Ok my friend has an 08 ls3 vette..
I left the stock fuel system and tapped the drivers side bottom tank with a -8 line going to a bosch 044 fuel pump with a filter before and after the pump, and a -8 going to a t-fitting with the stock feed at the rail, and a boost referenced regulater and -6 return going back to driver side tank..

I wired in a hobbs switch to turn on the bosch pump, after I completed install of my new system I jumped out hobbs switch and bosch pump came on and everything was good, the hobbs switch I used I had laying around and I thought it was a 4psi NO switch but turned out it was a 50psi NO so when I made a pull my injector duty cycle shot up to about 500%, ordered the right hobbs switch and start making pulls and the same problem, so now I jump out hobbs switch again and no fuel pressure however I feel and hear the bosch pump running which is attached to the rear subframe, but it is noticeably quieter than b4.....

So my friend brings his car to my house so I could pull the bosch pump and filters to inspect and he tells me the car was running real ****ty once he got about a block away from my house, and he goes to start it now in front of my house and there's no fuel pressure, I jump the factory fuel pump relay and still nothing and fuse is fine, so I pull the bosch pump and filters and everything seems fine accept the drivers side gas tank is empty, so I figured that explains our problem, eventhough his car said it had 1/2 tank, and he never had this problem until now.

I put everything back together push car to gas station and fill it up and it only takes 10gallons which means how could have it been empty lol, so now were just confused lol, but we proceede to start car and it fires right up good fuel pressure and all, however the bosch pump still has the same issue now...

So I would say that it is possible that the bosch pump could have gotten fried when we jumped it out and there was no fuel even though it was only for about 20 seconds, but it still turns on and all, just not as loud as it was the first time and its not creating fuel pressure.....and how the stock pump system ran outta gas when the gauge read 1/2 tank and it only took 10 gallons to fill tank

If anyone can think of something logical please contribute thanks

 

...just a piece of the puzzle but if your car reads half full and the driver's side tank is dry that means everything is in the passenger side tank. The venturi pump in the passenger side which needs the fuel pressure from the powered pump in the driver's tank to function isn't pumping fuel back over to the driver's side thru the crossover tube. Something you have done with the fuel pump install has screwed things up.

Study this link to understand how the base fuel system works. It will help with your troubleshooting.

http://www.corvetteactioncenter.com/...el+Tank+System

 

Next I'd pull and isolate the Bosch pump and get a pressure gauge on it. You need to see whether you still have a good pump or if running it dry has turned it into a paper weight.

 

Ya I haven't read your link yet but after searching, I found out that you need 58psi fuel pressure for the jet pump to transfer fuel, I set the pressure at 43 psi since the siemens 80lb injectors are rated at 83lb'ers at 3 bar fuel pressure and I figured that would be enough for this car....

However now my concern is, will the boost referenced regulator be able to raise pressure above 58psi when under boost or will the factory regulator not allow me to...

And now the problem with this bosch pump lol, I hate liking cars

 

If I understand correctly you've got a fuel pressure regulator on the new return line that closes at 43psi and initiates the secondary pump? Trying to determine whether your setup has artificially limited the car to a 43psi fuel system or not. I'm guessing you don't have a fuel pressure gauge installed in the car to see what is going on?

 

No, the car is supercharged so I have a normally open hobbs switch that is set to close the secondary fuel pump circuit anytime the car sees 4psi+, I cut off the schrader vavle fitting on the end of the stock rail and welded a -6 bung on and put a boost referenced regulator on with a return back to the tank...

