AIR and Fuel gauge help

[RiceNmotioN]

i am trying to install an a/f meter on my 92 HB and i am connectting it on my ecu harness...

which one do i connect the purple wire from the gauge to the wires comin from the harness... i am useing a wire clip so i am not splicing the wire....

[Turbolscivic]

Originally posted by RiceNmotioN
i am trying to install an a/f meter on my 92 HB and i am connectting it on my ecu harness...

which one do i connect the purple wire from the gauge to the wires comin from the harness... i am useing a wire clip so i am not splicing the wire....

well......to begin with, you have to hook it up to the o2 sensor...
second of all, you will want to solder the wire to the sensor wire...if you want to know what color, you are looking for the white wire from the o2 sensor......if you dont do any of these, your gauge wont be very accurate.....

hope this helps

[THRICE]

Ummm...No. He wants to hook his A/F gauge to his Ecu, NOT his o2 sensor in the engine bay. If he was wiring to the actual o2 in the engine bay, then you're right, he would use the white wire. If you are going to hook up to your Ecu I suggest you head out and buy a Chiltons Manual for your car and look up your Ecu wiring diagrams for the o2 sensor. I understand that wire clips are easier to use...if done correctly. Be careful, because they often don't work as well as they are sought to. Just make sure your wrap it nice and tight with electrical tape after you clip the wires.

[Turbolscivic]

Originally posted by THRICE
Ummm...No. He wants to hook his A/F gauge to his Ecu, NOT his o2 sensor in the engine bay. If he was wiring to the actual o2 in the engine bay, then you're right, he would use the white wire. If you are going to hook up to your Ecu I suggest you head out and buy a Chiltons Manual for your car and look up your Ecu wiring diagrams for the o2 sensor. I understand that wire clips are easier to use...if done correctly. Be careful, because they often don't work as well as they are sought to. Just make sure your wrap it nice and tight with electrical tape after you clip the wires.

i realize what hes doing.....im sayin that it wont be as accurate
if its hooked up to the ecu....

[BoarderAJAX]

It doesn't matter where he hooks it up, it is going to receive the same signal, although soldering is always best, i used a wire clip for this application and mine works plenty fine.

Mike

[TheJackal]

Originally posted by Turbolscivic
i realize what hes doing.....im sayin that it wont be as accurate
if its hooked up to the ecu....


its on the same wire, cabin side of the firewall or engine bay...

[RiceNmotioN]

hmmm... still kind of lost so it the white wire on the ecu harness?

[Turbolscivic]

Originally posted by TheJackal
its on the same wire, cabin side of the firewall or engine bay...

ok, the farther away from the 02 sensor you hook the sending unit to, the worse the signal......NO, the signal is NOT the same...
the wire has resistance in it......the further down the wire you attach the sensor, the weaker the TRUE SIGNAL will be......
what youre saying is like saying that the fuel pump gets 12v of power all the time....and it doesnt...the voltage flucuates because of the resistance in the wire.....same with the 02 sensor wire.....same with car stereo equipment......same with everything.......but you know, im not here to argue....

[Mark_H]

I think it's the "fat" white wire.
Thats not much help, but I think there is one white wire a bit bigger then the rest, thats the one you need to tap into.
Mark

[BoarderAJAX]

Put ohm's law into effect, the wire will receive 12V all the time because the resistance does not change. If the resistance changes, then the amps would change, but Volts do not change if resistance doesn't change. It does not matter where on the wire he puts the clip.

Mike

[Turbolscivic]

Originally posted by BoarderAJAX
Put ohm's law into effect, the wire will receive 12V all the time because the resistance does not change. If the resistance changes, then the amps would change, but Volts do not change if resistance doesn't change. It does not matter where on the wire he puts the clip.

Mike

thats where you are flawed....there is no such thing as a wire with 0 ohms.....and the LENGTH of a wire effects the amount of ohms applied......the longer the wire....the more ohms.....YES, ohms do change the voltage like you said.... i mean....do what u want.....but im tellin you it wont be as accurate....even the instructions say to hook it up to the sensor, not the computer....
think theres a reason why??? i do.

