Tone Loc

iTrader: (1)

I've had a Lambdalink in for a while now.... connected as follows:
Signal to ECU
Signal ground to groud output on ECU
Live form *** lighter
Ground for bolt left of gear stick

At times the lambdalink does as it should.... at idle not lights or just flicking about on the reds.... same at cruise or it sometimes dances about in red and amber lights.... if i floor it it goes to the last green. However sometimes when i turn the ignition on the last green light is on (car is not running!) and it does the same when idling... and when cruising... last green. But part way through the jorney it will do what it should then revert to sticking on the last green.

Is this my dodgy wiring or is the sensor on it's way out. It's a MY93 WRX and the lambda sensor is still in the manifold. I have been thinking of moving it up to the downpipe tho. I know if the sensor is knackered it makes it run rich at idle/cruise... is this what im getting?

Cheers,

Tony.

Tim Bomford

If the sensor is $hagged you won't get any reading at all!

Tim

Chris.Palmer

Not an expert on LamdaLink itself - but have built my own diy AFR Meter - & have experienced a similar problem.

I think its a problem with the Display, as I would be very surprised if the Lamda sensor is giving a reading when engine not running (when o2 sensors break they would under read not over-red).

To help me does your AFR display in Bar mode (ie multiple lights lit) or dot mode (only a single LED lit)?

I've found that by fitting a 2.2uf tantalum or 10uf Electrolyte Cap between the LED positive rail & ground cures some spurious LED related issues.

Chris

{edited to say - using seperate grounding points may be adding a Ground Loop - Using the same earthing point may help}

[Edited by Chris.Palmer - 10/31/2002 9:50:18 AM]

Tone Loc

iTrader: (1)

The display is one LED at a time. The instructions say do NOT connect the two earths to the same point. Its weird that it's ok at times then not. What would cause the display to show rich when the engine isn't running?????? I may put a mulitmeter on the ecu signal when the ignition is on....

Just looked at the wiring diagram/diagnostic bit for the early ecus and it says for the oxygen sensor that:

Ignition off : - not output (obviously)
Ignition on (engine off) : 0.6V
Engine on : lean - 0-0.2V rich - 0.7-1.0V

So the display should be showing something with just the ignition on.

Think im gonna have to double check my wiring and possibly rethink the groubding points.

Tony.

Chris.Palmer

What the LamdaLink Displays is based on its calibration.

My DIY AFR only displays 700mv - 900mv - so with ignition on you see nowt.

With engine Running & Lamda cold I see nowt too.

Putting a Digital multimeter on will confirm your lambda sensor is fine.

I still think its the display.

Tone Loc

iTrader: (1)

Chris... do you think it's faulty then????

Tony.

AndrewC

These devices are very sensitive to noise, both on the earth and the Lambda signal, also, you will only see a decent reading on the DVM with ignition on and engine off or when the ECU goes open loop, the voltage in closed loop changes to quickly for a DVM to keep up.

Forgive me if you know all this already.

Andrew...

PS. Use the value in the ECUs memory, that's what I do

Chris.Palmer

I'm guessing sensor is fine - wiring to display or display at fault.

Still not sure why they state seperate grounds (maybe when connecting directly to Landa sensor rather than ECU)?

Use the DVM to prove the sensor first.

You can then test the display by disconnecting from the lambda/ECU & simply shoving 0-999 mv up the signal wire - if you put a dvm on this signal you'l be able to exactly work out oits calibration too.

Could try using common ground & maybe a 10uf electrolyte between +ve & -ve to smooth any noise.

Chris