Confuzed1

iTrader: (4)

I bought an Autometer A/F and oil pressure gauge for my duel a pillar pod, but I just don't see any good use for it.

The thing bounces all over the scale 90% of the time! Could it be because I'm still running the CCC Q-jet, and since the M/C solinoid is constantly adjusting at idle/part throttle I get irratic readings?

The gauge will read slightly on the rich side, but only momentarily while I have my foot in it. Soon as I go back to idle/part throttle - I bounce all over the scale again...is this normal??

Seems the only thing it's good for is telling me whether the thing is pig rich, or way too lean. No way I could use it to adjust A/F at idle - it's too jumpy...

92 zzz28

I don't think they are very useful either. I know a guy that has one in his 90 'bird, TPI, and it does about the same thing. At idle though his is always showing a rich condition. At cruise it fluctuates back and forth across the range...

I think they are more for the looks than anything else...

Sorry to not be more helpful...

Nixon1

Don't know whether that's exactly normal or not, but you're NOT going to get very accurate readings with the A/F gauge. The reason is that the O2 sensor normal cars run is not a wide-band O2 sensor. Meaning, it's a sloppy and inaccurate reading...it's basically meant to read 3 conditions: lean, stoich, and rich. It can't really read various degrees of each of those conditions, it's pretty much just one or the other. Now during dyno-tuning, they install a wideband O2 sensor so they can get an accurate reading. Not worth it to buy one yourself though. I hear they go for well over $500, compared to $20 for a normal one.

92 zzz28

If you are interested, there is a DIY WB O2 sensor device out there. It is much less than a commercially available unit. I can't say for accuracy but I bet is close enough for gov't work...If you are doing your own PROM tuning and like to tune for optimum performance and mileage, it may be something to look into. If you just want the A/F gauge for looks, then the WB is not really worth it, like Nixon said...

dj haf

i was thinking of getting an A/F guage because i dont know if im running rich or lean or what... i was hoping it would tell me an acurate reading... does this happen to everyone? or just some ppl? cuz if it's going to happen to me too, wtf would be the point of buying an a/f guage? lol

Chickenman35

Some A\F meter guages will bounce all over the place right when you hit Stoich. Quite common.... Slightly rich or slightly lean and they hold steady. Hit Stoich...and they will bounce up and down. Not a real big deal. With your CC carb...as soon as you cruise or idle it adjusts the mixture excactly to Stoich...and you get the bouncing.

Edit: K&N mentions this in their literature.

Confuzed1

iTrader: (4)

Thanks for all the replies. I read the Auto meter booklet, and by reading it, it seems like it's not very accurate at all. I was hoping to really "Dial in" the perfect ratio during idle to smooth it out, as well as using it to help get the best combo for rods/hangers.

Don't get me wrong, the car runs great and hauls a**, but ever since I got it running, it has a slight surge at idle. Whether it's just due to the cam, or something else - I don't know.

I know exactly when my car goes into closed loop - just listen to the idle...it'll sound nice and smooth - then suddenly it'll start to surge between 800 and 850 RPM's.....just enough to be really annoying.

I've set the dwell at 30-35 degrees on the M/C solinoid, TPS voltage is normal, CTS replaced, egr replaced, O2 replaced,changed intake/carb gaskets like three times. Timing set at 10 degrees BTDC...no dice.

Anyways - so far as the A/F gage goes, I guess I'm runnin stoich as hell, cause it bounces all over the place at idle......and at part-throttle...and at night when it's almost as annoying as the idle! ...those lights in the dark are pretty distracting!

MrBill

One of the reasons those gauges bounce all over the place is because they are trying to use a linear bar-graph LED driver to measure the non-linear signal of the stock O2 sensor. It don't work, as you all well know by now. The fact that it "bounes back-and-forth" is not necessarily a problem, as far as closed-loop control systems go. ANY closed-loop system will always exhibit an oscillating error signal, that's what makes them work and that's what you're seeing.

