Doesn't the O2 sensor send out an analog voltage that can be read with a voltmeter? I realize it wouldn't be as good as something that stores data but I'd think a bung in the exhaust pipe, an O2 sensor and a voltmeter, along with a buddy recording readings at various speeds and loads would give you a fairly decent shadetree idea of what needs to be changed.
I've been full of crap before today...is this one viable?
A regular 'O2' (Lambda) sensor only varies about 1 volt from as lean as it can measure to as rich as it can measure. It's at it's most accurate right at stoichiometric, 14.7 parts of air per 1 part of fuel, and reads about 1/2 ratio to either side. Or that's what I read anyway (various texts, I don't rely on the 'data' about other's products from a .com website that's trying to sell you a compteing product). Not saying I couldn't be wrong, but it's in all the print I have read about it.
A wideband (depending on whoose setup you're running) is quite a bit broader in it's sensitivity (from the single digits up to the high teens on A/F). But it takes a controller and the way you describe would require either a video camera or someone you trust to be accurate to watch it, so you can drive. Yes you have to watch it that close, if you're not recording it, as it has a tendency to vary alot, especially in initial testing.
FWIW, I haven't checked in a while but the sensor itself was over $100 + a bung to put it in with (not much) + a controller was over $100 (I hope they've come down, or maybe the Megasquirt crowd has sorted something out for that, haven't looked there for that). So to that you would add, whtever display you have / want (one of those jumpy LED things, or a nice twitchy analog needle). I won't say it's cheap to buy the whole setup that can record, but they don't usually break, you could get one used (it's consumer electronics, should cost between 15-50% of 'new') or if nothing else your local car club might be able to afford one (get the clamp on tailpipe adapter, no welding or drilling).
Not trying to be snide, or nit pic, just throwing out what I've seen. I've had the racing habbit for all my adult life (so far) and caught it before I could drive so I've always tried to find a more cost effective way to do things, cause you can't afford much speed equipment mowing lawns.
FWIW JC Whitney used to sell a tailpipe sniffer for $100 ish. I ordered one years ago, they were on permanent back order and I haven't seen them in the catalog since. Anybody know how accurate they were?