[TedR719]

On the 92 Civic it's acually a white/red wire. D14 (second biggest harness)

[THRICE]

Originally posted by Turbolscivic
thats where you are flawed....there is no such thing as a wire with 0 ohms.....and the LENGTH of a wire effects the amount of ohms applied......the longer the wire....the more ohms.....YES, ohms do change the voltage like you said.... i mean....do what u want.....but im tellin you it wont be as accurate....even the instructions say to hook it up to the sensor, not the computer....
think theres a reason why??? i do.


That is false. Wiring has a constant flow of electricity as soon as you turn that key. Electricity is the fastest, most consistant substance known to man. The wire has the same amount of reading, and the same amount of flow the whole length through. The reading is given to the wire from the sensor head, that information is traveled through the wire and to ECU itself. There are engineers that go to YEARS AND YEARS of school to build these cars and if the inforamtion given by the sensor itself fell off the farther it went to the ECU, there would be no use for a A/F reading at all. It's a combonation of common sense and simple physics.

[stu]

Everyone knows that you loose signal strength the further you go from the source. HOWEVER. I honestly don't think that the wires is quite long enough for you to notice a significant difference. I mean, how long could the wire be at the most? Twenty feet? But then again, I haven't had years and years of training in that department.

[THRICE]

Like I said, expert engineers built the car. And if the white ECU wire was long enough to lose signal to the ECU, it raises the question of why would the engineer make a wire long enough to lose signal at the ECU? The ECU is what controls the air/fuel mixture of the car itself. It makes no sense. So I'm going to go ahead and say that even if that wire was over a mile long, it will keep an acurate signal the entire way through. Think about it, when you make a phone call accross state, how long does it take until their phone usually rings? usually about less than a second. but the signal via ground wires is still as strong and clear. I don't know about you, but I would definantly wire my shit up to the ECU before running wires through the damn engine bay. It's easier, and more convenient, not to mention just as acurate as hooking up to the sensor itself.

[oldskoolracer]

but don't forget if you solder it direct to the o2 wire you can
damage the signal that way the more interference the less
accuracy, and if you do go from the o2 buy a sensor that has
no plug so you can solder both at the same time

[stu]

Telephone lines no doubt have in-line amplifiers I'm sure. The signal is also cut in half every time you split it.

[gjcivic]

wire is a resistor, the longer the wire, the more resistance. The small the gauge, the higher the resistance. Electricity is not as stable and consistant as you think. For instance, when installing a DSS system, any runs over 150 feet or so require a line amp... the voltage drops (the reciever must send 18V to the dish LNB) and the signal returning from the dish looses strength. There is a reason that big car audio amps require a large power wire... A smaller gauge wire is going to provide too much resistance, comprimising the performance of the amp, and do to the fact that resistance causes heat, it can cause a fire.
A longer wire run requires a larger gauge wire to achieve the same resistance of a shorter wire run with a smaller gauge.

This being said, I'm sure that hondas engineers used a large enough gauge wire to provide the optimal resistance from the O2 sensor to the ecu, factoring in the added resistance of any connectors along the run. Some one earlier stated they thought that the wire was a larger gauge then the others at the ECU. You will probably receive a difference in range based on where you tap the wire, but the quality of the A/F Gauge is more then likely such that you will never notice.

Are we done splitting hairs now?????

[RiceNmotioN]

can any one still help me? i tried the main white one on the harness no work... the red and white no work.... its a 92 cx.. with a jdm b16a

[TedR719]

D14 is the one you wanna tap, it will be the white/red wire, on the obd2 it's just a white wire but same pinout. Make sure you have a good ground and power to the unit as well. That's the way I have it hooked up on my car...


Originally posted by RiceNmotioN
can any one still help me? i tried the main white one on the harness no work... the red and white no work.... its a 92 cx.. with a jdm b16a

[RiceNmotioN]

is it the same with OBD1?

[TedR719]

yeah same pinout for obd1 and 2 D14 (second biggest harness)


Originally posted by RiceNmotioN
is it the same with OBD1?

[RiceNmotioN]

thanks

[TheJackal]

who gives a shit, a/f is for a general idea not tuning, if you want to tune it to the best of your ability, dont you want to use a wideband o2?