Alright, i have a d16z6 and i'm having big problems with my fuel curves. I have an apexi vafc2 as a fuel controller(I know, it's a pain in the ***) and rc 440cc injectors, and a walbro 255lph fuel pump. I'm getting 40lbs of pressure to the fuel rail. Ever since i've installed my vafc, my motor has wanted to run very rich although I keep the curve at zero w/ no changes to stock. It's really pissing me off, because I can't get my motor to run stoich on my autometer a/f gauge like before I installed the vafc, but i can adjust it to seemingly run stoich. Why would installing the vafc cause my motor to run rich w/out adjustment, what other causes could i look out for? Would running rich cause my new bosch o2 sensor to clog up and give faulty voltage readings? My main problem is my a/f gauge not moving anymore and I don't know how it's running. Any advice would be very helpful. Thanks guys.

 

to get good results on the vacf2 it would need to be done with a wideband and dyno, not that autometer gauge

 

that's what i was thinking also, but i still can't figure out why my car is running rich. Who makes a good wideband system. Is aem's uego any good comparable to a motec system. I want to invest in my own wideband, but can't decide on such an important (and expensive) investment. Thanks, though

 

It is quite common to see higher fuel pressure after installing a Walbro 255 using a stock FPR. Do you know what your fuel pressure was before installing the pump?

If you've got the VAFC zeroed out, the MAP output should mimic the MAP input, which would leave a possible increase in fuel pressure to explain your richness. I say possible, because 40psi, I think, is within stock limits...so....

The Bosch O2 could also cause you to run rich. The Bosch O2's don't typically switch as fast as OEM O2's and this leads to running rich - its a side effect of a slow O2 (good for racing, not good for fuel economy). And yes, running rich can foul out an O2 sensor and cause faulty readings.

 

i've never tuned an AFC before but shouldn't you need to turn down the fuel on the AFC since you are running larger than stock injectors?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CivicMike &raquo;</TD></TR><TR><TD CLASS="quote">i've never tuned an AFC before but shouldn't you need to turn down the fuel on the AFC since you are running larger than stock injectors?</TD></TR></TABLE>

yea. just realized you're running 440cc injectors.

thats a lot of fuel!

you should considering adjusting the map output to -35 to -40 across the board.

is this a turbo dseries??

 

no, it's a nitrous motor, but that's exactly how much i have to turn the vafc down is to -38 or so to get it to seemingly run right. It's not the 440's causing it to run rich(completely), because w/ stock injectors it runs rich also, though not as much. And at 7000 rpm w/ the rc's, it still runs way rich and i'm pulling a good duty cycle (60% or so), so they're not necessarily too big, and they idle fine. The stock fuel pressure is designed to be 43.5psi, and that's about what i'm getting. I thinking it's running rich because the rc440's require a shorter open/close signal cycle than a stock injector and the ecm isn't making up for it? The main problem is that i don't want to have to crank the fuel curve down on the vafc if the problem lies w/ something else. Any more ideas would be great and thanks for the feeback so far

 

what kind of injectors are they saturated or peak and hold? if you pulled them off a DSM you need a resistor box to run them right.