J4CK50N

Hi all

Just fitted numerous gauges this weekend :-

Boost
Oil Pressure
AFR
Knocklink

All seems to be ok with everything but I have a query with the AFR gauge

Firstly here it is



It never gets above slightly rich on the gauge (the first Amber light). Surely this cant be right.

What I was wondering is what could the problem be? MAF? O2 sensor or gauge not wired up properly?

Any help much appreciated!!

Cheers

J4CK50N

mutant_matt

Where is it on cruise? Around the middle? What you need to realise is that as the Lambda sensor heats up, it reads lean so try this. Cruise along a fast straight road at about 50 for say 5 mins. This should enable to LS to cool down. Now floor it and keep it pinned as long as possible. It should read close to max richness for at least few seconds until the sensor starts to heat up at which time it will read increasingly less rich....

Matt

J4CK50N

Thanks m8

Will try this and let you know how I get on, might have to be a motorway though as up here in Yorkshire we dont have straight roads!!!

Cheers

J4CK50N

tweenierob

Matt, not quite so mate....

The lambda should read accurately unless boost has been on for at least 2mins, unless the lambda is shagged of course.

I have worked on a large number of cars with AFR gauges running from std lambda's and tbh they only start to under read after about 10mins of very hard driving.

The above 2mins is worst case.

Rob

tweenierob

P.s. get a multimeter on the signal wire from the lambda, get a co-pilot to read voltages whilst you are driving and make sure they are correct.

Rob

David MY99

this AFR gauge is not ideal, the steps it takes are to big to get a good picture of the mixture. The best you can do is calibrate it with a multimeter so you know which light stands for which value.

Low readings usely come's from a bad earthing wire
I prefer the apexi AFR/turbotimer pen which let's you monitor it digitaly

tweenierob

The autometer AFR gauge is also a good choice cost wise, however.. These gauges are only for monitoring purposes so uless you are looking to adjust the fuelling the one above is fine IMHO.

Rob

J4CK50N

Thanks for all the quick replys

I am only wanting the gauge for monitoring purposes, I wouldn't even knnow where to begin adjusting the fuelling guys!!

So, so far suggestions are :-

Failing O2 sensor
Bad earth

The earth that I have used is actually one that has become redundant at some time behind the stereo console area so I would presume that this would be a good earth as it is not corroded due to being inside the car - please let me know if I am mistaken.

I will try and borrow another O2 sensor from somewhere to see if this makes a difference and obviously if it does will buy another one!!

Once again thanks for the replys - if anyone has any further suggestions please do not hesitate to let me know

Forgot to ask also - if it is Lambda sensor knacked would that still underread on WOT?

Cheers

J4CK50N

[Edited by J4CK50N - 1/5/2004 4:41:36 PM]

J4CK50N

Any other suggestions as to what to try - as I wont be doing anything with it till weekend as unfortunately Work and Football training take up my dayd and nights!!

Once again, thanks a lot to everyone who has helped me so far!

Cheers

J4CK50N

greasemonkey

By far the likeliest explanations.

It's possible that you could be. Earthing on the Impreza is notoriously inconsistent (which is why earthing kits make a noticeable difference). To rule this issue out, you could try getting hold of some wire with high temperature insulation, cleaning the lambda sensor body and clamping one end of the wire to it with a jubilee clip. Then run the other end through the bulkhead to your AFR meter ground connection.

Process of elimination always a good idea.

Usually, yes. Is your fuel economy absolutely pants, even when you're not booting it?

Just for a bit of clarification, what do you see on the AFR meter when you're just pootling along off-boost? Do you see the voltage peaking and troughing a couple of times a second, do you see a steady reading, or no reading at all?

mutant_matt

Tweenie,Not the case on my 5000 mile old MY00 that I had an AFR gauge on. 30 secs to 1 min max on boost before the LS started reading lean....

Some good comments from Grease there (as usual )

Matt

tweenierob

You running 3bar of boost Matt?

Seriously though, you can also take an earth from the ECU.

Rob

mutant_matt

Nope - at the time I was running 1 bar (relative)....

J4CK50N

Once again thanks a lot guys!

Will try all of these things at the weekend!

Cheers

J4CK50N

Edited to say that Consumption does not seem that bad - 270 miles to a tank when not booting it doing 10 miles to work and back!

[Edited by J4CK50N - 1/6/2004 12:46:11 PM]

Dark Blue Mark

As stated, it doesn't matter what lights are up, what's important is the voltages they represent. f you didn't get them with the gauge, you will have to inject a signal into it at incriments to find the min / max. You then need to find the limits of the o2 sensor to see what lean and rich actually look like.

MB

Dark Blue Mark

PS, when my AFR display played up, it was the MAF sensor

Assume you have used the correct signal wire? If the display doesn't move you may have the wrong one, ie fixed voltage output.

MB

MarkB1

Just got a autometer AFR gauge, can anyone tell me which is the signal wire from the lambda, any pics of the connection/installation would be great.

greasemonkey

Which wire you want depends on what model year of car you have Mark. Are you going to tell us or are we supposed to guess?

MarkB1

The car is a MY01, thanks for the prompt

MarkB1

up

mutant_matt

I tapped into mine at the ECU but I had an MY00 so I can't help.

Matt

MarkB1

any pics of where you tapped it into please

ZippyEFC

I fitted the same afr meter as J4CK50N the other day and mine is doing the same.Greasemonkey i'm only getting 180-200 miles per tank full of optimax what could be causing this?My car is a MY93 WRX.

Cheers ZippyEFC.

John at J&S

Chassis ground is not the same as battery negative. Battery negative is the reference point. Every other point on the car will be at a higher voltage. You can measure diiferences in voltage between B- and the chassis.

For example, set your DVM to volts, and connect the black lead to battery negative, and the red lead to the point where the headlights are grounded. Then, turn on the headlights, and you will see a measureable difference. Headlight "ground" is not really ground, when you turn them on.

On a four wire O2 sensor, two wires are for the heater, which can be ignored.

The other two wires are O2 signal, and O2 ground, which is usually connected to ECU ground.

You O2 meter should be grounded to O2 ground.

ZippyEFC

bttt for greasemonkey to see my query.