john banks

With those settings you should see the top light on full boost.

To be quite honest I can't remember exactly what I suggested, but the above is sensible.

john banks

After the engine has been warmed (but not thrashed), if you then go full boost you can read the sensor for about 15 seconds before it overheats and reads lean. This is a limitation of the sensor. See the link manual. After a quick thrash it needs a few minutes of gentle off or low boost driving to cool down before you can measure again. It is still very useful, but you have to know its limits. Maybe this is your explanation?

paulwadams_my99

It must be that then John, On way to work it on WOT it stayed on third light, green, with sometimes a flicker of blue on release of gas. However it doesn't take that much of prolonged WOT to start showing just orange. Also when i stopped at a junction for about 2 minutes and booted it away it was on blue solid and then back to green (no3) again next WOT. My sensor seems very susceptible to heat?

john banks

The link manual shows you that you can put a spacer in it to improve the situation. Mine does not seem quite so susceptible.

Now you know the normal behaviour you can make sure it doesn't change when you put the Dawes on.

I gather you can't precisely compare a lambda sensor from one individual car to another - relative results after mods on your car are perhaps more important.

john banks

Lambda sensors are about £50 from Halfords. Never spaced my sensor so don't know. You really want .87V or higher.

Ray T

question to anyone with the dawes afr, What way do the lights illuminate i.e from the black sensor one or the other end and if poss what colours please, i'm trying to fit the unit in my guage pack housing above the dash and there are two positions but the unit has to be inverted, so i'd like to know before i mod the housing.

thanks in advance

ray t

john banks

From 1st to 4th light as above in Paul's post red through to blue if that helps?

Ray T

cheers john,

thats the order sorted, just need to know is the red or blue light next to the dark sensor on the unit.

ray t

mrp

Paul

Fitted Dawes MBC and AFR together. On part throttle red, yellow and green flash momentarily then blue will light for a bit longer. On full throttle I get sustained blue.

(MY96, Jetex 3" SS system and K&N panel running 0.9bar boost)


Martin

paulwadams_my99

The red light is next to the dark couloured lens/light sensor.

I am gonna change me earth first this weekend to the signal earth at the ecu to see if it makes a difference. I'll let you all know my results anyway. Failing that I may borrow a Lambda sensor to see if its starting to fail or use spacers. What boost you running mrp? I am at 16.5 psi with PPP. Like I say though this whole thing seems very susceptible to what I can only gauge as heat. Need to have more of a play with it i think. Got another drive home now so i'll give it another go. So busy tdy i couldn't even get the camera out, maybe tomorrow.

Cheers

Paul

mrp

0.9 bar which is, I think, approx 13 psi.

Ray T

cheers paul
i can file my hole now, and hopefully fit tomorrow, plan to lay in a new earth to the battery terminal, pull the power of the cig lighter wire ( i dont use this wire at moment as i wired the cig socket direct to battery for a solar charger), and pick up the signal from the ecu wire. so i'm hoping the weathers dry tomorrow!!

ray

john banks

Idle is a very complex issue, and that is all I know about it!

The Select Monitor can change your idle speed apparently. I think the ideal is supposed to be 850RPM.

paulwadams_my99

Well its all sorted!

I rewired both the earth and live, with fuse, to the battery and I now get consistent results and its always on blue on WOT. I can only assume that I had successive voltage losses through multiple earths when connecting to the cigarette lighter. The reduced/flaky voltage across the device must have lead to inconsistent readings. Thats my best guess at it anyway

T-uk

glad to hear that paul,wait until you get the dawes mbc on and unleash's rhe beast

T-uk

just thought,if the power is taken from the battery,have you put a switch in the line?,or it will be switched on all the time draining the battery.

paulwadams_my99

i dont think i'd be botthered about it as the drian will be v v small. However its a good point t-uk and john. I'll put a switch in if im ever gonna leave it standing for a couple of weeks.

Cheers guys

Paul

P.S John B get youself in chat mate i see t-uks been coming in lately keeping me up till god knows when!

Otis

Mine just stays on the blue ALL the time no matter how hard you juice it. Me thinks something wrong here somewhere. Any suggestions?

Otis.
MY00 with AE800 ECU

catflap

Humm, well i just put the earth direct the the battery, and it has made a difference the lghts stay on longer, i have run out wire to put the luve direct to the battery.

Do the light stay on all the time or not, anyone

Otis

Just realised AFR goes out when I turn on the sidelights and headlights. We're certain we connected to pin-21 and we have a live and negative back to the battery. Are we sure pin-21 is the one for the signal?

