return style fuel system
Thread Starter
Racer
Joined: Jun 2003
Posts: 464
Likes: 0
From: JACKSONVILLE FL
return style fuel system
Finally got my dual in-tank return style fuel system set-up done. Picked it up last weekend, everything seemed to be fine. Except that it would take 1-2 seconds to start-up.
Now my fuel pressure is dropping to 54-55 psi at idle, still strong under acceleration, and is actually reading zero when I shut the car off. When I picked it up, it did not do either one of these things.
Now on top of that, the car is becoming very difficult to start if it sits for more than a few minutes. I would say atleast 4-5 seconds to fire up.
Going to call my installer Monday, but wanted to see what you guys thought.
Now my fuel pressure is dropping to 54-55 psi at idle, still strong under acceleration, and is actually reading zero when I shut the car off. When I picked it up, it did not do either one of these things.
Now on top of that, the car is becoming very difficult to start if it sits for more than a few minutes. I would say atleast 4-5 seconds to fire up.
Going to call my installer Monday, but wanted to see what you guys thought.
Safety Car
Joined: May 2006
Posts: 4,016
Likes: 93
From: St. Louis, MO
Tech Contributor
It's normal for pressure to drop during idle. That's part of a vacuum referenced fuel system. Key on, engine off should read about 58psi. While idling, depending on your cam, you should see anywhere frmo 50 to 55psi. Under boost, it will rise with boost pressure.
The long startup sounds like purely a tune issue unless they didn't install a check valve. Try pushing the start button without having the clutch in, then push the clutch in and hit start again right after it primes.
The long startup sounds like purely a tune issue unless they didn't install a check valve. Try pushing the start button without having the clutch in, then push the clutch in and hit start again right after it primes.
Thread Starter
Racer
Joined: Jun 2003
Posts: 464
Likes: 0
From: JACKSONVILLE FL
Ah, didn't realize lower fuel pressure at idle was normal, it always ran right around 60 psi stock.
Was told a long startup was normal, or atleast wasn't abnormal, but I am just worried that it is taking too long. Started off at 1-2 seconds now takes 4-5 seconds (sometimes).
Anyway to prime the pumps on an auto?
Was told a long startup was normal, or atleast wasn't abnormal, but I am just worried that it is taking too long. Started off at 1-2 seconds now takes 4-5 seconds (sometimes).
Anyway to prime the pumps on an auto?
Thread Starter
Racer
Joined: Jun 2003
Posts: 464
Likes: 0
From: JACKSONVILLE FL
Well, I took the car for a quick trip this morning. The psi at idle was back to running right around 60psi and it was back to only taking 1-2 seconds to fire up.
So my question now is, what are the signs of fuel getting warm?
I didn't have any problems with my car until yesterday(took it to the track for two passes). Would the fuel becoming heated cause these problems?
So my question now is, what are the signs of fuel getting warm?
I didn't have any problems with my car until yesterday(took it to the track for two passes). Would the fuel becoming heated cause these problems?
Instructor
Joined: Jun 2009
Posts: 125
Likes: 0
From: Oklahoma City Oklahoma
lol I have the same issue, with the same setup. But mine won't start if I just hit the start button, but I think my issue is worst because I'm on E85.
I have to get in the car and let the fuel system prime, then bump the starter for just one crank. After that the car will start right up.
I'm going to tie in a push button on the power side of the fuel pumps, so when I'm in the car I can just hit the button to make the system prime longer, I'm thinking that will fix this..
I have to get in the car and let the fuel system prime, then bump the starter for just one crank. After that the car will start right up.
I'm going to tie in a push button on the power side of the fuel pumps, so when I'm in the car I can just hit the button to make the system prime longer, I'm thinking that will fix this..
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Drifting
Joined: Oct 2006
Posts: 1,984
Likes: 16
From: Amityville New York
lol I have the same issue, with the same setup. But mine won't start if I just hit the start button, but I think my issue is worst because I'm on E85.
I have to get in the car and let the fuel system prime, then bump the starter for just one crank. After that the car will start right up.
I'm going to tie in a push button on the power side of the fuel pumps, so when I'm in the car I can just hit the button to make the system prime longer, I'm thinking that will fix this..