Ken73 and I have come up with a solution to much more accurately monitor the NB O2 sensor signal. Once I get the prominator going in the next couple of weeks I should have enough parts to put a couple of AF gauges together and see how it works out.

Bill

Nixon1

I know exactly how that goes, buddy. I'm still working the ghosts out of my machine too. Idle surging, high rpm stumbling, occasional backfire at rapid 1/4 to 3/4 throttle change, jerky behavior on deceleration... Put in new TPS, EGR, IAC, CTS, plugs, wires, cap/rotor, ign. coil.... There's always something..

MrDude_1

im not sure about the computer controled carbs, but on all of GMs FI systems (for 3rdgens) the computer cant keep it perfect... so it just bounces it between slightly rich and slightly lean...


but when you floor it, it goes into oopen loop and that is normally rich..... so there you go...that would account for exactly what you are seeing..

dj haf

well should i get a fuel pressure guage instead of an a/f guage? wouldn't that be more accurate?

MrDude_1

that would tell you your fuel pressure.


fuel pressure and a A/F gauge are two totally diffrent gauges.


teh FP gauge will tell you what pressure is being sent to the carb or FI.


the A/F gauge is the amount of air left in the exhaust... more air means you're lean, and less means you are running rich. because you have a narrow band O2, it can only say really rich, rich, lean, really lean..... the computer bounces it between rich and lean to keep the avg about right..... at WOT, the computer ignores the O2 and dumps the amount of fuel the chip says in there, and it usually makes the gauge peg out at rich or really rich.

to tell a more accurate number of what it is, you need a wideband O2. a wide band can tell you how far you are off, and can even give you a number... athough it will still bounce around just the same when the car is in closed loop... that bouncing is normal. its how it works.

Kingtal0n

Let me add some information to this post, which may or may not help.

The most IMPORTANT THING about hooking up the A/F Guage is the ground wire. If the thing isnt grounded DIRECTLY to the battery, its going to give you a nasty flicker.

Now what your describing sounds alot like a screwy ground flicker, and since most people do not ground their A/F guage directly to the battery, they get it ALSO, and assume this is NORMAL.

THIS IS NOT NORMAL!

Only 1 light should be on at a time. its going to bounce around a bit, due to the innacuracy of these O2 sensors, but it should not FLICKR wildly, that is a sign of a bad ground.

Confuzed1

iTrader: (4)

You're right!! I don't have it grounded directly to the battery...it's going to the steering column......maybe I'll try that!

91GTABird

What i Stoich?

demonchild

when the air/fuel ratio is perfect for atmospheric conditions and other factors taken into consideration.

Nixon1

Talon....does the ground thing apply to other aftermarket electric gauges too? Just curious because I jimmy-rigged up an oil pressure gauge to make sure I had decent pressure, etc. and the needle would sit a little wobbly and then it started bouncing violently back and forth between 0 and 100 and finally just hit 0 and sat. I fiddled with the power and ground wires and still got no response from the gauge.

Kingtal0n

Well NORMALLY a bad ground in ANYTHING will cause weird things to happen...

for instance My ECU had a bad ground, and suddenly one day it decided to lock open all the injectors at once and fill my cylinders full of fuel hydrolocking the motor.

i also had a bad ground on my engine block from the battery... so when the car got hot the starter would not turn the motor over.. (heat builds resistance which lowers voltage and voltage = Amp X watts which starts your car) so i figured it was the starter for about a year till i replaced the ground cable and suddenly my hot start problems went away.

guages that work with resistance and voltage (like the o2 sensor or a water temp guage ... ) can do funky things if they are not grounded right.

the reason i said grounded DIRECTLY to the battery is because most grounds on a camaro's chassis i find to be inadequate unless you have run a million of your own ground straps, which i would rather just run a distribution block through the firewall that goes to the battery and hook everything up at that point.

and you definetelly dont wany ANYTHING grounded to the same wire(s) as the ignition is grounded too. ever hear people complaining about noise from their ignition in their radio? ground issues.

the ECU can pick up ground noise and will begin to screw around if it isnt grounded perfectly well. anything can get screwy.

grounding crap properly is almost always overlooked by everybody. you would be AMAZED at the difference in the quality of a well grounded ignition, and a half asses grounded ignition. wonder why its missing like that when it gets hot? you dont even notice it, but that explains the rich smell coming from the exhaust even though your mixture is fine and your ignition seems to be working fine too... i just dont get it...

