Hi all

I am having trouble fitting the LamdaLink monitor. I have followed all the instructions provided and have spoken to Branco at BRD (very helpfull). I have a 95wrx, using the connector block on the side of the engine which has come from the Lamda with three wires. I have tapped onto each of the three wires with no reading at all except from the power connection which just went off the scale. This leads me to believe the Lamda is faulty as it is not giving any signal which can be detected by the LamdaLink unit. It is hard to detect if the car is over fueling as I have the Apexi SAFC and AVCR and the fuling has been played with. I am loathed to part with over £100 on a hunch so I am going to try a universal three wire sensor for a mere £30, in the hope it will provide me with a signal to the LamdaLink.

Sorry to have gone on but I thought the more info the better.

Any thoughts?

Deane

To be certain of the correct wire unplug the sensor and look at the connector pins, the pin for the output signal as opposed to the heater voltage supply and ground is gold plated and obviously different. use a dvm to measure the output by plugging it back in and connecting from that wire to the engine block. at idle you should see a changing voltage from 0 to 0.7 ish.

If you get nothing or a low reading then the lambda sensor is probably "tired" and needs replacing.

Your lambda sensor is in the headers being a wrx Jap spec car, its almost certainly dead, the genuine replacement is very expensive, the UK equiv is the same and just needs the extension lead cutting from the old sensor and crimping (not soldering) onto the new one. Be aware that it will probably strip the thread when its removed and that may need re-tapping.

[Edited by Bob Rawle - 10/15/2001 8:43:26 PM]

Or do as I did, fit De-catted downpipe with UK sensor & save £150 which covers the cost of a downpipe & you get the extra HP.
The UK short lead fits the WRX connector, leads just a bit tight.

Works well for me.
Also did you warm the car before checking the voltage. My lambda sensor has to warm up before the link works.

Mark

Mark,

the Lambda sensor used by Subaru is aheated variety, this means that it will start heating up when you power up the ignition. If you sit there for a minute before firing the engine then it will read immediately.

There are many different types of sensor that can be fitted, from one to four wire. With one wire, it WILL need the engine running, and it MAY cause it run rich at idle when the exhaust gas temps aren't high enough to light up the sensor. With a 3 wire sensor you have a pair of wires for the heater and one for the signal (with ground going via the exhaust metal / bodywork). With a four wire sensor, one can run a separate ground from the sensor to the LambdaLink, this will give the most accurate reading as it eliminates any ground offsets. Interestingly the MoTeC ECU has a differential Lambda input so it too can be connected this way, but the JECS has a common analogue ground (so the LambdaLink will actually read more accurate with a JECS than the JECS does! but with a MoTeC both will read the same).

If you can be bothered to do the work, go get a Bosch LSM11 (part number 0 258 102 004) sensor which will set you back about UKP 110, but it's a very high quality "normal" sensor. Indeed it was used by the Bosch LA-2 lambda meter (about 2 grand worth of kit!) as well as the MoTeC lambda meter and optionally on the M-range of MoTeC ECUs. It is "normal" insofar as it is directly compatible with the input of the LambdaLink and JECS engine management, but it is "special" insofar as it is lead tolerant and has a broader range of AFR response.

For the ultimate in Lambda sensors, have a look at the NTK UEGO or the Bosch LSU series. These are *true* wide band sensors, using a twin zirconium cell oxygen partial pressure measurement arrangement. But be warned, they are far from cheap, and they are NOT directly compatible with the JECS or the LambdaLink. They are directly compatible with the MoTeC M800 series ECUs as well as all the interesting Pectel ECUs. Short of carrying a gas analyser on the back seat of the car, they are the most accurate way of measuring the appearance AFR (you cannot directly measure the true AFR with a lambda sensor, it does not do true gas analysis, only oxygen partial pressure). Just to put this into perspective, when recently mapping an engine on a bench dyno, we decided to trust the ECU readings (with an NTK UEGO) over those presented by the two-grand MoTeC LambdaMeter.... one other advantage of these units is the astonishing speed at which they react. Conventional sensors have a very long delay between the gas content changing and the output changing... up to a few hundred milliseconds. This would be disastrous for closed loop lambda control on boost; this is one of the reasons that full throttle lamdba control is not used on poduction vehicles. Some race teams, however, run closed loop all the time. This is made possible by the NTK UEG / Bosch LSU series sensors. Engines are mapped for best power, and the lambda value conducive to optimal BMEP is stored as a lambda target for that load cell. Then whenever the ECU sees that the engine is operating at that point again, it will tweak the fuel for any slight errors due to environmental conditions using the feedback from the sensor. The high speed means it's seeing "live" data, rather than what the mixture was live a few hundred milliseconds ago.

Cheers,

Pat.

Thanks a lot guys

All very useful information.

You all must have considerable experience on the lamba sensor problems.

Just one final question, I am running the Apexi SAFC air/fuel controller. Working on the basis that the signal is not correct output for the ecu but does give a reading on the lamdalink, I will be able to control most fuling aspects with the SAFC.

And would it not be best to remove the signal from the ecu so that it does not try to re-adjust or compensate for the differing fuling on high boost and keep all control with the Apexi SAFC.

Any thoughts

Deane

Hi Guys,

Sorry to 'borrow' the thread, but seeing as there are very knowledgeable guys on lambda sensors here...

I have a DSO linked up to my lambda sensor on my 99MY UK turbo, because I am trying to determine whether my induction kit is causing my car to run lean at low revs on WOT. Can anyone give me some pointers on the following:
# What voltage is stoich (approx) with this sensor ?
# What voltage is max power (approx) with this sensor ?

Thanks for your help, and sorry for going a little off topic.

Steve

Steve - did Bob Rawle reply in your earlier thread - maybe with the change to the new board you did not get the email alert? I mean your induction mods thread in drivetrain.

Hi John,

Oh yeah !

You're right on both counts - Bob did reply, and I didn't get email notified. Thanks John & Bob - Back to the other thread !

Steve