While I was running a single Walbro intank over a 4 month period, I have added a total of 15-20% more fuel to keep it in the 11s so I'm starting to think my Walbro is on its way out the door.

I just installed my inline Bosch 044 and Weldon FPR. Everything starts up and runs great so far, no fuel leaks and nothing out of the ordinary.

I set my base pressure to 50psi once the car was warmed up. After I got done driving for a little bit the base pressure went down to 44-45psi so I set it back to 50psi. I have done this 3 times already and at some point I'm not gonna be able to adjust it. I can still turn the pressure up to 100+ psi which is a good sign I guess.

I did some pulls at 10 psi and it held firm at 60psi fuel pressure which sounds about right for 10psi boost and 50psi base pressure. AF was 11.5 and richened up in the 10s up top which I already adjusted back to 11s. Im just concerned about the loss of base fuel pressure.

1. Does the Walbro work a little less now that the Bosch is Inline feeding the high pressure to my rail?

2. Is it normal for the fuel pressure to drop almost to zero within the first 10 second the car gets turned off?

 

So when you adjusted the base fuel pressure each time, did you see a richer AF mixture each time across the entire rpm range? or was it just that once that you saw it go into the 10's?

 

When I adjusted the fuel pressure, i did a couple runs to make sure my AF was still alright so that I can do my pulls and watch for fuel pressure loss. The reason why it dipped into the 10's was because I added fuel in the tables.

 

I've had 2 walbro's in different cars, and BOTH of them would bleed pressure off once the car was shut off.

You would have to re-prime each and every time the car was started (pressure loss verified through gauge).

Pumps were fine, other than that. I think it's just a design issue.

 

My walbro used to drop pressure after shut off when it was new. But now it will stay at 40 psi for a few hours after shut off.

 

Sounds like that is exactly what is happening but you could also have a problem with the fuel pressure regulator. Are you sure that is does not have a diphram leak?

[QUOTE] I just installed my inline Bosch 044 and Weldon FPR. Everything starts up and runs great so far, no fuel leaks and nothing out of the ordinary.

 

my 044 surge tank setup bleeds pressure instantly with the car off as well, and thats with a OEM fuel pump filling the surge tank, im also using a -8 feed and -6 return running 45ish base psi, i think its normal....

 

As others have indicated, it seems to be normal.

For what it's worth, I have a Walbro with my SOS SC, and mine goes to zero, but not within 10 seconds. I just did a test, but didn't bother to wait until it went to zero but perhaps within a minute, maybe 2?

 

All this sounds great and answers my pressure loss at turn off but what about the resetting of the base pressure? It is a BRAND NEW Weldon FPR and Brand new Bosch 044 so I would like to eliminate the Weldon and Bosch out of this equation.