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Discussion Starter · #1 ·
does anyone know where the best place to hookup the purple wire?? for the o2 sensor? i want to just splice it at the ecu but dont kno which wire is the o2 sensor. thanx
 

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On 94-95 it's pin 43 (R/BK) for left and pin 44 (GY/LB) for right. This is out of the Ford Service Manual for 1994. This is what I used, and it is correct on mine.

According to an old chilton's manual (8253/26606) page 6-58, for 89-90 it's 43 (DK GRN/PPL) for left, 29 (DK GRN/PPL) for right. Yes, they both say the same color.

According to the same chilton's manual page 6-59, for 91-93 it's 43 (RED/BLK) for left, 29 (GRY/LT BLU) for right.

BTW, I got this manual for $6 at half-price books. The appear to have gotten a bunch of them.
 
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Discussion Starter · #3 ·
do most people just connect it the the #1 sensor?? or have some kind of toggle switch to switch back and forth?? how would this be done??
 

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What you need to do both sides with one gauge is to get a SPDT (Single Pole, Double Throw) switch. You can pick them up at Radio Shack. They have a couple small ones, one with a metal lever, and a black plastic one.

Connect the wires as follows.
left switch terminal: right sensor lead
right switch terminal: left sensor lead
middle switch terminal: Air/Fuel Meater

If you mount the switch so the toggle moves left-right, then when the switch is pointed left, you'll be reading the left sensor. When it's pointed right, you'll be reading the right sensor.

On a day-to-day basis, you probably won't need it, but if you have problems, it can help tell you if one side is off. Easy to do, so why not?

As for two gauges, I'd save my money and just do the switch. If you just want a light show, then you better get two, but they really won't be something that you'll look at all the time, and probably just be distracting. The meters aren't specific enough to be useful that way.
 
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Discussion Starter · #7 ·
ok i installed it and all and now it just reads the last green bar really bright and like barely anything else. when i say barely i mean the rest is really dim. um does anyone have a clue whats up??
 
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Discussion Starter · #9 ·
does anyone else have any info? also when i hold on to the purple wire and my shifter knob , i can control the leds. i guess cuz of electricity and all. but i was wondering if anyone could help me out
 

· heavy weight
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a/f gauge

dark pony if you use a seperate, one wire o2 sensor , welded in before the cats you get a pretty close reading .

when you connect it to an exsiting o2 you get some of the over ride from the computer.


just trying to help .

ken
 
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Discussion Starter · #12 ·
Red Coupe said:
does anyone else have any info? also when i hold on to the purple wire and my shifter knob , i can control the leds. i guess cuz of electricity and all. but i was wondering if anyone could help me out
Um, what? During normal driving, the gauge should bounce back and forth from red to green, and some in the yellow. The only time thos gauges even come close to being accurate is when you're at WOT. If it's staying on GREEN the whole time, you're running a bit rich.
 

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a/f

do you have a two or three wire o2 . if you hook it to the wrong one it will not work right , and can burn it up .

and yes they usually only work 3/4 to wot .

one of the wires is a heater for the o2 .

some computers will regulate the o2 at wot to read rich even if it isn't , thats why it is best to have a seperate o2 for an a/f gauge.

ken
 
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Discussion Starter · #16 ·
Red Coupe said:
i just dont understand why the rest of the LEDs are dimmed. only the last green bar stays lit up
It sounds like you've got it wired wrong. Do the LEDs bounce from side to side while driving?
 
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Discussion Starter · #17 ·
i havent taken it out driving yet. i mean if the gauge doesnt work right when im idling i dont think its goin to work while driving
 

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I like that you can control it by putting yourself in the circuit. :)

buy/borrow a voltmeter. The signal should fluctuate between .1V and .9V and I'd bet you're at either 5V (VREF) or 12V (BATTV), which is the wrong wire. This will burn up the gauge if you don't fix it.

As for the usefullness, I have to agree that it is limited. Since the computer is constantly adjusting, the light bounces all over the place. At WOT, the computer enters open loop mode, so it will peg at all green (rich). If you watch closely, you will also see that the computer cuts fuel when you coast for more than a few seconds (lean).

What it is useful for is determining the mode that the computer is running in, or when there is a problem. It will tell you one of three things:
1) The computer is in closed loop mode. The light bounces around.
2) The computer is in open loop, and senses load (pegged rich)
3) The computer is in open loop or something is wrong, so you're very lean.
Problems will be noticable when it doesn't do what it's supposed to. If it's lean when you floor it, then you might need more fuel pressure, clean your MAF, etc.

I'm not saying they're totally useful, but they're slightly useful for diagnosis and also for understanding what the computer is doing.

Peace,

Barry
 

· The original
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The ONLY thing those air/fuel guages, that hook up to stock o2's, are good for is to fill a hole in a guage pod.

Hook up with Andrew and 302_plus_a_few and see if they will make you a wide band set up. A little more money for parts, and some more for their time/labor and you will have something that actually WORKS. Its a proven set-up that is the best bang for the buck.
 

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If you want a wide band O2 sensor, this is an option. They sell a DIY kit (requires soldering all the components to the PC board), or a pre-built one.

http://www.techedge.com.au/

To make any sense of the readings, you should also consider a real-time data logger, such as from www.tweecer.com . If you're using the stock computer, a wide band won't be any more useful than the one that uses the stock O2 sensor in closed loop mode. At WOT, you'll need to know many of the other sensor readings to do anything useful with the wide band output. Plus, the tweecer will allow more tuning than just fuel pressure and timing.
 
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