Hi there , thanks in advance for going over my post.

last sunday
i drove my truck , everything was going well.
and soon as i get off the freeway it dies on me.

fuel pump was not priming anymore
i turn on and off multiple time the system and finally the fuel pump started to working and i was able to get back home
but the engine was running king rough , glad i was ony a block away

the pressure was only about 45 . i probe the fuel pump and the max was 45 psi

next day after work i jump on it to do more diagnos
to find out now
when the computer prime the pump it is still 45psi
now if i probe the pump i get 60psi , i stop the pump and goes back right away to 45psi

i probe again the pump , get 60 psi , while the pump running I clamp the fuel line before the rails , turn off the pump , the pressure stay at 60psi = that tells me the bleed off does not come from my injectors

engine dont start unless i press gas pedal , and it will run bad like miss firing or something

now question

could it the pump only ? does that happen a fuel pump stop working and work again?
or a mix or fuel pressure regulator and fuel pump ?
does a corvette styl fpr can work with a pump delivery 350 LPH ?

fuel pump is a walbro inline brand new , gsl396 350lph
i have a corvettle fuel filter regulator ( i had a walbro 255 previously with same system and never had an issue , only change was this new walbro 396 )
return line back into send line ( ls swap conversion)

any ideas?
Reply

 

Which year LS, PCM and what is the fuel setup

 

I have never had an external pump and a Corvette filter/ regulator? Why did you switch from the 255 to the 350gph? When you say probe the pump so you mean provide 12V directly?

 

Some pumps have 2 speeds that they switch automatically. This could explain why you see what you see when you directly connected to voltage for testing.

 

Hard starting was from too much gas in cylinder
At that time i also swap bigger injectors in and bever rectify the tune ( cold start , accel pw ect)
I was flooding the engine

I also upgraded all the wiring size for the fuel.

It never happen again

 

Not sure what just happened!