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MG Midget and Sprite Technical - Fitting a lambda sensor

I'd like to fit a lambda sensor to the A series to help with fine tuning the fuelling.

Can anyone point me in the right direction to a) source one. Plenty on ebay but are they all the same? and b) a software to read it.

Thanks
Matt
Tarquin

Techedge 2j2. I have had hours of fun with mine. Plugs into a laptop or you can buy a dash display. Plenty of free software around.
The Techedge web site is full of information. http://wbo2.com/
Tim Dalton

I use a gauge and sensor from AFM and have been very happy with it,fitted for about 4 years now.BUT this is a turbo engine,with the sensor about 18'' downstream of the turbo.On N/A I guess you'd have to go after the manifold to 'see' all 4 cylinders.The gauge has a connector for a data logger.
steve cowling

Matt

Are you going for one lambda or 2?
2 would really be interesting as you get a better insight in the charge robbing issues.

And have you decided for a narrow or wide band lambda?
Onno K

They weren't all the same but things may have changed. The Lambda sensor needs to be hot to work. Early 'single wire' sensors needed external heat to get them operational and so had to be up in the exhaust manifold where it's hot. Later sensors had a heating element installed so they could be placed further down the exhaust. Good for the technician tuning someones car because he could just put it in the tailpipe. These had either 3 or 4 wires on them. So you have make sure it matches up with your gauge/display.
Greg H

+1 for the techedge system. Easy to use and great support.
Responded within 15 mins when I asked a question.
System also has channels for rpm and manfold vacuum. If you can get all three then tuning should be a sinch.
Tim
T Dafforn

Onno, I read that a wideband is a better choice, as it operates over a wider range. To simplify things I would rather have just the one. Charge robbing interests me but as I can't really do anything about it no point wasting the time on it!

Will have a closer look at the Techedge system.

Matt
Tarquin

We have an Innovate wide band sensor & gauge, has datalogger connections etc. Works well.
Paul Walbran

Tarquin,

I'm using a DTM4007 AFR meter with a single wire sensor from www.raceparts.co.uk I think it came to 90 quid.

HTH, old bean
a harrington

So it looks like all the sensors plug into some kind of box of electronics? I thought the actual sensor simply gave a voltage reading depending on the o2 content? Can't we just plug into a laptop somehow to read the voltage?
Tarquin

Tarqu's yes

It does read the voltage (almost reads the non voltage, its very low)

I have read the voltage at the plug on the Monjo, when we were having fuelling problems. (result a "new old stock" lambda from a scrap yard)

There are four wires at the lambda, two of which are the heating element wires, sorry, not sure which are which. Its been a while ;) The sensing wire can be read with difficulty (and occasionally burnt wrists) using a multimeter and unbent paperclip so tests can be carried out

But to utilise them on the road you do need the lambda to be read by a "black box", supposedly a megasquirt/jolt type device.

All of which reminds me I need an A series manifold so I can get mine set up too, which reminds me... *







*two manifolds
Bill1

The way i did mine....

I did a simple old fashioned set up...2 wide band 5 wire sensor from boush and 2 AF gauges that are light displays, but # dial faced would be better...i have a 3 to 1 header so i installed the sensors into the 2 outside headers pipes... I was goning to put a 3 rd sensor in the center pipe bu it fouled the steering colum...

I like the 2 sensor 2 gauge system cause it will tell you which carb is out ....where as only one gauge and one senor in the center header down spout will only tell you there is a flaw in the A/F ratio

I was going to add a 3 rd in the center down pipe, but the sensor fouled the steering column... But its a project for the future


Yeah...another gauge, cool

Prop
Prop and the Blackhole Midget

Prop
Realy 2 in the outside pipes?!
How useless is that!
They just show the same situation twice.
You realy need it in the collector where they join or one in center and side to have any use of it for tuning.
Onno K

I can't believe I'm sticking up for Prop, but I think that, for you dinosaurs still running dual carbs, one sensor per isolated carb branch makes a crapload of sense (this coming from a shade-tree mechanic who has never run duals). If, for instance, you have forgotten the # of "flats" turned, no need to start over, just fire the thing up and check your dual lambdas! What could be simpler? Seriously though, when the poop hits the fan and, say, a chunk of gas tank sludge fouls the float valve in a carb, or some other catastrophic failure, you'd know pretty quick (thanks to your dual lambdas on your 29-gauge display!) which one to operate on, wouldn't you? I must say I think the third sensor would however be rather useless (as Onno said: how usless is that!), even for Prop's twisted sense of value-added minutiae.

Per the OP query, my sensor is simply the least expensive one I could locate in the online catalog of NAPA auto parts, I think it set me back all of 18 dollars. Single wire unit, located in the collection branch (sorry Prop) of a 4-1 header. No software, gives all sorts of info while driving (imagine having two or more of them!).

