I wouldn't spend money on an autometer guage, or anything else that converts the stock narrowbands sensor into an air/fuel ratio. I stated already that it makes a lot more sense to me to simply look at the voltages coming into the ecu with a multimeter. A $10 DIY is cheap and yes, could be useful ensuring the car is going into closed loop.

I don't like advocating narrowband o2 sensors, because for one reason or another people start getting the idea that it's ok to tune by these. When I say tune, I'm implying WOT situations. Most people don't give a second glance at tuning for cruise, or light throttle situations. If tuning for light throttle is necessary, a wideband can easily be used for that as well.

 

A DMM is far too useful to have permanently mounted in a car. A simple 10-LED meter like mine performs the same function, costs less, is far smaller, and isn't needed for anything else.
By that you sound like you're implying I do. I have never suggested anyone use a narrow-band sensor for tuning purposes. I have always suggested tuning be done on a dyno by a professional with a wide-band. I don't like suggesting people do their own tuning with their own wide-band, as there's far more to tuning that just have an accurate A/F meter. Most people here don't have the knowledge or experience to maximise engine potential and still be safe.

What annoys me is when people make ridiculous statements like "A/F gauges are useless/worthless", because this usually means they don't really know what they're talking about. If you mean "narrow-band sensors shouldn't be used for tuning purposes" then say that! Simply calling them worthless (implying worthless for anything) is BS.

 

I wouldn't advocate permamently mounting a multimeter in the car, I agree with you. In this situation, it would help to diagnose a whacked out narrowband o2 sensor that needs to be replaced. I'm not against narrowband o2 sensors, but they just aren't that important IMO compared to other things you could be monitoring.

I wasn't trying to imply that you suggest people tune thier cars via narrowband air/fuel guages. I also agree, that there is much more to tuning an engine than having a fancy wideband read out.

However, I do think some of the more notable members on this forum tend to be overly cautious in regards to tuning. If someone running minor bolt-on's has a safc and a wideband, assuming they posses an average knowledge of efi, I'd trust them peform minor changes and not blow anything up.

Sure a/f guages can help diagnose problems with a car. I just don't want people to use them for a purpose they weren't designed for. You'd be surprised how many people I know that have tried tuning a car at WOT with an autometer light show.

 

You have more faith than me then. If someone wants to have a go then that's up to them.
I'd just prefer to give people all the info on O2 sensors, rather than just dismiss them because of the ignorance of others. But I think we're pretty much both on the same wavelength here.