cypress_33415

Just fired up my car and found low fuel pressure. I'm running the walbro 255 intank fuel pump with the vette fuel filter with return. Any sugestions on what to check to why the pressure is so low? Don't really want to start replacing new parts with new parts.
Thanks

TomM

iTrader: (56)

Lotsa variables, how big of a fuel line, regulated or not, return line/supply line hooked up correctly, how do you know it's low, gauge..where, what does it read? More info required to begin a suggested fix.....

T,

Old Geezer

iTrader: (3)

An intank leak??
How is the pump plumbed to the sender?

cypress_33415

I'm running a 3/8 fuel line To the rail with 3/8 into the fuel filter ( wix 33737) 5/16 for the return. It is regulated through the filter. I have 25 psi at the rail (shrader valve). The pump to sending unit is plumbed with 3/8 w hose clamps. I checked voltage this morning and I'm right around 12. I was thinking of bypassing the fuel filter to see what I get? Fuel pressure good then the filter pressure bad then the pump, or intank leak??

CODE4LS1

iTrader: (4)

I would pull the pump assy. out of the tank and check the pressure hose off the pump. If it's the factory plastic flex hose they like to split causing low pressure.

three05s10

what kind of car? i had the same issue with my 89 vette swap, i just plugged the return, and i had awesome pressure= needed new filter/regulator.

bozzhawg

Try swapping the fuel filter first....... I swapped mine right before i went to the dyno, and clear gas came out at first then some brown **** cam out...... So all the sediment at the bottom of the tank must gotten trapped in the filter, plus I put some Techron in the tank when I filled up...... I changed the fuel filter and no problems.....

cypress_33415

I have an 86 ss monte carlo. In the morning I'll try blocking off the return. Hope this works. If not I guess I'll be stoping the tank. I'm itching to get this running.

three05s10

yea, if it is accessible, block the return, and have somebody watch the FP gauge, while you fire it up. if your getting the 58-60ish you need, you got a bad regulator just like me. i wouldnt run the car long like that, as youll keep building fuel psi(70+) and id hate to see a line burst or something.

cypress_33415

Geezer hit the nail on he head!!! I must be rushing getting to the end of this swap? I pulled the pump and the fuel line just about fell off the sending unit. I tightened up the hose clamps and boom, 60 psi. The car is running much better, still have some hesitation with throttle repsonse. I amagine the computer has some learning to do? Plumb the air cleaner and melt in the exhaust and I should be driving this weekend? Hopefully.