Kingtal0n

oh and on the guage issue, you probably hooked it up backwards or had voltage in the sender line, which would cause what you described and fry the guage.

Confuzed1

iTrader: (4)

I agree...but as I said, it's grounded along with factory wiring on the steering column. But I will try grounding straight to the batt. to see if it makes a diff. I do know the installation booklet didn't mention it...

Nixon1

I had all the wires hooked up straightaway....S to the sender, + to the positive on the battery, - to the strut tower. Although the damndest thing was after I disconnected all power sources from the gauge, when I moved it from back near the firewall on the driver's side, it started freaking out again like it had power, but it wasn't connected to any power source, and as far as I know it doesn't get power through the sending unit.

Kingtal0n

as i said before you may have got voltage in the sender line which would have fried your guage and caused that.

Nixon1

Damn...I think I lost the receipt. This little sucker had better still work. And lemme guess.....no internal fuse right?

metalhead212121

Do you have any updates for us Confuzed1?

Dan

Kingtal0n

they are super picky! Just today mine started acting stupid, wouldnt go over to rich. i played with the ground wires, first to the batt, then to the chassis, then to both, man what a joke.

the trick was to give it its OWN ground wire, to the battery and chassis, where nothing else uses that wire. and its still acting stupid, when i turn on the A/C I lose the lean side of the guage.

I guess its time for a WBo2.

metalhead212121

Are you serious?? Are you saying you had to splice the ground wire in half and run one part of the wire to the negitive side of the battery and the other to a good chassis ground???

Dan

MrBill

ummm...no, Volts = Watts/Amps

Kingtal0n

Just put it this way. The narrowband O2 sensors I have dealt with have been insanelly picky with me. Some like a direct ground to the batt, some dont for some reason. some dont want to get on the same ground as some other wires, and some wont work if they share the ground with the O2 sensor (on a 1-wire that would be a ground near the header.) It took a few WEEKS to get mine working the way its supposed to. Like i said before, they arnt supposed to be flashy with multiple lights lit up, they arnt supposed to spaz out when you turn on your headlights or A/C. they arnt supposed to insanelly drastic in their changes, and typically they seem to work really well when they want to. Other people have compared WB-O2s with Narrowbands and you can definetelly see a trend in rich-rich and lean-lean between the two. It can be a usefull tuning tool if it works the way its supposed to.

<b>Volts = Watts/Amps</b>
Man I took that class so long ago...
I was thinking that volts X amps = watts; and it does. but thats not what i wrote

MrBill

heheheh, Ohm's law bites again I feel your pain man...it's tough to remember all those silly little formulas if you don't work with 'em every day.

Regarding the ground deal...it seems to me that since the O2 sensor is a voltage source relative to it's own ground, that grounding the meter as near to the O2 sensor itself as possible would be ideal. Since that's not really feasible then the best choice I think would be on the back of a cylinder head on the same side as the O2 sensor...or even a rear exhaust manifold/header bolt...whatever gets closest to the O2 sensor itself. I don't know about the F-bodies...but on most of the Vettes the ECM's O2 "Signal" ground is just that...on the back of the cylinder head on the same side...for just that reason I would imagine.

Back to Confuzed1's original comment:

For a regular linear-sensing A/F meter...I'm afraid that IS normal.

metalhead212121

After all this time I still have questions... On a side note this seems like a pretty informative thread...

