After my defi gauge install, I have to say that overall I'm very happy with the gauges.

Unfortunately, I do seem to be having issue with my A/F Defi-D gauge. The gauge is wired properly, but seems to not be getting a good signal from the o2 wire coming from my o2 sensor.

I had an autometer A/F wired up previously, and that ran just fine o2 wire.

Here is what happens:

When I start the car, the needles all sweep properly. After that the gauge will just stay at the 6:00 position (off) or quickly rise up to stoich at about 9:00. Then it will bounce back and forth between each reading, never stopping on any value. It's just a fast sweeping motion, about .500 ms.

I had heard that sometimes these Defi-A/F gauges need to have their own separate ground, and if they don't they can have issue. Yesterday I rewired the gauge and gave it its own special ground, but the problem remains.

Does anybody know what the possible reason for this could be? The only thing that I can think of is an incompatibility issue with the 02 sensor. (I purchased a new one 3 weeks ago, and again, it was working just fine with my autometer a/f gauge prior to the Defi-D swap.)

Any and all advice is appreciated.

-Rotary4tw

 

So I looked again at my o2 connection for the gauge. It was connected quite well. When I would disconect it with the car running, the gauge would drop down to 6:00 within 3-4 seconds of the break. When I connected them, the gauge would move back up to the spot in the image.

It will still only give me two readings... off, and 14.7ish.

I have attached a movie of it moving. Once the car gets warmed up it jumps back and forth between the two positions much faster.

Anybody have any ideas?



I also attached a picture of my new boost gauge when the car is at idle. Looks to be about -18psi, is this a decent number? (The previous autometer showed around 16)


http://www.bentarnowski.com/Rx-7/MOV01947.MPG

Thank you in advance!

-Rotary4tw

 

Thats not 18 PSI... It's 18inHG.... It measures vacume, not pressure...

 

You are right! Yah I'm negative boosting 18psi just the opposite direction...

Any thoughts on the A/F gauge? All I can think of is that the new o2 sensor I purchased last month is somehow not compatible with the defi gauge? (Which seems unlikely if the Autometer worked)

-Rotary4tw

 

as unlikely as it may seem, i installed my greddy el meters and bad grounding gave me false readings (weird). I rewired the negative to body and and it works fine now. Hope this helps.If its not rlevant please ignore

 

18 vac is great, ... i dunno on the af gauge dealio, ill look at it tuesday night at Andys crib.

 

Obviously you didn't see my reply in your other thread.. ;-)

A/F guages will bounce around at idle and low load. During these times the ECU is continuously adjusting the A/F ratio in order to properly idle the car without wasting gobs of fuel. The only time the gauge reading matters is when you are on the pedal hard. If it doesn't "go rich" and stay rich at that point then you may have a wiring/guage problem. When you get back off the pedal it will go right back to bouncing around.

Sounds like you'll be over at Andy's tonight, you can check out my guage, it does the exact same thing (at low load/idle).

 

yup agreed, i think thats why people decide that if you're gonna get an a/f gauge, get a wideband..since it measures on and off a load (correct me if im wrong)..

my autometer gauge does that now, i dont even pay attention to it when im off the throttle..im soon taking off that gauge and putting in a wideband soon enough..