Lei Siew Long

ok, i've been told two seperate things. one, is that the autometer a/f gauge doesn't work in an open loop. from what the person said "it doesn't work under WOT." while someone else told me to let the turbo spool to max boost at third and fourth to see what the a/f gauges shows. he said under WOT under those gears mainly are where the most accurate or close to accurate readings are at. and he said since it is open loop, it only works under WOT.

i'm asking this because i tried what the second person told me, punched it in third, turbo spooling, and when i reach 7k, it jumps all the way down to lean...should i worry?

secondly, what gauge is the most accurate or close to being accurate for avoiding detonation? another brand of a/f gauge, egt gauge, or signs of detonation. thanks in adv

Ubermensch

This is my understanding, someone correct me if I'm wrong.

1) The stock O2 sensor is only accurate very close to stoich (14.7). You'll know when your rich or lean by a good margin, but you won't tell the difference between 14.5 and 14.7

2)During open loop operation (WOT) the ECU is running directly from the fuel map and therefore not reading the O2 sensor, or at least not making adjustments based on its reading.

3)During closed loop operation the ECU is checking the O2 reading and constantly making small adjustments to maximize fuel efficiency.

I'm not sure if Zip reads this board, but he has a lot of experience with this stuff so he could probably give you a better answer. Of course there are plenty of other knowledgable people on this board so I'm sure one of them will confirm or refute my statements.

00 Si

Just to add my two cents, I had one on my Eclipse GS-T. I also had an Apexi S-AFC to tune the car. Together they worked great. When the AFC was running kinda lean, it showed it on the A/F guage perfectly even at WOT.

VaporTrail

It's as accurate as can be had while reading off the factory sensor. The thing is, the autometer or any other gauge like it can only read what the ECU reads. Typically, because the range is so narrow, this is either rich, lean, or stoich. If you REALLY wanna know, visit a dynojet which has a wideband o2 - it'll be some of the most useful information you will find, bar none. It can not only tell you if you are lean, rich or stoich, but HOW lean exactly, with a numberical value, and a graphed out plot of a/f vs rpm. You can see exactly how rich, or how lean, at any rpm.

b18bturbo

isnt that the truth. Its limited to what the o2 sensor can seee. The o2 sensor and most guages are based on .1v increments. If you can .01 or tinier out of the o2 then you could really tune off a guage.

paulzy

iTrader: (1)

get a motec a/f metering kit. If you don't have the funds, then a tomei is the closest...

if you do get the motec, I suggest you get one of their exhaust systems too haha


[Modified by Slow_ass_4dr, 2:15 PM 7/3/2001]