Greg H. said: "you have make sure it matches up with your gauge/display". This I do not understand: voltage is voltage, is there not an "industry standard" for what the generated voltage means? Gauges read volts, sensors generate volts, sounds like an electronic handshake to me, but what do I know?

FWIW I do intend to upgrade to the multi-wire, software supplemented style (as I suspect I'm running overall a bit rich), but that will wait until and engine-out day. Haven't needed one of those in a while: knocking on wood here...


RJ Reeves

Rj
Not with the A-series with it's siamese head.
Knowing what one carb does for both cylinders is a lot more interesting (though only realy gets interesting with EFI)
The carbs should be matched anyway and there for give identical values
Onno K

Narrow band cheap ass sensors can only tell you if you are over or under stoichiometric AFR (14.5:1). And only have one active signal wire; the others, if present, are signal ground and two for heaters. This is just a voltmeter, reading 0-0.9V, with 0.45V being stoich. Easy to read with a voltmeter backprobing the sensor itself.

WB tells you what AFR or Lambda actually is, outside the stoich range, so you can tune at say 12 or 12.3:1 or 17.2 etc. The black box is an active controller, sending stuff to the sensor and getting an altered signal back - it is NOT a voltmeter.

You might use a narrow band and a controllable means of richening and/or leaning the mixture to find which way you need to go to get to stoich, but you will never be able to tune correctly beyond 14.5 +/- .1, which is not in the range for either best power or best economy.

FRM
FR Millmore

I'm with Prop- if you have 2 carbs, siamesed intakes, and 3 exhaust ports you really need a sensor in each exhaust port.

If one carb is rich and the other lean a 3-sensor array would show a spread from lean on one side, average in the middle, and rich at the other end.

A single sensor at the junction would cheerfully say all was well, which is worse than not knowing.
Growler

Thanks growler...

you said what i was thinking and therorizing perfectly

So gow bad is it to actualluy agree with me....i bet it has to suck

Hahaha...sadly it does happen

Prop
Prop and the Blackhole Midget

The shame is nothing a boiling hot shower and a decent scrub with bleach won't cure. ;-)
Growler

Prop has a few you can use until you leave them to your grandchilders.

Prop - Where is the bloody midget?
Fair warning, the next time I go West I will stop in JCMO and kick you butt! And I am starting to feel like traveling again.

FRM
FR Millmore

Funny you should mention that FRM, i got a cly on my head ground out tobight before the sun went down...so 3 more to go, im getting excited agian... Esp now that the heat has broken
Prop and the Blackhole Midget

Do we have to send light bulbs now?

FRM
FR Millmore

I'm thinking that I should be able to plug the sensor into my megajolt, which takes a 0-5v auxiliary input.

Anyone know what voltage output a lambda sensor is?
Tarquin

Tarq-
Not paying attention here - see my post of the 13th, call me back if have more Q's.

FRM
FR Millmore

Yes I saw that FRM, but you only mention narrow band. Do wideband work the same voltage range?
Tarquin

Quoth he:
"WB tells you what AFR or Lambda actually is, outside the stoich range, so you can tune at say 12 or 12.3:1 or 17.2 etc. The black box is an active controller, sending stuff to the sensor and getting an altered signal back - it is NOT a voltmeter."

I don't know what actual processing is going on in the box, but there is a pile of electrogizziers in there.
Also, I don't quite understand why you want to feed it into your MegaJolt - it is just an ignition controller, yes? So what would it do with a mixture signal? My impression is that MegaSquirt might like it, but I confess to not being up on my Megas.

FRM
FR Millmore

On mine I have one sensor after two-become-one-pipe, it "snifs" the exhaustfume for to much unburned fuel and stuff.
Its connected to my ECU(emerald) who corrects itself on that.
Or so was explained to me... :)


Arie de Best

drilled a hole and welded on a nut and presto!


Arie de Best

Hi FRM, the megajolt has a spare input, for example the coolant or under bonnet air temp, which it can then use for adjusting the advance.
I was just going to use it to accept a reading from the o2 sensor which I could just display on my laptop to help with tuning the mixture. Just trying to find the cheapest way of doing it!
Tarquin

Tarq-
If you read enough on that TechEdge site, which was DIYWBO2 when I found it years ago, you can figure out what the output signal would be, but you cannot get it direct from the sensor. You need whatever is the basic function of the controller, then you could feed that to your laptop.

The basic controllers are much cheaper than even the DIY kits were a few years ago, and the display part is a surprisingly large fraction of the complete unit cost. I can't tell you exactly what you need because it takes too long to figure it all out. I did once, but couldn't afford it so forgot the lot. Now all the numbers are changed and prices are much lower, but I am not in position to buy it right now, so I'll wait to reprogram my noggin on this.

FRM+
FR Millmore

This thread was discussed between 06/08/2012 and 17/08/2012

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