hey, im looking into getting the autometer a/f gauge, i know its only usable under wot, and even then you just get an idea of what its running, but i came across a site called gadgetseller.com and they say they can make the gauge more accurate for $30. has anyone gotten one of these "upgraded" gauges? any opions? (sp.) im also planning on getting a egt later down the road, this is just to hold me down till then. thanks

 

up

 

Gay.

Its not worth it...you still have the same thing happening as the regular Autometer gauge...but they just say its more "accurate"...yeaa.

Do you have a S-AFC? If not, get one...you can moniter the O2 voltage through that and theres no need to waste your money on a A/F Gauge.

 

I don't understand how it could be more accurate. The a/f gauge just is a simple schematic based around a specific chip, LM1412, or something similar. It's designed to hook up to 10 leds for a display for the voltage reading. The autometer gauge just uses 2 of these chips, hence the 20 leds.

If this gauge uses the same design, it's most-likely identical in accuracy.

 

look what I just remembered I had..

it's the LM3914 chip.

 

Im thinking that they might replace that chip to have more then 20 LED's...therefore more "accurate"

 

Hey--HX guy--what tranny are you running, just out of interest?

 

The leds read .7v to 1.0v instead of .0v to 1.0v........

All it really does is change the values of each step.
Instead of .05v per step it is now about .015v

 

GSR tranny

 

Well that makes sense, although i'm not sure how much more this will make a difference in the accuracy. It's just a shorter spectrum, right? Then again, that's similar to what a wideband o2 is..

 

could you put that into dumber terms? im not too educated on gauges, would smaller volts make it more accurate? thanks

 

The mentioned scenario would only let the sensor read voltage from .7 to 1.0 , lets
say 30% of the full o2 sweep. The o2 sensor fluctuates back and forth quickly as
the injector signal(pulse) strengthens and weakens. It's a voltage reading transformed into a sequence of lights. This scenario wouldgive you view of only readings from .7 to 1v; which does not sound ideal to me on an oem sensor.

Why don't you just wait and buy an egt!

 

how can you tell your fuel from an egt?

 

What in the world do you mean?

 

Here, the e-mail I got from gadgetseller.com about the mod'd a/f gauge:

Frank,
I just read through the posts on the forum. I think many of the people do not understand the reason I am modifying the gauges in the first place. A "normal" OEM O2 sensor can output from 0-1.0 volts depending on the air/fuel ratio. During normal cruising or idling conditions, the voltage from the O2 sensor will cycle VERY rapidly from about .3-.7 volts near the center of the STOCK Autometer gauges. Here you are seeing the ECU trying to adjust for the ideal air/fuel mixture of around .5 volts. Under full throttle, things are different. The ECU no longer makes adjustments based on this voltage and the reading will not cycle rapidly. Usually it will immediately jump to about .9 volts and stay there as long as the car is at full throttle. A voltage of only .5 volts at full throttle would quickly melt your engine because this is much too lean at full throttle.

I narrow the working range of the gauge to about .76 to .97 or about .01 volts per LED. This is about 5 times the resolution of the stock Autometer gauge for the new working range. This resolution is needed because at full throttle, a minor O2 voltage change is a big difference in air/fuel mixture. In my car (97 Talon AWD) for example, I run about .90 volts for everyday driving. At about .80 volts I would probably get detonation and melt my engine eventually. A difference of .1 volts is the difference between running good and destroying an engine at full throttle.

The drawback with my modified gauges is that they are useless at idle and while cruising. The working range of the modified gauge is above the normal voltage cycle usually seen while cruising. I am willing to give up this feature because while cruising, the ECU will make the fuel trim adjustments necessary for proper combustion. It's at full throttle acceleration when the ECU does not make fuel adjustments that you need to watch your fuel mixture carefully. How many people have you ever heard of melting an engine while just cruising? If an injector or fuel pump begins to fail, it should show up immediately by seeing a lower than normal reading at full throttle.

I saw someone mentioned using an AFC to monitor your O2 sensor voltage. This does work with a couple drawbacks. First, it is small and difficult to read especially while doing 110mph down the track/highway. Second, it is a little slow reacting to voltage changes.

 

I had one on my MR2, pretty useless. Girls were kinda in aww by the lights though...

 

I totally understand how his mooded gauge works.

But some of the DSM and Omni guys just use a DVM mounted to the dash to read O2 output voltages.

 

Check it out. Make your own wideband O2 sensor:
http://www.diy-efi.org/diy_efi/projects/diy_wb/

 

where did you get that chip?
I wanna make a din style air/fuel moniter that it just l.e.ds staight accross.
how difficult would that be?
and it it possible to buy that chip somewhere?