Im finally getting around to wiring my Air/Fuel Pod in and it says to splice into the O2 sensor connector on the wiring harness and NOT on the signal wire itself. Autometer says to do it this way because some O2's use a shielded wire.... How did you guys wire your O2's in? Did you "tap" into the O2 sensor wire or did you "tap" into the wiring harness? Lastly (sorry for all the questions) did you soder your connections at the O2 or did you use one of those "-taps".....I think thats what they're called...



Later..

Dan

metalhead212121

anyone?

Kingtal0n

I ran my ground from the A/F guage to the battery, then from the O2 sensor to the battery.
I ran my power wire from a switched 12V source and "Y-spliced" it to the sensor AND the guage.

The Signal wire from the O2 sensor runs into the ECU wire via a "crimp connector", which also contains with it (twisted onto it) the signal wire for the A/F Ratio guage. so yes they are spliced together... but think about it your going to have to connect it SOMEWHERE you cant just plug it into the ECU directly...

Biggest problem i can see is the ground. if you have tons of things running directly to the battery you will also wind up with interference at the guage/ECU. Ive noticed finding a clean ground is the most important thing when dealing with the guage itself, but the O2's ground, unless redundant (4 wire O2) is going to be through the engine itself...

Stekman

I have Nordskog/Intellitronix guages. I dont know how differently the hook-up procedure is, but they tell me to ground directly to the block. I dont know if that is so for their o2 sensor/AF guage.

Confuzed1

iTrader: (4)

Wow....this is from a while back. I can tell you with certainty that I've had mine for a year, and it's honestly the most useless gage I've ever bought.

Sure it well let you know if it's running extremly rich, or very lean at WOT but you can't really use it as any type of tuning tool due to it's sparatic readings at idle. The sensor cools down too quick at idle. If I had to do it over again (which I may), I'd rather have a vacuum gage or maybe a volt meter.

Not to mention it blips around so much at part throttle, it's distracting esp. at night!! It's mounted in my A-pillar (daul pod).

metalhead212121

I understand that... I was just curious whether you guys cut the insulation away from the 02 sensor and then tapped into it from there OR you tapped into the wiring harness connector (which was my main question to begin with)...sorry to be a PITA. I can understand your frustration Confuzed1 but Im kinda screwed now..I have the guage and the A-Pillar so I figure I might as well install it and see how it works for me. Later..


Dan

Confuzed1

iTrader: (4)

You need to tap into the cars wiring harness where it plugs into the O2 sensor. Just don't tap into the wire that comes with the sensor itself, or at least that's what my install instructions said.

And as mentioned above, make sure you have a good ground, although it didn't make a diff on mine.

Hope that helps!

metalhead212121

I dont understand WHY its not good to tap into the sensor itself? Any thoughts?

TIA

Dan

Confuzed1

iTrader: (4)

If I had to guess, I'd say first it's a much stiffer wire, maybe even solid for low resistance. You'd most likely ruin it if you were to tap into it. But just a guess.

vernw

iTrader: (2)

I had one of the Nordskog gauges for awhile. Went with my truck when I sold it. And they always jump aroud a lot, all you can do is watch for trends (lean most of the time vs. ruch, etc.)

As for your wiring question.....

I suspect they mean for you to tap into the O2 sensor's harness/feed wire BEYOND the connection where the sensor plugs into the harness (farther away from the engine). I know I'm not saying it very well, but what they're trying to avoid you doing is taqpping into the wire at a point where if you change your O2 sensor your gauge connection would have to be changed too. As long as you splice in so that the sensor can be changed w/o affecting your gauge then you've done what they are telling you. You're reading too much into the directions!

Have a Great Day!!!



. --- Vern

Nixon1

You never know too.....tapping into the O2 sensor wire, the wire might be so sensitive that tapping into it may cause an irregular reading to go to the computer. For instance, when I ran TWO feed connections to ONE oil pressure sender, both gauges read abnormally low--but when I ran one feed alone, it read fine.

91GTABird

voltage drop