Willem

Got my home made AF-gauge working today, lambda sensor was broken, so finally I could read something but I was shocked by the results...

On constant revs it gives allmost all lights, which would mean it is running rich when car is at the same revs, and when it needs to boost, all lights go off, which would mean it is running extremely lean on boost, and it isn't running properly on boost either.

Now maybe I build my gauge wrong and is it inverted, or I have a great problem here, so here's a fact which should be the same with everybody, when I lift the throttle, all lights go off, which would mean it's lean, but what does your gauge read when you lift the throttle??

Thnx in advance!!

Jim Galbally

what sensor is it using, proper wideband?

if not, ignore everything it tells you anyway

Willem

Bolted it out a granada 2.9 V6 this morning, it's a three wire sensor.
The one I had before was a four wire, but that one didn't make any sense, this one does, it reacts on my throttle, so it should be working.

My S2 still uses his MFI, so the sensor is only for the gauge, not for management....

GARETH T

dont listen to anything it is telling you

Anonymous

Nice little project, but UTTERLY useless

Willem

why do manufacturers use them then??? they should do something, don't they????

Jim Galbally

ooooooh, look at the preeeety liiiights



anyway mate, what makes it EVEN MORE useless in your car, is that its an MFi RS Turbo that's as likely to see stoich as i am of getting laid by madonna!

Jim Galbally

willem,

theyre used to tell if the mixture is richer or leaner than stoich (they more or less have 3 settings, rich, stoich, lean) this is used to fine tune the mixture teeny tiny ammounts on cruise conditions so that the catalytic convertors don't break.

utterly useless for performance car tuning

Willem

stoich?? sorry, bad english....

I only wanted this gauge to be able to see if the car is running lean or rich, nothing else, so it ain't that useless to me, car doesn't do anything with it, so what?

Anonymous

So if it reads "FULLY RICH" at 14.2:1 when you are on full boost you will be safe in the knowledge you are running rich.

Nice one



I look forward to your "melted my pistons - bugger" post next week mate, should make interesting reading

Jim Galbally

stoich is the point at which the mixture is burning most efficiently, its the best AFR for emissions. it's 14.7:1

the point chip is making, as that the sensor will read RICH at say 14.5 AFR so you'd think "yeah, i'm safe" but thats nowhere near rich enough for full boost, so you'd melt a piston.


likewise you'd be toodling down the motorway at 70mph and see it read lean at 15:0 and panic thinking OH MY GOD MY CAR's ABOUT TO BLOW UP, but its perfectly safe and normal.

Willem

well, that's what I'd like to know, is my reading inverted, or is it correct(as far as it can be correct)??

For those who have an AF-gauge too, does it drop to zero when you lift the throttle??

Jim Galbally

i have NO IDEA if its right or not, because your car will not be aiming to hit 14.7:1 on cruise. like we said beofre, the figures are meaningless (more so on your car that does NOT use a lambda sensor as standard and is notorious for having SHIT fueling when tuned).

one thing i will say is, that if the reading IS correct, and its genuinely running leaner than 14.7:1 on full throttle, then you have a SERIOUS FUCKING PROBLEM and it'll melt quickly if held flat out

Willem

I'm well aware of that, and I won't be going blind to the sensor, but if I read fully lean when boosting, SOMETHING should be seriously wrong....

Anonymous

Your gauge reads "are you at, above or below 14.7:1"


On full boost, Lean is anything more than 13:1, rich is anything under 12:1

So how does a "you are above or below 14.7:1" bare any usefullness to you?



The ONLY time its useful is to tell you if you are running economically during cruise, and even then it will dance around as wildly as a pissed schoolgirl trying to lapdance backstage at a take that gig.

Anonymous

Yes something will be wrong, but its VERY unusual for a car to drop from 12:1 to 15:1 suddenly.

Normally it will either slowly drop (dieing fuel pump for example) or it will drop suddenly to nothing at all (ie blown fuse)

So most engines will have died due to a lean out slowly enough that you will melt the pistons or burn through the head before you manage to spot it on your gauge.


I learnt this the hard way about 6 years ago, i melted a head by being too lean whilist my narrowband gauge told me "fully rich"

Since then, ive been a wideband boy all the way

Willem

Ok, now I get it, sorry for the slow understanding

What car uses a wide band sensor?? I want to be able to get good readings because it isn't running well on boost.

Anonymous

You cant just fit a wideband, it needs a controller as well.

Its NOT something you can really DIY (unless you buy a techedge kit in bits or something like that)

Willem

When I have a electrical scheme of it with the neccecary used components, I can build it at school, wouldn't be a problem.

Does anyone have/know this?

Willem

http://wbo2.com

Lots of info I see, but has anybody a board layout to build something like this myself???

edited: found it http://wbo2.com/2d0/im/2D0descR5.gif

Rene

LOL @ replies from Jimbo & Chip makes me chuckle

frog

Try flashpoint on here, he's built his own

Willem

Been browsing through the site, software and all is there, so should be able to build my own now too, didn't read how too program the chip, at school we have a sepparate ICD, but maybe this is different, nice base to go on with anyway...

Rene

this song from queen pops up in me head