Fuel Pressure

[dec010974]

you got the general idea.

[BR3W CITY]

Originally Posted by dec010974

sorry, I forgot to up load the pics. also does anyone know the specs of a walbro 255, inline fuel pump? t

255 liters per hour at up to ~90psi. 12v feed, 10mm inlet and outlet threading.

[dec010974]

thanks br3w City. That means the Walbro 255 fuel pump, should flow enough fuel for any ls1 swap, up to a 58 PSI, WOT. In a 12 volt system, what would alter the Walbro's Performance, to a measly 48 PSI and lower? I guess I will never know. Oh yeah ls1nova71, when I removed the vacuum line, from the Fuel Pressure Regulator, it rose between to 53 and 54 PSI.

[BR3W CITY]

Originally Posted by dec010974

thanks br3w City. That means the Walbro 255 fuel pump, should flow enough fuel for any ls1 swap, up to a 58 PSI, WOT. In a 12 volt system, what would alter the Walbro's Performance, to a measly 48 PSI and lower? I guess I will never know. Oh yeah ls1nova71, when I removed the vacuum line, from the Fuel Pressure Regulator, it rose between to 53 and 54 PSI.

The pump doesn't know what pressure its running, it just does it. At like 12.5v, its the 90psi or whatever its rated to...but because of electrical load, it may not actually get that full voltage at all time. Some people run a boostapump which over-volts or holds constant the fuel pump @ 12.5-14v which increases its output. Others (like me) just "hotwire" the fuel pump to run a direct switched voltage, so the pump gets its "regular" voltage, and don't tie other power-drawing devices onto the same circuit.

The fuel pressure regulator will lower the input line pressure to the desired pressure based on the vacuum reference. If you were to run boost, it would actually attempt to slightly increase pressure.

[dec010974]

good news fellas. the eagle has finally landed. fuel pressure is back on track. im assuming it was a regulator problem. Thanks again to all my friends that chimed in. Brew City, ls1nova71, dayj1, & clinebarger. all that's left now is to call the smart guy up for a retune, adjust the th400 shift points and boom, we'll have magic. deuces.

[Cuate]

Can I just plug the return line on the truck style intake with the regulator? I'm using the corvette style regulator/ filter.
Posted via Mobile Device

[mooseknuckles]

Originally Posted by dec010974

I can drive this truck anywhere, but when I stomp the throttle, it bogs, badly, stumbles until I ease off the throttle, let the fuel build up and stomp the throttle again. when driving the truck, I have to ease into the throttle to get it moving. at this time, smoky burnouts leads to dead throttle until I ease off a bit and gradually increase the throttle. any help is appreciated.

sounds like the exact same problem I'm having with my 5.3/700r4, but I've had the vette filter/walbro pump set up right from the start, switched pumps, filters, regulator, checked fuel pressure...I never did get it figured out...

[dec010974]

Hello. Sorry for late reply. We all need help sometimes. Since I made the changes, the engine runs goo with no problems. Cuaute, don't quote me but I would run a single line fuel rail with the corvette fuel filter regulator. GM intended for it to run that way. I have one if you need it.
mooseknucles, hit me up via pm. Give your number, and I'll give you a call. I would start with the filter before the pump. These swaps get easier and easier every time I do them. You will get it right. I can do a harness with my eyes closed. Happy new year.

[Cuate]

I attached a picture of the fuel rail I have now.

[dec010974]

Cuate I used a stock fuel rail like this one. there is no regulator. you will use a corvette fuel filter regulator. the two, paired, will be a match made in heaven. they have a few fuel rails, for sale, on ebay.