stRodda

my engine is still running a little lean, but way too much so in vtec. i have a new fuel pump and regulator, and even after tuning, its still too lean. could it be anything else, or do i just need bigger injectors?

satan_srv

how do you know it's lean.

satan_srv

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stRodda &raquo;</TD></TR><TR><TD CLASS="quote">cause they put it on a dynojet and it showed so.</TD></TR></TABLE>

So you added fuel and it made no difference to the A/F readings? Like you have a wideband o2 readout you could post?

stRodda

they adjusted the vafc as necessary and turned up the regulator, so instead of the afr bar being totally in the red, it went to yellow. but when vtec hit, it went into the red again. i dont know much though, thats why i wanna know if i do need injectors like they told me. and ill be honest, i have no idea what the wideband o2 reading is or how they get it. that i saw, they had something hooked into the exhaust, and clamps on the sparkplug wires, but that was all i noticed. ive never used a dyno before, so i didnt know what was going on.

unfortunetly i didnt ask for them to get a print out. i didnt really care at the time. i was just all bummed out that i had to go back and get new injectors.

sharkcohen

List your mods, we'll be able to tell you if you need larger injectors.

stRodda

3" cai
dc header
hollowed cat
apex ws
crower 2 cams
springs/retainers
skunk camgears
vafc
new fuel pump & regulator(forget which ones)


btw, what size are the stock injectors on a 93jdm?

they told me i should get 370cc.

satan_srv

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stRodda &raquo;</TD></TR><TR><TD CLASS="quote">they adjusted the vafc as necessary and turned up the regulator, so instead of the afr bar being totally in the red, it went to yellow. but when vtec hit, it went into the red again. i dont know much though, thats why i wanna know if i do need injectors like they told me. and ill be honest, i have no idea what the wideband o2 reading is or how they get it. that i saw, they had something hooked into the exhaust, and clamps on the sparkplug wires, but that was all i noticed. ive never used a dyno before, so i didnt know what was going on.

unfortunetly i didnt ask for them to get a print out. i didnt really care at the time. i was just all bummed out that i had to go back and get new injectors.</TD></TR></TABLE>

That's retarded. I really doubt you couldn't adjust the V-AFC to take care of this problem. If your engine is NA there is NO WAY a V-AFC and fpr can't cover this.

If you adjusted the V-AFC "as necessary" your AFR shoudl be correct. The fact that their a/f readout is Red yellow and green makes me think it's not a wideband as it gives numbers 13.1, 14.5, 13. etc. all the way across the rpms so you can see exactly what's going on and make rpm range adjustments on the V-AFC.

pfft bigger injectors.

satan_srv

Here is a sample of my a/f reading from my dyno run. See how easy it is to know where to adjust?

stRodda

thats kinda what i figured, but they told me different, and im not one to argue. they put my car together so i assume they know what their doing. that color bar was just during the run. after the hp/tq graph shows as well as the a/f graph. i wasnt paying close attention, but they knew it went lean in vtec, so im assuming they tried to compensate for it with the controller. from what i understand, by what i was told, they increased the fuel as necessary. but the injectors just werent delivering it fast enough.

stRodda

is there a constant optimum ratio? or does it change throughout?

satan_srv

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stRodda &raquo;</TD></TR><TR><TD CLASS="quote">is there a constant optimum ratio? or does it change throughout?</TD></TR></TABLE>

As long as you have an accurate readout I don't see whay you shouldn't target 13.7:1 at wide open. The thing a V-AFC only has 8 adjustment points per cam and interpolates inbetween so you can't get a flat curve everywhere. And also engine dynamics come into play, as you adjust you may find that going leaner doesn't help so it's pointless.

I have 370cc injectors on my motor but I can't imagine I'm running anywhere near that high of duty cycle.

JDM injectors are 330-345cc I really have a tough time believe it's the injectors as many people run Crower stage2 cams on 5th gen 290cc injectors without problems. Whoever tuned your -V-AFC sucks, what are your settings?

stRodda

im hoping its not the fault of the tuners, i trust their work. they did a great job on the install. ill find out for sure what the deal is when they swap in another set of prelude injectors tomorrow. ive never really used the vafc, i just got it for them to tune with. what settings were you wondering about, and i will look through it. for one i know, they set the vtec way up to 6500. basically to turn it off until the fuel problem is fixed.

it was getting better. when they did the first run before changing the regulator it made only 120whp. after the regulator it got to 180.1

what could affect the a/f readout? would it help to get a new o2 sensor?

satan_srv

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stRodda &raquo;</TD></TR><TR><TD CLASS="quote">im hoping its not the fault of the tuners, i trust their work. they did a great job on the install. ill find out for sure what the deal is when they swap in another set of prelude injectors tomorrow. ive never really used the vafc, i just got it for them to tune with. what settings were you wondering about, and i will look through it. for one i know, they set the vtec way up to 6500. basically to turn it off until the fuel problem is fixed.

it was getting better. when they did the first run before changing the regulator it made only 120whp. after the regulator it got to 180.1

what could affect the a/f readout? would it help to get a new o2 sensor?</TD></TR></TABLE>

no the wideband sensor is the thing they stick in your tailpipe. The stock o2 sensor is not accurate like that.

i think if you have 120whp to start with you have a lot more problems then tuning, what was your fuel presure?

aeolus

would you mind mentioning who the tuner is???

stRodda

oh ok, they did have a wideband sensor then. and the pressure was low. the 120 was before they put on the new regulator. but it was one without a gauge, so i dont know what the pressure was set at. sorry for not giving much info, i know its making it harder to help, but ill find out more tomm and hopefully everything should be better. or at least i should know for sure what the problem is.

stRodda

id prefer not to yet. i want to give them another chance first before i start ruining reps. maybe it is just a dirty or faulty injector. we'll see. ill post an update after i get back saturday.

satan_srv

check the fp, maybe it's way too low. stock is 38-42psi

stRodda

how is that done? is a gauge hooked up to the hose going into the regulator? should the pressure stay stock, or should it be higher because of the mods?

sharkcohen

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by satan_srv &raquo;</TD></TR><TR><TD CLASS="quote">check the fp, maybe it's way too low. stock is 38-42psi</TD></TR></TABLE>
^^^That's what I just popped in to mention myself. You definitely do not need larger injectors.

As for the colored bar graph you were seeing, that's the real time readout that displays in the dyno software during the run. After the run, when the graph displays there should be an option somewhere to bring the a/f curve up along with the torque and power curves.

sharkcohen

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stRodda &raquo;</TD></TR><TR><TD CLASS="quote">should the pressure stay stock, or should it be higher because of the mods?</TD></TR></TABLE>
You will probably find that your pressure should be set in the higher end of the stock range. Then you will use the vafc to take fuel back out where it is needed.

satan_srv

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sharkcohen &raquo;</TD></TR><TR><TD CLASS="quote">
You will probably find that your pressure should be set in the higher end of the stock range. Then you will use the vafc to take fuel back out where it is needed.</TD></TR></TABLE>

I agree at least get to 42 or so, I mean you probably have no tuning to do for the low cam, so keeping a stock fp ensures you won't run too rich down low, saves you v-afc tuning.

Yes you can attach a guage to the fuel line right where it goes to the rail.