vha27

so i did the vafc hack and im still running real rich, im as low as -45 and getting too low map input cells, cell 13

so here the thing im def running way too rich, now i got the walbro pump and the dsm 450's, so i figure get an aem adjustable fpr and turn it down

now heres the question
to do the vafc hack correctly its recommened u use the bigger injectors and pump, my fuel pressure as of now, vacuum unhooked is 48 psi, stock injectors and stock pump the reading accorind to helms is 38 to i think 44

so fuel pressure increased with the pump, now im wondering did i need the bigger fuel pump in the first place since i need a lower fuel pressure, my psi would be what the factory said with bigger injectors, im so confused, all i know is that im real rich, ne advice on how much i should turn down my fuel pressure since i cant lean it out enough with my vafc? oh apexi turbo on a y8

thanks,
chris

DefiantGSR

lose the pump. Its making you run rich.

vha27

why even put 450cc's on then, if fuel pressure is the same as stcok, wont i get the same amount of fuel in?

Tony Starks

No, you be fine. Like he said. Ditch the pump. Or of course you can buy a FPR. I run the same hack set up and I used my adjustable FPR to drop the pressure. I STILL run rich.

gtcali

I've been debating if I'm going to put my inline fuel pump in. Is it recommended to not run a fuel pump with a VAFC??

MikeMAN

even though the fuel pressure is the same, the injectors will flow more..

mike

home_made_turbo

I just put the hack on my 2000si and i had the same problem. What i did to fix it was get a AEM FPR and lower the pressure at idle to 29PSI (with the vacuum line connected & with a Walbro 255). In order to get this low of a fuel pressure you need to use the gold insert that comes with the AEM FPR. Therefore at 0 vacuum I am at 39PSI with a 1:1 rise rate per pound of boost (45PSI at 6lbs of boost). With my 1000RPM set to -37 it idles just like stock, however I did have one instance where it was hard to start. Other than that I have not dynoed it yet but I am planning to next week. Also I took 2 degrees of timing out at the distributor which may have made a difference.