A/F gauge reading right?
09-08-2008, 07:42 AM
#1
A/F gauge reading right? My buddy just bought a 93 Z with the LT4 H/C/I package... etc...
He has this A/F gauge in his car...
http://autometer.com/cat_gaugedetail...earch&gid=2606
Is it worth a crap.... it jumps to lein ALOT while driving around.
No it does not have a tune on it but shouldn't it be running Rich? It seems like its loading up when we we're just idleing around... Need some help with it..
Thanks
He has this A/F gauge in his car...
http://autometer.com/cat_gaugedetail...earch&gid=2606
Is it worth a crap.... it jumps to lein ALOT while driving around.
No it does not have a tune on it but shouldn't it be running Rich? It seems like its loading up when we we're just idleing around... Need some help with it..
Thanks
09-08-2008, 08:23 AM
#2
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i could be incorrect...but i THINK it reads @ WOT
mine use to jump around alot..but i only cared for wut it was reading @ WOT...i think all are like this but i could be wrong
mine use to jump around alot..but i only cared for wut it was reading @ WOT...i think all are like this but i could be wrong
09-08-2008, 10:44 AM
#4
I think that sounds like perfectly normal behavior.
Narrow band o2 sensor gauges are just a light show and wont really tell you anything. Your pcm switches between rich and lean at part throttle to keep your air fuel ratio at stoich on average which is the jumping around you see.
When you get on the gas wot style it will read rich because its in the mid 12's for a/f if its tuned properly, this will read about 900mv from the sensor or pretty much dead rich.
When you get off the gas from wot you go into dfco and the injectors shut off while the engine decelerates then kick back on and that is why you see it flash lean after a wot pull.
Narrow band o2 sensor gauges are just a light show and wont really tell you anything. Your pcm switches between rich and lean at part throttle to keep your air fuel ratio at stoich on average which is the jumping around you see.
When you get on the gas wot style it will read rich because its in the mid 12's for a/f if its tuned properly, this will read about 900mv from the sensor or pretty much dead rich.
When you get off the gas from wot you go into dfco and the injectors shut off while the engine decelerates then kick back on and that is why you see it flash lean after a wot pull.
09-08-2008, 10:46 AM
#5
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Well, according to most here, which I believe considering how it is "Those are just light shows and are worthless to read what the actual AF:R is". For best performance you'll want it a bit more rich on WOT than stock does, and during cruising for better gas mileage lean would be better (depending on HOW lean and rich it goes mind you). Best is just getting a wide band and a digital gauge that'll tell you the exact ratio.
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09-08-2008, 12:36 PM
#8
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A/F gauges mean nothing until you get a wideband gauge with a seperate O2 sensor.... Thats when they read correctly.
09-08-2008, 02:30 PM
#9
Setting a lean a/f code could just be an exhaust leak too. You need to get a datalog from a scanner like freescan or datamaster. The lean code is set when both the long and short term fuel trims reach thier maximum. This could be for any number of reasons. The easiest way to get it right the first time is to be able to see what all the engine sensors are doing while its running.
You actually can learn information about wot from a narrow band sensor on these cars. They will most certainly tell you the shape of your a/f curve at wot. Most I have tuned end up in the 890-905mv range, but your gauge does not give you access to that info and things happen much to fast even if it did.
Also if you tune one of these cars for wot. Best results will be at the track. When tuned for max power on the dyno I find that they are always lean down the racetrack. I usually just take cars down to the local 1/8 mile with wideband in tow to fix up the wot fueling and timing.
You actually can learn information about wot from a narrow band sensor on these cars. They will most certainly tell you the shape of your a/f curve at wot. Most I have tuned end up in the 890-905mv range, but your gauge does not give you access to that info and things happen much to fast even if it did.
Also if you tune one of these cars for wot. Best results will be at the track. When tuned for max power on the dyno I find that they are always lean down the racetrack. I usually just take cars down to the local 1/8 mile with wideband in tow to fix up the wot fueling and timing.
09-09-2008, 02:09 PM
#12
Ok, so the guy we got the car from gave us 30lbs injectors...
We installed them and it runs 80% better... still feel a bit of a "miss" but alot better...
Anything else we should check, we plan on doin plugs too so that might clear it up...
We installed them and it runs 80% better... still feel a bit of a "miss" but alot better...
Anything else we should check, we plan on doin plugs too so that might clear it up...
