|
|
|
I wonder if anyone could give me some pointers here. Basically I want to be able to read the signals from an O2 sensor to see what's going on with the exhaust gases. I just figure it'll be more accurate than unscrewing the plugs and having a look.
So, I've done some reading and this is what I've found:
Lambda sensor output signal ranges between 0 and 1 volt. Outputs below 0.3v mean that the mixture is lean. Outputs above 0.6v mean the mixture is rich.
Sooo... can I just wire up an O2 sensor and connect a voltmeter to the output wire?
I'm a bit confused as I've read that the ECU normally feeds this wire with a 0.45v feed in order to measure the output. Would I need to feed this output wire with such a voltage, and if so, how would I do that?
Are 2, 3 or 4-wire lambda sensors the best ones to use? Or doesn't it matter?
Anyone with electrickery knowledge on here that can give me some pointers? Pillock, I'm looking at you... ;D
|
|
Last Edit: Oct 3, 2007 13:42:06 GMT by BenzBoy
|
|
|
|
|
|
I don't think a lambda sensor changes quick enough to be of any use to us, an ecu see's only rich or lean and move's the whole map up or down accordingly and very slowly. Just my 2c I'm probably completely wrong.
|
|
|
|
|
|
|
Wide band O2 kits have come waaay down in price from the old Honduh sensor days. Nab one of those, and you'll have discreet numbers, rather than red-green idiot lights or minute ticks of a multimeter. Many commercial units have a PC download or real-time USB port as well.
|
|
Team Blitz Ford Capri parts worldwide: Restoration, Road, or Race. Used, Repro, and NOS, ranging from scabby to perfect. Itching your Capri jones since 1979! Buy, sell, trade. www.teamblitz.com blitz@teamblitz.com
|
|
|
|
|
Theres loads on the market which will do this, theres one I can't remember the name of which comes well recommended by a lot of people. Its one of those buy from the US dealies but its only like $250 for the full kit.
|
|
1941 Wolseley Not Rod - 1956 Humber Hawk - 1957 Daimler Conquest - 1966 Buick LeSabre - 1968 Plymouth Sport Fury - 1968 Ford Galaxie - 1969 Ford Country Squire - 1969 Mercury Marquis - 1970 Morris Minor - 1970 Buick Skylark - 1970 Ford Galaxie - 1971 Ford Galaxie - 1976 Continental Mark IV - 1976 Ford Capri - 1994 Ford Fiesta
|
|
|
|
|
Just had an idea, some cars come with a mpg "guesstimator" bet you thats basicly a O2 gas sensor. Could be hacked up and getto install'ed.
|
|
|
|
|
|
|
I thought those OE MPG guestimaters are vacuum gauges like the aftermarket ones are?
|
|
1941 Wolseley Not Rod - 1956 Humber Hawk - 1957 Daimler Conquest - 1966 Buick LeSabre - 1968 Plymouth Sport Fury - 1968 Ford Galaxie - 1969 Ford Country Squire - 1969 Mercury Marquis - 1970 Morris Minor - 1970 Buick Skylark - 1970 Ford Galaxie - 1971 Ford Galaxie - 1976 Continental Mark IV - 1976 Ford Capri - 1994 Ford Fiesta
|
|
|
|
|
Hmm, cheers people! I'd have thought an O2 sensor would have to respond reasonably quickly wouldn't it? I'm not really looking for anything accurate, just a warning when things lean out or go rich. Team Blitz - Where would I find a wide-band kit? Are they aftermarket items? Really, I'm looking for a cheap way to test whether I'm at stoich (or there abouts) at various engine conditions. If the kits cost a lot (i.e.: if I can't make it myself!) I won't be able to stretch to it. I have one of those old vac gauges. It has "Economy Robot" or somesuch funny thing written on the dial. BMW's have a similar thing which I'm guessing would work off manifold vacuum. Not going to be of much use if this is the case as there is going to be positive manifold pressure...
|
|
Last Edit: Oct 3, 2007 15:32:38 GMT by BenzBoy
|
|
|
|
|
Team Blitz - Where would I find a wide-band kit? Are they aftermarket items? Really, I'm looking for a cheap way to test whether I'm at stoich (or there abouts) at various engine conditions. If the kits cost a lot (i.e.: if I can't make it myself!) I won't be able to stretch to it. First off, don't get obsessed with running "stoich". Most cars don't run that great right at stoich. Usually between 12-something and 13-something is the sweet spot. The way you use a WBO2 is to find what combo runs the best, then note the WBO2 reading. You tune via the same old means of power measurement: dyno pulls, ET, or 0-60, whatever benchmark you like. Then you note the WB reading, that's your baseline. You don't keep swapping parts until you achieve stoich! Unless you want a slower car! WBO2 allows you to see incremental changes, as parts wear, or as you change one item at a time, or to adjust EFI or jetting against your baseline. The wide-band aspect gives you the range to actually see gradations, instead of just crude "hi" "low" readings. Where to buy? They are all over the usual suspect sites: Smegs, Scummit, PepRhoids, AutoZombie, etc. If you want, I'll pick one up for you and pop it in the mail. They run around $150-200. Considering the Honduh sensor by itself runs at least $125, build it for fun if you must, not to save $. Cuz you won't save anything. The DIY kits have basically gone dino. It would be like trying to build a cheaper Ironman Timex than Timex builds in asia.