I have to get in the car and let the fuel system prime, then bump the starter for just one crank. After that the car will start right up.
I'm going to tie in a push button on the power side of the fuel pumps, so when I'm in the car I can just hit the button to make the system prime longer, I'm thinking that will fix this..
Safety Car
Joined: May 2006
Posts: 4,016
Likes: 93
From: St. Louis, MO
Tech Contributor
Thread Starter
Racer
Joined: Jun 2003
Posts: 464
Likes: 0
From: JACKSONVILLE FL
Burning Brakes
Joined: Oct 2010
Posts: 763
Likes: 2
A lot of fuel pumps, I thought including walbro, prevent backflow even when off. Some regulator will leak down though as well.
Instructor
Joined: Jun 2009
Posts: 125
Likes: 0
From: Oklahoma City Oklahoma
I have twin -8 feed lines. So it would be 2 check valves, but finding a -8 check valve that will work with E85 is the issue. 
The RSI hats do have a built in check valve, but I think it might be to small or something. As for watching the FPR, once the car primes and stops, the fuel pressure goes back to 0.
I have a buddy that is running the same fuel set up as me and on E85.
he wired up his setup to prime all the time if the car is in start, and he never has this issue.
FASTENUF does your do the same?
The RSI hats do have a built in check valve, but I think it might be to small or something. As for watching the FPR, once the car primes and stops, the fuel pressure goes back to 0.
I have a buddy that is running the same fuel set up as me and on E85.
he wired up his setup to prime all the time if the car is in start, and he never has this issue.
FASTENUF does your do the same?
Instructor
Joined: Jun 2009
Posts: 125
Likes: 0
From: Oklahoma City Oklahoma
I have twin -8 feed lines. So it would be 2 check valves, but finding a -8 check valve that will work with E85 is the issue.
I have a buddy that is running the same fuel set up as me and on E85. He was on a BAP, but it burned the power wire to his pump. He is setup now to give the pumps power/prime as soon as the car is in ACC mode, and he does not have this starting issue. This is why I want to tie in a push button on mine, I think the pumps just need to prime a little bit longer then the stock ECU lets them.
The RSI hats do have a built in check valve, but I think it might be to small or something. As for watching the fuel pressure, once the car primes and stops or you turn off the car, both of ours fuel pressure goes back to 0.
FASTENUF does yours do the same?
I have a buddy that is running the same fuel set up as me and on E85. He was on a BAP, but it burned the power wire to his pump. He is setup now to give the pumps power/prime as soon as the car is in ACC mode, and he does not have this starting issue. This is why I want to tie in a push button on mine, I think the pumps just need to prime a little bit longer then the stock ECU lets them.
The RSI hats do have a built in check valve, but I think it might be to small or something. As for watching the fuel pressure, once the car primes and stops or you turn off the car, both of ours fuel pressure goes back to 0.
FASTENUF does yours do the same?
Instructor
Joined: Jun 2009
Posts: 125
Likes: 0
From: Oklahoma City Oklahoma
Thread Starter
Racer
Joined: Jun 2003
Posts: 464
Likes: 0
From: JACKSONVILLE FL
Yep, as soon as the car shuts off, my fuel pressure goes almost instantly to zero.
I did talk to Will about the hard start problem, before it started to take soo long to start. He said that sometimes the fuel will leak out past the regulator, but that it shouldn't all leak out. Should hold a small amount of pressure.
Did talk to my installer about putting in a check valve, but if thats doesn't work, how do you keep it from leaking past the regulator?
I did talk to Will about the hard start problem, before it started to take soo long to start. He said that sometimes the fuel will leak out past the regulator, but that it shouldn't all leak out. Should hold a small amount of pressure.
Did talk to my installer about putting in a check valve, but if thats doesn't work, how do you keep it from leaking past the regulator?
Thread Starter
Racer
Joined: Jun 2003
Posts: 464
Likes: 0
From: JACKSONVILLE FL
What are the effects of fuel becoming too warm??
Took my car out this morning after it sat all night. Fired right up, no delay at all. Unfortunatley after a couple of errands it was back to taking 2-3 seconds to start up.
Took my car out this morning after it sat all night. Fired right up, no delay at all. Unfortunatley after a couple of errands it was back to taking 2-3 seconds to start up.
