JustBlaze Posted November 10, 2022 Report Share Posted November 10, 2022 been experiencing Fuel pressure drop at wot which looks like it starts dropping around 5500rpm. looking at my log, I can see a dip in the batt volt around when the issue seems to be happening. can anyone here have a quick look at my screenshot and confirm this issue is related to my differential fuel pressure drop? Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 10, 2022 Report Share Posted November 10, 2022 The voltage measured at the ecu unlikely has much resemblence of what the voltage is at the pump, you really need to measure voltage at the pump it that is your concern. Your pressure drops with increasing duty cycle so it is obviously a lack of fuel flow, but that may or may not be caused by pump voltage. JustBlaze 1 Quote Link to comment Share on other sites More sharing options...
Pete_89t2 Posted November 10, 2022 Report Share Posted November 10, 2022 Given the kind of boost you've got in that log screenshot, I'd assume you have a very robust aftermarket fuel pump in there that is pulling a lot more current than the OEM pump did. So my first question would be how do you have the fuel pump wired - was the wiring upgraded to handle the additional current draw of the new pump? If there are any tank bulkhead connectors in the fuel pump circuit/wiring, first thing I'd do is take a close look at them and any other connection points in your fuel pump circuit - look for signs of melting and/or burned contact terminals. If you see any of that, you'll need to upgrade the wiring on your fuel pump circuit. If not, take voltage measurements at the pump while doing another pull as Adam suggested to rule out voltage drops as the root cause. If pump voltage is good, next thing I'd look into is the fuel pressure regulator. JustBlaze 1 Quote Link to comment Share on other sites More sharing options...
JustBlaze Posted November 26, 2022 Author Report Share Posted November 26, 2022 hmmm not sure why I wasn't notified about these responses, But thanks for getting back to me guys. to answer your question Pete. i am running a Walbro 255 lift pump, with staged dual walbro 460 surge tank setup. wiring was upgraded to handle this fuel system. The FPR is a Brand new Turbosmart fpr1200. after you mentioned melting, i did notice a little bit of melt at the alternator terminal which i thought may have been caused by the dump pipe being too close to the Alt but i might inspect that further. As you both mentioned it looks as though i'll have to find some way of measuring voltage at the pumps under load. didn't experience this issue on pump fuel at 22psi boost, only when we dialled in e85 on flex fuel and up the boost this issue appeared Quote Link to comment Share on other sites More sharing options...
remski2 Posted November 27, 2022 Report Share Posted November 27, 2022 Could it be that your staged stetup (2nd pump coming on) is causing the issuess ? Do you run staged when on pump gas? Being how is your staged setup activated.. Quote Link to comment Share on other sites More sharing options...
JustBlaze Posted November 27, 2022 Author Report Share Posted November 27, 2022 yes I do run staged on pump fuel as well, second pump activates at 11psi setup through aux output. pump gas holds fuel pressure no worries. i know e85 requires more fuel meaning higher demand on the pumps. so im thinking either one of my pumps is cactus or i'm dropping volt at pumps linked to possible alternator problem Quote Link to comment Share on other sites More sharing options...
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