Low pressure fuel pump psi

[Westley117]

So I recently installed the Bravo Alpha in tank fuel pump and I went from seeing 90psi-110 psi to 40psi-60psi. Is this normal? I have a 2016 FiST. Mods are Cobb old style intake, MBRP exhaust, stratified 93 tune, turbo smart plumb back. Reason I replaced it was because during high WOT the engine would misfire and reduce power. Once I let off and resume regular driving it's fine. It's very sporadic too.

 

[haste]

What kind of spark plugs and gap are you running?

 

[Westley117]

What kind of spark plugs and gap are you running?

I'm using the NGK step colder plugs and gapped at 0.026

 

[haste]

I'm using the NGK step colder plugs and gapped at 0.026

How old are the plugs and have you verified the gaps? They tend to open up with more usage and can cause misfiring.

 

[Westley117]

How old are the plugs and have you verified the gaps? They tend to open up with more usage and can cause misfiring.

It's been a while but when the issue started I checked them even switched to the motorcraft plugs to see if it changes anything, which it didn't do anything. Maybe it needs a smaller gap?

 

[dhminer]

Your LPFP pressure looked good before the swap. You monitored HPFP and sure that it's doing its thing? FRP Actual I think is the monitor. Your LPFP pressure is way low now too, maybe something wrong with the install or the pump itself. Seems like one issue now became two issues unfortunately.

 

[xxiaze]

There are two probable possibilities here, but first a question to narrow it down. As soon as you installed it, did you see that psi? Or did you install it and it was good then shortly after you saw low psi? If Its the latter then I would assume your pickup line burst and the unit needs rework. Next, if the above does not apply did you have an OEM pump and then swap in your BA pump on same tune? If so, it’s likely you need to have the voltage request adjusted by your tuner to accommodate the new pumps demand… unless the tuner is sending full voltage to the pump (not all tuners do this) it’s very likely you need some adjustment done in the ECU to get it functioning properly. I also had lowside issues.. but even at 40psi my HPFP was able to pick up the slack and function properly. Are you running aux fuel? If it’s just stock fueling it’s safe to drive but needs to be corrected, avoid WOT for the time being.

 

[ron@whoosh]

So I recently installed the Bravo Alpha in tank fuel pump and I went from seeing 90psi-110 psi to 40psi-60psi. Is this normal? I have a 2016 FiST. Mods are Cobb old style intake, MBRP exhaust, stratified 93 tune, turbo smart plumb back. Reason I replaced it was because during high WOT the engine would misfire and reduce power. Once I let off and resume regular driving it's fine. It's very sporadic too.

have you received a revised tune for the pump upgrade?
the upgrade is not just a drop in, it requires a calibration change just like ANY other fuel system upgrade (30% injectors, XDI pump, Bravo in-tank pump)

 

[Westley117]

Your LPFP pressure looked good before the swap. You monitored HPFP and sure that it's doing its thing? FRP Actual I think is the monitor. Your LPFP pressure is way low now too, maybe something wrong with the install or the pump itself. Seems like one issue now became two issues unfortunately.

I'll monitor today and send a picture of it.

 

[Westley117]

There are two probable possibilities here, but first a question to narrow it down. As soon as you installed it, did you see that psi? Or did you install it and it was good then shortly after you saw low psi? If Its the latter then I would assume your pickup line burst and the unit needs rework. Next, if the above does not apply did you have an OEM pump and then swap in your BA pump on same tune? If so, it’s likely you need to have the voltage request adjusted by your tuner to accommodate the new pumps demand… unless the tuner is sending full voltage to the pump (not all tuners do this) it’s very likely you need some adjustment done in the ECU to get it functioning properly. I also had lowside issues.. but even at 40psi my HPFP was able to pick up the slack and function properly. Are you running aux fuel? If it’s just stock fueling it’s safe to drive but needs to be corrected, avoid WOT for the time being.

As soon as I installed and started the car. It was up there in the 90psi+ then after a drive it dropped down to between 50 and 70psi. The AFR ready normal even on WOT. No lean and not super rich. Just slightly rich.

 

[Westley117]

have you received a revised tune for the pump upgrade?
the upgrade is not just a drop in, it requires a calibration change just like ANY other fuel system upgrade (30% injectors, XDI pump, Bravo in-tank pump)

I have not done a revised tune yet. I do plan on doing one. I was having some fueling issues. Sporadic hesitation at high rpm. So I began monitoring low side FP Actual, FRP Actual and FRP Desired and saw that it would dip on low side FP and followed by a dip in the FRP Actual as well. So I assumed replacing with a bigger fuel pump would help with that issue.

 

[Westley117]

This is from my drive home from work.

 

[Rocketst]

Westley, I also have a code for low fuel pressure low side after installing the bravo alpha fuel pump and I'm running a tune. The way you have to tune the pump is to trick the car by changing the voltage so you aren't sending too much fuel into the hpfp. Due to this you'll get a low side low pressure code because the voltage isn't reading correctly. If you want, a tuner can turn this code off for you. As of right now though, if your in the 12s afr at wot and don't go higher than 16 while cruising there's nothing wrong with your fuel. Do get that calibrated though as without a tune for it it will do nothing to benefit the car.

Sent from my IN2019 using Tapatalk

 

[Westley117]

Westley, I also have a code for low fuel pressure low side after installing the bravo alpha fuel pump and I'm running a tune. The way you have to tune the pump is to trick the car by changing the voltage so you aren't sending too much fuel into the hpfp. Due to this you'll get a low side low pressure code because the voltage isn't reading correctly. If you want, a tuner can turn this code off for you. As of right now though, if your in the 12s afr at wot and don't go higher than 16 while cruising there's nothing wrong with your fuel. Do get that calibrated though as without a tune for it it will do nothing to benefit the car.

Sent from my IN2019 using Tapatalk

Ahhh gotcha. So far the AFR have been normal even in WOT it's in the 11s and sometimes drop into the 10s. But I do plan on getting it calibrated. Just need to install the rest of the parts before doing a pro tune. I appreciate the help guys!!!