Air Fuel Ratio Gauge

I just installed a air fuel ratio gauge in my jeep, and I was out testing it and I noticed that when I turn on any high current draw devices such as my head lights, the gauge moves leaner about 3 lights on the guage. it will stay about 3 lights leaner until I turn off the headlights. any ideas on what would cause this... thanks guys...

it is an auto meter gauge with their oxygen sensor that self heats, yeah i have 12v to the oxygen sensor and the ground is good. i don't know what would cause this. the more lights or aux items I turn on the leaner the gauge shows.... please help.

 

Figured it out, turns out I was getting feedback thru the key so i by passed the key and added a toggle switch and no more fluctuations.

 

Interesting, What have you been able to determine with it so far? Running rich wide open? Mid-Range while crusing? What does it use for a baseline to establish rich or lean, What fuel/air ratios are at the high and low ends of the guage? What does the guage indicate as an ideal ratio?

 

X2 on what Brian said...inquiring minds want to know.

 

WHAAAA? How much $$$ was said meter? Pics?

 

I have used them in a couple cars. My daughter has one in her Grand Prix GTP right now. Very interesting to watch on an injected car. Kind of like the Knight Rider car, flashes from lean to rich at cruise as the computer compensates. When the car goes into closed loop at WOT the gauge goes pretty rich on hers. I could up her boost some to use the extra fuel.

On my talon (2 liter 300hp) I was close to the lean side at WOT. Depended on where I had the boost set. Could raise boost right to the point of perfect A/F ratio. Well actually I could boost way beyond a perfect mix and melt pistons.

On a carburated motor that won't see much performance tuning I guess I don't see the need for it? With the injected cars the A/F can be easily and accurately adjusted remotely and on the fly.

The autometer C2 that I put in my daughters car was $55 on EBay. The O2 sensor for the jeep would be additional charge. In the first pic it is indicating almost a perfect mix. It is constantly moving to both extremes on her car until WOT.

 

JeepsRCool, I am curious the charging system in your jeep? I am assuming you feel it was a drop in voltage to the gauge that was causing the drop on the gauge?

 

What it sounds like (if you haven't done so already) is you need to mount a relay or two for the headlights and run them right off the battery.:hurrican:

 

I have every thing jumped to the battery through a simple fuse box and the key only controls dist, fuel pump and starter. i have a alterstart.com load boss 180 amp alternator, i have about 500 watts of forward lights, so about 35 amps of draw.

the gauge should help me figure out what circuits on the carb i would need to change for a better mixture.
on wot it reads just on the rich side so i could tune a little more but on light acceleration i get a little bog so i need to do a little tunning. thanks for the help guys

 

It would be interesting to see what would happen if you hooked the meter up to another power source...say a 12v gell cell or one of those 12v battery boosters then did your head light test again.

 

What I was curious about was where you are pulling your regulator voltage from?

 

voltage reg pulling from key
likely cause of the fluctuations in readings, soon i will use it to help me tune and i will post some pics. i used autometer ATM-3375 gauge and kit ATM-2244.

 

The thing that was causing the AFR to change is something called ground offset. Changing the wiring eliminated the situation. I am wondering how much your setup was. I got my LC-1 wideband setup for 2 bills. Is your setup narrowband or wideband?

 

i paid 94.95 for the narrow band oxygen sensor kit and 56.95 for the gauge.
should work for me, i do plan on going to tbi in the next few months. thanks for all the input, but i still got more stuff to do before TDS 2008 next weekend.