or at least mine
anyway, I just thought I'd share what I had, and what I replaced, and how everything went:
I was feeling the following problems:
-Hesitation at partial throttle as I accelerated through 3K-4K RPM.
-lack of WOT performance above 5K-6K RPM.
-lack of smooth accleration in the low cam at WOT
and what my A/F gauge was telling me wasn't good (its a digital volt meter... not LED's) most H22's O2 sensor's show around .80v-.83v at WOT in VTEC. higher voltage is richer, lower is leaner) mine was showing as low as .55v at high RPM.
- when the hesitation reared its ugly head at low RPM, the A/f gauge would dive to the lean side
- on the top end, the A/F gauge would approach 0.55v. that is way to lean.
because of this, I suspected a fuel problem... so:
I replaced the fuel filter and fuel pump. and nothing changed.
THEN I replaced the ignition coil, plugs, wires, cap, and rotor. the best way to describe the before / after results are in the graph I made below:
the red line indicates how good the car felt (accleration) and the blue line reperesnts what my A/F gauge was showing me the center gray line indicates a 'normal' acceleration, and a 'stoich' mixture. as you know, the car should run well above (richer) then that.
anyway, hope that makes sense. as you can see, replacing the ignition components REDUCED the hesitation at low RPM, and smoothed out the A/F ratio. The reason for this, is that the old (120,000 miles) igntion system was having a hard time cutting through all the air and fuel, and consequently was misfiring. At first, i was terrorfied that I was running lean and was going to blow something up, but a friend tipped me off when he said that when I accelerated away in VTEC, there was black smoke pouring out the back. This pointed out to me that not only was too much air going through the exhaust, too much fuel was too. This was underlined by the sounds of popping exhausts in my clogged cat.
However, while this REDUCED the hesitation, it didn't get rid of it. I still felt a little hickup in the powerband at partial throttle, and when I felt it, my AF gauge would jump down to as low as ..40v... which is WAY lean. Again, I suspected a misfiring problem rather then fuel problem, so I started thinking 'bout it:
the H22 has an ingition timing advance that you can feel kick just a bit around 3K. around 4K RPM, it also switches between open and closed loop.... at some point in this area, at partial throttle, you have the ignition advancing and the mixture turning to the rich side at this point (just before it the ECU switches between open & closed loop). With a pantload of fuel going into a high-then-normal compression motor, and plugs gapped to the USDM spec (.044), I think the spark has dificulty jumping through everything to start combustion... so I did this:
IF YOU HAVE A V-AFC
first, adjust the low throttle range to below 50% (around 45 is fine) so that these settings do not affect higher throttle situations (when running rich is a must)
starting at about -2% at idle, slope the fuel curve down to about -9% at 3,200 RPM. peak at the bottm at about 3700 rpm at -10%, then slope it back up to -5% just before vtec engagement. THIS IS OK. you can run lean at low throttle, low rpm situations and not hurt anything.
Anyway, that fixed it for me!!!!
if you don't have a VAFC, or that doesn't get rid of the problem, do one of the two following things:
#1- buy an MSD blaster coil and cap.
#2 - gap your plugs slightly smaller.
that did it for me, just thought I'd share. car runs good again!
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