Anyone running twin Walbro 470 (F9000285) pumps
- Thread starter fordsvtaz
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I run twin 450s with base pressure of 58 PSI, you can run lower if you want to. It just all depends on how much power you are trying to make. What is your power level?
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Im going to be between 900 to 1000hp. So I changed my fuel hat that had the 450hp because it was leaking at the top. Got a new Fore Hat with the 470s, kept base pressure the same, 40psi and my AFRs are 17 to 18 at Idle. Turned it up to 50psi and it drops down to 14 but then back up again to 17.
Have it's been returned since the replacement fuel system parts? That is not than adequate fuel to idle. Something sounds off in the tune or airflow meter.
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I haven't changed anything else. Car ran great right before I put the 470 pumps in. I'm probably just going to switch back.
If you're still returnless the fuel voltage table probably needs to be tweaked as mentioned. If you're return style it's something else.
Something definitely sounds off. Depending on how your tune is set up increasing the base pressure may not lower the AF (make it richer). Some tunes are set up so that the injectors will compensate / adjust as the fuel pressure changes. Something may have gotten goofed up during install.
I think I figured it out. I adjusted my base pressure to 58 and it idles alot better. At 40psi it almost dies.
You shouldn't need to raise the base pressure to get it to idle. There's hardly any load at idle. Even if one pump isn't working the car should still idle at 40psi pressure if that's what its tuned for.
The only thing I did was change out from the F90000274 pumps to the F90000285. I disconnected one pump to see if it would idle and it almost dies. Plus my car is tuned without reading fuel pressure. It was bypassed because I don't have the stock FRPS. I use my AEM guage to read fuel pressure. Guess I'll switch back to the 274s because I know they worked fine.
That shows there's a problem. Either one of the pumps isn't working or the hose is kinked. I can unplug one of my pumps and the car idles fine.
Hopefully the problem is obvious when you drop the tank.
Can't run 450s or 470s returnless.
I knew about the 450's as that's what I'm running. Wasn't sure about the 470's. Mostly trying to cover all bases as the original post was lacking a lot of info.
Edit: Isn't the 470 the Hellcat pump? Aren't those returnless from the factory?
No sure actually, it does have a check valve so maybe. Not sure about Hellcats, aren't Coyote's techincally returnless but it really just returns the extra pressure inside the tank. Haven't looked into many fuel systems beside the 99-04.
Pumps are brand new from Fore. I figured it out. The issue is my stock FRPS is deleted so I need to connect that and revise the tune.
I have a return style system. These are the hellcat pumps. I talked to Walbro and the only difference between these and the 465's is the 470s flow 20% more. I figured out the issue. I deleted my stock FRPS and need to hook that back up so I can adjust the tune.
Were you running the FRPS before? Or did you do it along with the new pumps?
So just thinking out loud. In a return fuel system with a mechanical regulator switching pumps for more or less flow should not require a retune. The lph of the pumps shouldn't matter. The regulator is mechanical and sets the fuel pressure....as long as the tune and install is correct.
Always a good idea to have the frps hooked up in a return style anyway. You can log delta pressure and depending on how the tune is set up can compensate for fluctuations in fuel pressure.
Let us know how it works out.
Always a good idea to have the frps hooked up in a return style anyway. You can log delta pressure and depending on how the tune is set up can compensate for fluctuations in fuel pressure.
Let us know how it works out.
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