Hi guy's need some help here, I tried the boys in the fuel forum but did not get the info I am looking for , so I thought hey lets try the forced induction boys they must have some ideas. so here we go. The last mods on my 97 7.5 f250 have maxed out my in tank fuel pumps, (latest mods: performance cam shaft, roller rockers and bbk twin 61 mm throttle body) I'm trying to find 255 lph in tank fuel pumps that fit my stock set up. None of the performance mustang pump are the same legnth, tried a in line pump but it caused the check valves in the fuel tanks to rattle, and seemed to return fuel to both tanks. any help would be greatly appreciated.

 

Same lengths............meaning what? the pickup lines? I can't see why just about anything couldn't be custom fitted/TIG welded to make it work. Any thoughts?

 

Do you have single or dual tanks? One of the Lightning guys has a truck setup to operate both tanks at the same time. Failing that I think you're looking at some custom work on the fuel sending unit to fit a mustang pump or maybe a complete late model lightning fuel sending unit.

 

The fuel pump is located in a plastic capsual that acts like a reservoir, The top half or lid snaps onto the bottom cup wich holds the fuel pump securely. There is a 1/4 inch gap at the bottom for the pick up screen.
Do any mustangs have a similar set up ? I could try adapting the whole reservoir and pump assembly.
As for the switching valve for the dual tanks I could use somthing from a late 80's f-250 but that would add more wiring, a switching valve, an inline pump and a bunch of plumbing, (more things to go wrong on the road when I'm towing), Plus my pumps are 11 years old and should be changed anyways before they leave me on the side of the road.
Hope that all makes sense if not le me know.
Thank's

 

Yes.. I have been in there myself....



The only high volume pump I found that would fit inside the resovoir was a Carter 155L, but it didn't last long.. maybe only a year. I bought several other popular mustang pumps and they are all too long to fit inside. For whatever reason the Mustangs don't have a resovoir around the pump, it's just strapped to the hard line assembly. This may be another thing to try.



Here's the Lightning asembly with dual pumps..

 

Have you considered getting a KB boost a pump? It can be adjusted to up the voltage on the current pump, yielding much more flow from the same pump. You'll need to data log before, during and after, along with tuning, to get it dialed in properly but you can easily achieve up to about 50% more flow from the same pump.

 

personnaly I'd just connect 2 pumps in parallel almost doubling your ouput flow and saving $$, remeber guys pumps make flow, resistance to that flow makes preasure

 

I checked out the boost a pump system. I guess thats 1 option, parallel pumps ? its a long haul vehicle and keeping it reliable is my main concern, (not sure how that would work with dual tanks, keeping track of the fuel in the tanks?). The other option I thought of was increasing injector size, more volume less pressure required. But being a map sensor based system could it adapt to a slightly larger injector size?. Any experiance in this field would be appreciated.

 

No, not without a chip to tell the computer the new injector size, or a swap to MAF and the use of a "scaled" injector/meter combo.

 

What does your fuel pressure do when it goes lean? Are you monitoring your A/F ratios with a wideband?

 

At first I thought it was a fuel control issue, at around 4000 rpm wide open throttle climbing a steep grade towing my 10,000lb toy hauler, I could feel it holding back. My o2 reading would pin at 900mv (and somtimes would even shift in to closed loop after 2 min.) injector pulse would hit 18-19 ms. fuel pressure was set 35lbs koer/50lbs koer no vacuum, Next trip I mounted a external fuel guage and sure enough fuel pressure started at 50psi at wot but slowly dropped off to 40psi after a 30 seconds or so, Tried switching fuel tanks no change. Got home from that trip replaced the rear fuel pump with a oe pump ran the test again next camping trip, same results. I have checked all the fuel lines for kinks or restrictions no fault found.
The one odd thing that happened the last trip climing a steep grade, wot 4000rpm half way up the hill I got a short burst of power (unfortunatly I did not have my external guage that trip) but I asume fuel pressure spiked for 10 seconds
Thats the readers digest version I could go in to more detail if required.

 

You could try using an adjustable fuel pressure regulator to compensate for the lack of fuel at higher RPM's.

 

I have a bbk adjustable regulator with a guage mounted to it, cranked it up to 60 psi fuel pressure still falls off. You wouldn't think the fuel pump could be maxed out, but that the only conclusion I came up with.

 

What I did when I built a stout 351W for my bronco with 30 lb/hr injectors, was to use a Vortech T-Rex universal pump in between my stock pump and the injector rail. I never had a fuel pressure delivery problem.

 

I tried that route last summer, installed a walbro high pressure fuel pump after my in tank pumps, but with the dual tanks, both pumps started buzzing and fuel got returned to the wrong tank.
O.K here is my solution I run a micro switch off the throttle body that gets triggered at wot, the micro switch grounds out a relay with 2 power output pins, connect the two output wires to the tank selector switch (3 terminal switch that puts power to selected fuel pump) 1 wire to each fuel pump feed.
At wot throttle both pumps get activated regardless on which one is selected, double the volume of fuel when needed, let me know if you find any holes in this theory.
(the only draw back I can think of is having to keep a minimum amount of fuel in the tanks at all times if I want the xtra volume)