So yes the car is set to 43 psi and the stock regulator wouldn't even be able to raise the pressure if it tried... so I read that you need 58psi in order to create enough vacuum venturi to suck the fuel out of the passenger side tank and into the driverside, which is why I ran my driverside tank dry and still had a level on the gauge

 

well now i raised the fuel pressure up to 58psi and put a new bosch 044 pump in and it works again, and i know i have the proper hobbs switch in... i made some pulls and after leaning it out alittle as it was going into the 9's, now 4800rpm to 5100 rpm the injector duty cycle goes from 60% to 125% and the A/F stayed around 11.5, so it looks like fuel pressure is dropping off with the way the duty cycle spikes...

also after 5100rpm the A/F starts to go rich until i let off at 5400rpm and the A/F was at 10.0 at that point and duty cycle was at 175%

The car is a 416 stroker with ported ls3 heads and a vortech t-trim making around 14 -15 psi

do you think its possibe that the stock pump with the bosch 044 ran parallel and its own -8 feed line (until it tees at the stock rail) is not enough i thought for sure it would be more than enough

i gotta get a fuel pressure gauge with a line so i can monitor it which making the pull but for now all i have is the one on the rail

 

also do you think that that stock regulator isn't allowing the boost referanced regulator to do its job and the raise the pressure as boost increases

 

With that huge change in duty cycle it makes sense that fuel pressure is dropping way off. You really need to be able to monitor that fuel pressure from the seat to know for sure. Between the two pumps you should have more than enough volume/pressure.

 

PM "SPINMONSTER" and ask him what he thinks...he's running an external pump and can give you better firsthand info.

 

I replaced the vacuum line to the regulator as well because it wasn't working properly, so now at this point the duty cycle is beloow 100% until 5200rpm, and then it shoots up, is a bosch 044 and stock pump in parallel not enough for approximately 750 - 800rwhp

 

is it true that you need 58psi of fuel pressure as well in order to keep the factory fuel pump bucket filled as well, because i gues i coulda damged the stock fuel pump froim all the pulls and the pump running dry up top because the bucket wasnt staying full, as well as running the tank dry

 

As stated in my PM back to you, the Bosch 044 supports around 700 on its own and it supports over 800rwtq running with the stock pump as ECS does it. The A&A kit uses a blocking valve on the stock line that keeps the stock unit from contributing and relies soley on the bosch pump.

You have 3 options:
1-replace the stock pump running the proper rail pressure
2-add a BAP to the bosch input voltage to extend it out to 900rwhp
3-replace the bosch with a A1000 that supports 750-800rwhp without the voltage control unit from Aeromotive, and 1000hp with it.

I think the replacement of the stock unit will be needed eventually and its the cheapest option. I would swap it and move on.

 

yes that was the direction i was putting my friend in as if the stock pump is hurt then it will eventually fail, cause this is his username and he read ur pm about the bosch with the bap supporting 900rwhp and he wanted t do that but i would rather see him spend the money on a new z06 pump rather than a bap since they cost around the same and then his setup should good for atleast 1000rwhp although now the rear has to come down for the 3rd time now lol..

but like i said I have good pressure at idle im just suspecting that the stock pump could have gotten hurt from running dry but i dont wanna just throw parts at it, so im gonna see if making a pull without the bosch hooked up and see what the stock pump holds uo to, or may a fuel volume test through the return line into a jug to test it... but we shall see

btw thanks everyone for the help

 

[QUOTE= The A&A kit uses a blocking valve on the stock line that keeps the stock unit from contributing and relies soley on the bosch pump.
.[/QUOTE]

oh thats why my setup is not working ?
i have the same problem, venturi pump does not move fuel from passenger tank to drivers side, so when i get close to 1/2 tank and after a long drive my fuel gauge drops to zero and i get "service fuel system " and i get these DTCs
P2066 "Fuel Level Sensor 2 Performance" EPA Pending ($11) "Engine Control Module (ECM)"
P0102 "Mass Air Flow (MAF) Sensor Circuit Low" HC ($11) "Engine Control Module (ECM)"
P2066 "Fuel Level Sensor 2 Performance" C ($11) "Engine Control Module (ECM)"
P2119 "Throttle Closed Position Performance" PHC ($11) "Engine Control Module (ECM)"
P2636 "Fuel Pump 2 Flow Insufficient" HC ($11) "Engine Control Module (ECM)"

i installed A&A kit but i did not use the one way valve to close down stock line, i installed it so it contributes with the external pump.


regards
Rune