I run an 86 TPI 305 and I'm making it a bit more powerful. After modding I'd like to know how everything is doing as far as within the appropriate temps and such. I'm not sure what other guages I'd like (any ideas of what's useful?), but I've always like air fuel ratio guages. My only concern is I'm not sure how practical they are. Also, has any one installed one in their car? I'm not really sure how to do it.

 

I have one in my GTA. As for practicality it's good to have but unlike on a carbed car which will show a constant reading, on a FI engine the reading will fluctuate from lean or nothing to ideal or rich depending on your tuning. It does this because the ECM is constantly adjusting the fuel. When you go WOT it will show a constant reading, mostly rich.

One other thing the gauge will let you know is when the engine goes into closed loop. When it is warming up it will not read anything or an erratic signal, then when in closed loop it will read normal.

I spliced my signal wire to the O2 wire at the ECM. This way all connections are in the car and no splicing in the engine compartment. The wire from the O2 sensor will be the purple wire(412), pin D7 on the 32 pin connector (the big one).

-Ozzy

 

the only thing i used it for was to get a basic idea of where i was at lean/rich under full throttle acceleration. particularly useful with nitrous as you see it peg red you know to get off the throttle.

 

It is a good idea, however if you are running EFI you would be best off with a Wideband, as what the others have described is what happens with a narrow band sensor which is stock, it has a very thin range of whats rich or lean and thus a small change will make it jump a lot, making them nothing more than cool little dancing lights on your dashboard, however a wideband with a broad range of its scale will not just bounce around due to a little change, if the a/f changes a little it will show you it moved a little.

 

Wideband sensor is a good idea but very expensive. Most good dyno facilities use them and so do pro racers for tuning. But for the average Joe it's hard to justify the cost, IMO.

-Ozzy

 

yes this is true, they are coming down in price though. as little as 4-500 and as acurate as the $2,000+ rigs. if your racing and doing it competatively or building motors for tunning you want the best. if your just racing for fun the 4-500 is a real nice tool. if you just want an aproximate idea the basica a/f guage does help some. just do not rely on it.