**PLEASE HELP** Air/Fuel Guage Problems

[46n2]

I now have a 2nd hand Air / Fuel Gauge and it's not working properly (or maybe at all? ).

Sorry for the long post, but any help appreciated

Now working from the autometer installation guide, i believe that i have wired the whole thing up correctly.

What i did detailed below:

Should be connected to:

The black wire to "a good engine ground"

The red wire to + when ignition is turned on

and the violet wire to the O2 sensor wire at the ECU.

When testing with multimeter prior to connecting the gauge:

The + and - wires sees 12V when ignition is turned to ACC or ON.

This reads ~14V when the engine is running.

Testing O2 Wire:

The +ive probe on the O2 sensor wire at the ECU

The -ive probe on a ground

Multimeter reads 0.2V thru 1.0V when the car is turned on (which from looking at the autometer installation instructions seems correct).

When only the POSITIVE and NEGATIVE wires are connected to the gauge, and the ignition is switched to ACC / ON only ONE LED is lit (on the RICH side of the gauge) - and it is very brightly lit.

When the O2 sensor wire is hooked up to the gauge:

And the ignition is switched to ACC:

The first SIX lights on the gauge light up (from the LEAN side)

And the ignition is switched to ON:

The first NINE or TEN lights on the gauge light up (from the lean side).

In both of the above instances, the LED's have different brightness levels (i.e. one bright, one kind of dimly lit, one bright, one halfway?)

When the ENGINE IS STARTED, the gauge does the same thing and initially does not move.

When the throttle is opened >80% the A/F signal should read RICH (according to the Autometer install guide) as the ECU ignores the signal coming in from the O2 Meter.

when openning the throttle the a/f gauge did not move, and the same # of lights stayed on (approx NINE or TEN).

After 2 or 3 minutes of the engine idling (and a couple of stabs on the throttle) the NINE or TEN or so LED's started to illuminate further towards the rich side, and by the time it had moved to te rich side some of the lean LED's had gone off.

When removing the O2 signal wire the gauge goes back to showing 1 LED on th righ side.

When re-testing the voltage coming through the O2 Wire still shows 0.2V-1.0V

Please help.

I've spent ages trying different gauge wire, and different power sources and grounds, and i've had no luck.

Thanks

Michael

Please help

[NismoR34]

Hi Michael,

I have been using the same gauge in 2 different cars now and it works fine. I think your Grounding and Power wires are correct. The problem may be with A. The wire you are connecting the Violet one to or B. Perhaps the O2 sensor is on its way out?

I remember there being at least 2 different wires coming off the O2 sensor, one of them made the gauge act strangely, possibly similar to your description - but it definatley was not working as it should [prior knowledge of my gauge working in another car helped me know it was wrong]. But when I connected the Violet wire up to the other wire on the sensor it started to work.

I believe when the single GREEN LED is lit up [the last Rich LED on the right] this is just indicating that you actually have power to the gauge, nothing else.

When you are getting more than 1 LED light up and at differing brightness levels its probably just due to the way the gauge works - each LED represents a different voltage detected from the O2 sensor, for example; if .2 volts is represented by the first RED LED lighting up fully and the next RED LED only becomes FULL brightness at .3v - if it is only registering .25v then that would explain only half brightness...if that makes sense!?

I know you said you used a multimeter but just try hooking up the Violet wire to a different O2 sensor wire and see what you get!!! Maybe use your multimeter directly across the the wires at the Sensor end rather than at the ECU - I never touched the ECU when I hooked up mine.

When correctly hooked up: the gauge, during most driving conditions, pretty much just scans from one side to the other as the voltage varies [LEAN to RICH, RICH to LEAN] kind of like windscreen wipers, until you accelerate 80% or more of throttle which then usually goes straight to the GREEN RICH zone until you back off.

Hope this helps

Dale.