|
|
Team Blitz Ford Capri parts worldwide: Restoration, Road, or Race. Used, Repro, and NOS, ranging from scabby to perfect. Itching your Capri jones since 1979! Buy, sell, trade. www.teamblitz.com blitz@teamblitz.com
|
|
|
|
|
I see what you mean TB. It was just that I have an O2 sensor in an exhaust section I was going to use, so was just contemplating hooking it up for extra info, just as a warning if things lean out and I know to back off. I won't be able to stretch to a pro kit just yet, although I can see the benefits.
|
|
|
|
|
|
|
I won't be able to stretch to a pro kit just yet, although I can see the benefits. Understood completely! No-cost method is to read your plugs. Learn up on how to do a proper plug-cut, get a color chart, an eye loupe, and do a Flintstones old skool WBO2 meter... your M1A1 gummit-issued eyeball! Costs nothing, and tells you a lot about cylinder health and mixture balance when you get good at it.
|
|
Team Blitz Ford Capri parts worldwide: Restoration, Road, or Race. Used, Repro, and NOS, ranging from scabby to perfect. Itching your Capri jones since 1979! Buy, sell, trade. www.teamblitz.com blitz@teamblitz.com
|
|
|
sav
Part of things
Posts: 842
|
|
|
I had been looking at these a few years ago for the same reason as Benzboy and remember saving a link to these. www.nwerdt.com/how-to/electrical/air_fuel_gauge_2.htmBasic led style gauges that use the LM3914 IC. I was going to knock one together but never got round to it. Might be worth a look if you're handy with the old soldering iron.
|
|
|
|
|
|
|
I see what you mean TB. It was just that I have an O2 sensor in an exhaust section I was going to use, so was just contemplating hooking it up for extra info, just as a warning if things lean out and I know to back off. I won't be able to stretch to a pro kit just yet, although I can see the benefits. I don't think a factory O2 sensor will be good enough for this - as mentioned they have a very small range either side of the ideal so you'll probably find it'll indicate either "lean" or "rich" all the time, you won't be able to tell if it suddenly leans out more than is healthy anyway. Something like this: www.vems.co.uk/wideband.html would be more useful but probably a bit expensive/overkill if you haven't got an engine management system to tune
|
|
|
|
|
|
|
You can build a simple gauge to show rich/lean - the guys on clubpolo with supercharged motors tend to run them as on those, running lean = big holes in pistons. There was a chappie on there selling a kit with a few chips and a row of red and green LEDs. Off the top of my head can't think of the circuit but it's not hard at all. I had the diagram somewhere, I'll see if I can dig it out.
As mentioned, these 'idiot lights' aren't suitable for tuning or any real diagnostics though, they're to be treated the same as an oil pressure light vs a proper oil pressure gauge - if it comes on, something is wrong. It won't tell you how wrong things are though.
|
|
Never trust a man Who names himself Trevor. Or one day you might find He's not a real drug dealer.
|
|
|
|
|
As mentioned, these 'idiot lights' aren't suitable for tuning or any real diagnostics though, they're to be treated the same as an oil pressure light vs a proper oil pressure gauge - if it comes on, something is wrong. It won't tell you how wrong things are though. Yeah, that's all I was after really - a kind of lean mixture warning light. Would be cool if you could find the diagram. Then I'll get my ass to Maplin! ;D
|
|
|
|
sav
Part of things
Posts: 842
|
|
|
There are schematics and other useful information from other links on that site I posted above. Bound to find something of use there.
|
|
|
|
|
|
|
Thanks Sav, I had a look at that site and it seems to have the info I was after! I'm basically trying to rig up some sort of warning light so I don't hole a piston by leaning out too much.
|
|
|
|
sav
Part of things
Posts: 842
|
|
|
Aye quite a bit of stuff to read through on there. The multi LED unit looks quite useful as it displays enough transitions to give a fair idea of what's going on.
|
|
|
|
|
|
|
Bog standard lambda probe & a £20 narrowband gauge off ebay (LED type) will give you enough basic info. You can't read it with a typical voltmeter it wont move fast enough to make sense. I run a www.vems.co.uk wideband / egt gauge for mapping & monitoring which is an excellent bit of kit.
|
|
Resident Toyota Geek Current Fleet: HDJ81 Landcruiser, GZ20 Soarer, JZX81 Cresta
|
|
|
|
|
I think a quick google for DIY-WB might bring back some results. ISTR that a lot of the DIY-EFI/Megasquirt guys build them to go along side thier ECUs
|
|
|
|