Otis.

john banks

I still maintain that sensor earth is best theoretically and practically.

paulwadams_my99

John,

I would say that that dawes point to connect to the battery is that you eliminate any incorrect resistance. U are guranteed that u have minimal resistance and almost insignificant voltage drop by connecting to the battery. If the sensor has a bad earth then u will be connecting equally to a bad earth, both will then work incorrectly. U will see the same voltage the labmda sees by connecting to the lamda earth but if its running low then your output maybe affected and the lights adversly affected. Two wrongs not making a right. U'll never know which one is wrong.

Cheers

Paul

catflap

Regarding the earth listen to this.

Fitted it today with a little trouble and some help form here.

Attempt 1.
Live from the ecu
Sensor from ecu
Earth from lighter

Result.
Red flickering on cruse, orange at WOT (any gear)

Attempt 2.
Live from Ecu
Sensor from ecu
Earth from Battery

Result.
Red flickering on cruse, lights run up and stay on blue at WOT, i also seem to see more lights, they dance around alot, where as in attempt 1, very little happening.

Conclude (on my car, uk99) best to run it to battery

How are you lote geting the cable into the cockpit, i ran it in with the throttle cable, dont know where else?

paulwadams_my99

catflap,

i ran it through the grommit on the passengers side. Its just behind the glove box. Just drill a little hole.

Cheers

Paul

john banks

I am thinking quite the opposite. Whatever earth the sensor has that is the one I want on my meter as I want to measure what the sensor is doing RELATIVE to its earth not pick up any offsets from a remote earth, which are MORE likely to be affected by load. I thought it was a definite no-no to use an analogue ground distant from a sensor when you are into millivolts in a noisy environment. Happy to be wrong as always Mine is staying on the sensor signal and ground wires to the ECU and has always worked well there. Why do you think the ECU designer bothers to take the sensor earth into the ECU? I bet you anything this is the ground used for the ECU's lambda input. So that is the one I am using.

If there is a small resistance between the battery ground and the sensor ground, then varying loads will cause it to fluctuate. Not so if you connect to the sensor ground.

paulwadams_my99

John,

i didnt mean arument i meant discussion

what u r saying, according to my mate is 100% true! However if the earth on lamda sensor detrioates then both will malfunctuction at the same level. Better to have a measuring device measuring absolute values correctly at all times. Measuring relativitly to the lamda is good but if the earth detrioates then both relatives measument deterioate relatively.

So basically both are fine earths but theroitcally and practiacally the batery earth gives u an absolute reading.

john banks

Sounds like bollox to me. No offence to you or your m8 but I think we have to disagree. Your post seems to be a collection of non-sequitirs.

If the ground goes off on the lambda and you ground your measuring instrument at the battery then you have an error. If you want to measure the lambda sensor the best place to measure is at the lambda sensor. The next best place is two wires connected to that. If you ground at the battery and there is an offset then you have an error. Can't see how you get around this simple fact?

A voltmeter is a collections of op amps connected to a battery. If you measure at the lambda sensor then the nearest to this is to connect the ground at the lambda not the battery. How do you get more accuracy by introducing more resistance in between the device you are measuring and the meter?!

paulwadams_my99

We'll go nowhere with this john My mate is an electrical engineer. I wont prove anything to u. There is no resistance connected directly battery except the internal resistance of the battery which both devices see. I cant see how it is correct to measure relatively than absolute. Im not gonna go on, I have said what u said is true. You get consistent operation through all conditions normally and abnormally and that is the function of a measuring device by taking it to the battery. Perhpas we should write to darren and see if he has a comment?

Cheers

Paul.

john banks

Excuse my pigheadedness, but I'm not going to trust an "authority" on this any more than I would on any subject unless their argument has quality. Otherwise it is a pseudoscientific ill-informed approach and we all learn nothing, and authorities have a nasty habit of being wrong.

Measure the source is what I am saying. If you want to measure a sensor measure at the sensor. If the ground at the sensor is poor then there will be an offset by measuring at the battery.

Certainly no offence intended. Not convinced by what you are saying. Just being honest I think we'll just have to disagree unless anything else crops up. I would be quite happy to be wrong that is not the issue honest

paulwadams_my99

John,

no problems agreeing to disagree

I dont doubt what u r saying as u are a very clever man. Always said it always will.

I dont understand though how there will be an offset if u measure at the battery if the ground is dodgy at the lamda. There is no offset differnce going directly to the battery. You might adversly affect the earth by adding things to it at the lamda sensor.

No offence but i'll take my mates word on this one. Still would be nice to see what darren has to say.

P.S i wouldnt take the word of any mate. But i trust this one as hes my dad! Lets leave it as that. Both our earths are good