Engine Limited before 4000rpms

[Paul_M]

Hi guys

After months of working on my VE board smoothing it out with LTFT, I got my wideband and upgraded my injectors so I could go WOT.

So I decided to hit some cells and I begin to feel how my engine is limited and there are jerks, these happen when reaching 4000 rpm, my wideband went up to 22 afr, the injectors are new, tested in the laboratory, it will be a fuel pump insufficient fuel? My idle fuel pressure is 55 psi, no DTC for now, thanks for your help

Silverado 2003 RCSB
5.3 bored to 5.7 with 243 heads
230/242 113 .625/.605 camshaft.
.660 btr valve springs
12613412 injectors
long tube headers no cats.

SD_04_06_23.hpt
Only4000rpms.hpl

[SiriusC1024]

You're getting KR and actual lambda isn't even close to commanded.

[Paul_M]

You're getting KR and actual lambda isn't even close to commanded.

so i have a bad wideband sensor?

[5FDP]

Seems like you're running out of fuel. At 3,400rpm the o2 sensors take a nose dive and it starts to lean out.

You need to check the pressure while it's under load, 55psi at idle means nothing if it can't keep up with higher fuel demand.

[Josue Galban]

Hi guys

After months of working on my VE board smoothing it out with LTFT, I got my wideband and upgraded my injectors so I could go WOT.

So I decided to hit some cells and I begin to feel how my engine is limited and there are jerks, these happen when reaching 4000 rpm, my wideband went up to 22 afr, the injectors are new, tested in the laboratory, it will be a fuel pump insufficient fuel? My idle fuel pressure is 55 psi, no DTC for now, thanks for your help

Silverado 2003 RCSB
5.3 bored to 5.7 with 243 heads
230/242 113 .625/.605 camshaft.
.660 btr valve springs
12613412 injectors
long tube headers no cats.

SD_04_06_23.hpt
Only4000rpms.hpl

check the fuel pressure of your fuel pump

[Paul_M]

I will get the pressure gauge and I will return here to inform you, thanks for your answers

[Josue Galban]

I will get the pressure gauge and I will return here to inform you, thanks for your answers

perfect

[Paul_M]

Seems like you're running out of fuel. At 3,400rpm the o2 sensors take a nose dive and it starts to lean out.

You need to check the pressure while it's under load, 55psi at idle means nothing if it can't keep up with higher fuel demand.

I already checked my fuel pressure:

idle: 55psi
Moderate speed: 50psi
WOT: 25psi

I think it's time to update my fuel pump, which do you recommend?

Running rail system with vacuum regulator on them

[5FDP]

If not going forced induction, a 255 LPH pump would be fine.

[SiriusC1024]

Are you sure that the fuel filter isn't clogged?

If not then get an entire sending unit. Walbro, Racetronix, Aeromotive...all good products.

[Paul_M]

If not going forced induction, a 255 LPH pump would be fine.

255lph can hold a 100 nos wet shot with external fuel cell?

[Paul_M]

Are you sure that the fuel filter isn't clogged?

If not then get an entire sending unit. Walbro, Racetronix, Aeromotive...all good products.

It is too much gasoline pressure that drops to be a clogged fuel filter, but i will chage it

[TheMechanic]

It is too much gasoline pressure that drops to be a clogged fuel filter, but i will chage it

Just pull it off and blow through it with your mouth. Take my word for it. You will know if it is restricted or plugged.

[SiriusC1024]

Mmmm tingly lips. Don't forget hum in it like a kazoo.

[Paul_M]

Just pull it off and blow through it with your mouth. Take my word for it. You will know if it is restricted or plugged.

i did change my fuel filter, it was clogged, i did check my fuel pressure again:

idle: 58 psi
moderate speed: 55 psi
WOT: 30psi

i will go with a walbro 255 i just want it can hold a 100 hp wet shot

[Paul_M]

Mmmm tingly lips. Don't forget hum in it like a kazoo.

bad experiences in back times lol

[Paul_M]

okay guys im back, yesterday i did install my new walbro 255, running with 1/4 gas in the tank, i did ajust my VE table, and still my fuel pressure drops, some ideas? no DTCS

Walbro_Gas Station.hpl