounted?
I adapted the twin pump from their single pump setup, but it was a few years ago.
#7
Burning Brakes
Thread Starter
Why are the holley's coming on with IGN? Do you not want them on a HOBBS?
There's a check valve in the holley pump assembly to keep it from back flowing. That's the only one.
Where is your fuel pressure gauge sending unit mounted?
I adapted the twin pump from their single pump setup, but it was a few years ago.
There's a check valve in the holley pump assembly to keep it from back flowing. That's the only one.
Where is your fuel pressure gauge sending unit mounted?
I adapted the twin pump from their single pump setup, but it was a few years ago.
#8
Drifting
#9
Drifting
The Holley's aren't coming on with the Ignition. The stock pump is priming as it should, but the pressure drops off like a brick as soon as the pump shuts off. According to A&A, the newer style Holley pumps are designed to not need a check valve, something about the rotors and their close clearances yadda yadda yadda. The sending unit is attached to the regulator under the hood. A&A mentioned taking the regulator apart to inspect the diaphragm, spring, etc, but it's unlikely that there's anything wrong with a brand new regulator. I'm gonna tear it apart when I get the time.
I would suspect a problem with a check valve, or perhaps you didn't get this newly designed pump?
Can you clamp the fuel lines somewhere for a test? Run the pumps with the car off, clamp the fuel line somewhere, turn off the pumps (quickly after the clamp), and see if your pressure bleeds slower.
If it does, you know you need a check valve.
If there is no change with the clamp there, try doing the same thing but put the clamp on the return line. If that fixes your problem, then your regulator has a leak.
Last edited by etekberg; 08-26-2016 at 08:41 AM.
#10
Burning Brakes
Thread Starter
Is your fuel pressure steady with the engine running? If yes, the regulator is probably working.
I would suspect a problem with a check valve, or perhaps you didn't get this newly designed pump?
Can you clamp the fuel lines somewhere for a test? Run the pumps with the car off, clamp the fuel line somewhere, turn off the pumps (quickly after the clamp), and see if your pressure bleeds slower.
If it does, you know you need a check valve.
If there is no change with the clamp there, try doing the same thing but put the clamp on the return line. If that fixes your problem, then your regulator has a leak.
I would suspect a problem with a check valve, or perhaps you didn't get this newly designed pump?
Can you clamp the fuel lines somewhere for a test? Run the pumps with the car off, clamp the fuel line somewhere, turn off the pumps (quickly after the clamp), and see if your pressure bleeds slower.
If it does, you know you need a check valve.
If there is no change with the clamp there, try doing the same thing but put the clamp on the return line. If that fixes your problem, then your regulator has a leak.
#11
Melting Slicks
According to the pictures on A&A website it looks like the check valve is located pre pump. Do you remember seeing one? You could always pull the inner wheel liner and have a look.
#12
Burning Brakes
Thread Starter
#14
Safety Car
Good morning everybody. I just recently finished my A&A Vortech V1 install with their behemoth twin pump fuel system. The car runs and drives fine, but when I go to start it, I'm having some cranking issues. I first turn the key to ON and let the pump prime, while watching the FP gauge. It primes up to 58psi, and as soon as the pump shuts off, the pressure drops back to almost 0psi. Then when I try to start the car I have to crank it a couple times, and then try again and it starts. I was under the impression that there was a built-in check valve in the system. Where is this located and does anyone have any idea what might be happening? Like I said, the car runs and drives fine (albeit as fine as it can on a mail-order tune), and the cranking isn't a huge issue honestly; I just want to make sure the car is 100% right before I put her on the dyno. I haven't been into boost at all yet so I don't want this to potentially mess with the twin pumps coming on. Thanks for any advice anyone can give. I'll be sure to call A&A a little later in the day (different timezone and all) to pick their brains. Thanks
Jesse
Jesse
Our system is seamless and quiet. You’ll never hear the pump as it only comes on under hard throttle conditions, when it’s needed. There is a custom built check valve installed so that the system does not “bleed off” when the car is shut off. This means that the car will start right up after being shut off. Some aftermarket systems bleed the pressure off and require that the starter be cranked for 5 seconds or more to build pressure back up in the lines.
#16
Burning Brakes
Thread Starter
I did. But I jumped the Hobbs switches to run the twin pumps and everything ran fine. If there were trash in the system wouldn't it affect the way the car runs? The pressure stays steady at all times while driving. I only have that trouble on startup.
#17
Drifting
If A&A told you that you don't need a check valve because of a new pump design, that would be where I would investigate first. You could always just put one in anyway, two check valves won't do any harm. You could also run the return line into a bucket and see how much it leaks when the pumps are off. Lots of ways to investigate this problem.
#18
Platinum Supporting Vendor
DO NOT pinch the lines. They are PTFE lined, not rubber.
There is a very fine filter between the tank and the pump. Nothing is going to get through to the pump. The check valve is built into the pump assembly.
I would think it's the regulator. I'm thinking we should just send you a new one to test that theory.
There is a very fine filter between the tank and the pump. Nothing is going to get through to the pump. The check valve is built into the pump assembly.
I would think it's the regulator. I'm thinking we should just send you a new one to test that theory.
#19
Burning Brakes
Thread Starter
Here's an update for anyone interested (or for any future searches where this thread shows up)... I received the new regulator from Andy @ A&A, but before I installed it, I took the old one apart. I found a tiny shard of metal on the seat between the diaphragm and the return port. I cleaned the regulator inside and out with solvent and blew it out with compressed air. I should have reinstalled it to be sure that was the issue, but I installed the new one (after disassembling and cleaning it). I also found metal shards inside the new one!
Andy, if you're reading this, the quality of Holley's machining is definitely lacking. When the regulator was bored for the Inlet ports on both sides, burrs were left and it looked like it wasn't cleaned or deburred at all. Just something you might want to look into.
Anyways, I installed the new one and I no longer have the bleed-down issue. Also, I'm scheduled for Sept 26 with Frost for some dyno time. I'm pretty excited to finally get this car right and feel some BOOOOOST!
Andy, if you're reading this, the quality of Holley's machining is definitely lacking. When the regulator was bored for the Inlet ports on both sides, burrs were left and it looked like it wasn't cleaned or deburred at all. Just something you might want to look into.
Anyways, I installed the new one and I no longer have the bleed-down issue. Also, I'm scheduled for Sept 26 with Frost for some dyno time. I'm pretty excited to finally get this car right and feel some BOOOOOST!