Lambda (oxygen) sensor retrofit

[Junosi]

Hi all, I'm looking at retrofitting a couple of lambda sensors into my 1995 P38 HSE that doesn't currently have them - they became mandatory later on.

So anyways, my car has the loom in place with the empty plugs there just waiting for some nice new sensors to plug into them. I can tap into the exhaust and mount them myself - those bits are prety easy. Problem is to do with the ECU - I doubt just plugging in some new sensors will make the ECU notice them. I had in mind it would be as simple as using Testbook to tell the ECU to start using them, apparently not ....

I went to Ritter and Melbourne Land Rover today and spoke to them both about it. Ritter didn't know and MLR, after some discussion, decided it would only work if I replaced the ECU with one that talks to lambda sensors.

Does anyone know any different ? I found this on the RPI Engineering site which details how to retrofit the wiring to lambda sensors if you don't have them - but doesn't talk about the ECU part .http://www.v8engines.com/Acrobat/Gems_lambda_sensors.pdf

Thanks for any advice
Clark

[PhilipA]

My GUESS is that the ECU has all the circuitry and all you have to do is plug in the sensors.

The 14CUX computer has it all so the GEMS one almost certainly will.
HOWEVER you will have to make sure that you fit the correct type of O2 sensor.

14CUX has a Titania sensor not the common zirconia sensor and I think GEMS also has them. Ifit does then they may also have a 12MM nut instead of a 17MM. So don't go drilling holes and welding until you have the sensors in your hot little hands.
there is a UK site which has an application list of sensors vs cars.
OK I did it for you.
See this page and you will see they are Titania.
http://www.lambdapower.co.uk/partsearch/az2.asp'manu=Land Rover
Regards hilip A

[Kalincho]

Sorry for my ignorance, though what is the advantage of adding the sensors?

Will it give better fuel economy or performance?

[Junosi]

I need lambda sensors for my 'Tornado' ECU chipset to function correctly - it requires lambda sensors to adjust fuelling correctly. Without lambdas it runs very rich. Previous owner had installed the Tornado set but fuel economy was very poor. I'd like to keep the Tornado chipset as from all accounts I've read they are brilliant with no downside.

[Junosi]

HOWEVER you will have to make sure that you fit the correct type of O2 sensor.

I'm planning on buying a couple off of eBay - Ritter wanted $250 each and Melb LR wanted $900 each for them.... $111 on eBay new ex UK (which I assume are the right ones)
RANGE ROVER P38 OXYGEN SENSOR 1995>1997 - ERR1834 - eBay, Range Rover, Car Parts, Vehicle Parts Accessories. (end time 24-Jan-10 01:57:12 AEDST) (http://cgi.ebay.com.au/RANGE-ROVER-P38-OXYGEN-SENSOR-1995-1997-ERR1834_W0QQitemZ390122758234QQcmdZViewItemQQptZUK _CarsParts_Vehicles_CarParts_SM?hash=item5ad520e05 a)

Mark Adams (the P38 performance chip guru) mentioned something about having a 12mm boss on the exhaust too - so you're bang on there. I think I'll go ahead and order a couple and hope you're correct about the ECU. Worst case is that I have to replace the ECU with one that supports lambdas - 70 pound on british eBay.

[p38arover]

A friend of mine fitted a Mark Adams chip - it was designed for use with O2 sensors and his car didn't have them. It seems Adams wasn't aware of sensor-less P38A. He's since replaced the chip with one designed for our cars.

[PhilipA]

I thought about this a bit more last night, and what probably will be needed is access to a Rovacom or maybe an official dealer machine.

I think there is probably a way to tell the ECU which fuel map to use. In the 14CUX it is a resistor, and I bet that the GEMS will have a check box in the parameters somewhere to change the map.

BTW, AFAIR GEMS ECUs are coded to the particular VIN as a theft prevention measure and also must agree with the speedo. This again will require at least a dealer coding machine. So if you buy one , you will need to spend extra money. I am under the impression that it is very difficult to have a second hand GEMS ECU work in a different car.

Regards Philip A

[Junosi]

RPI engineering say to replace a GEMS engine ECU it must be 'unlocked' or 'rechipped' to be usable. By 'unlocked' I assume they mean via Testbook etc ? They go on to say that it will also require a 'security learn' - probably via Testbook etc again. Either way a trip to the stealer sounds like a must.

As for enabling lambda sensors in the ECU - if all that sort of information is contained in the 'chips' then I'm hoping replacing them with my Tornado chipset *should* enable any newly plugged in sensors. I'm hoping that's the case anyways, Tornado is sure looking for lambda input. My current chipset (P38 original) won't just *see* the lambdas I'm sure without at least a bit of encouragement from Testbook

[81stubee]

There is a setting in the GEMS ECU to change. It comes up on faultmate

The option in Faultmate have on my 1997 are:
- Not Fitted
- Fitted Pre-Cat
- Fitted Pre and Post Cat

I have to get myself a new Oxy Sensor. Ritters quoted me $450

Stu

[PhilipA]

Bingo!!
Set it pre cat as US has pre and post and it will look for 4 O2 sensors.
Sorry if I am telling you how to suck eggs.
Regards Philip A

[p38arover]

BTW, AFAIR GEMS ECUs are coded to the particular VIN as a theft prevention measure and also must agree with the speedo. This again will require at least a dealer coding machine. So if you buy one , you will need to spend extra money. I am under the impression that it is very difficult to have a second hand GEMS ECU work in a different car.

Sorry, Philip. I was wrong.

From a training document I have:


It must be remembered that the New Range Rover features Robust Immobilisation. The GEMS ECM learns an immobilisation code, supplied by the BeCM, each time the engine is started. If the GEMS ECM doesn't recognise the code received then it will immobilise the engine, by disabling the injectors. This means that swapping GEMS ECM's (or BeCM's) from one vehicle to another will invoke immobilisation. Therefore when trying to diagnose a fault do not substitute an ECM from another vehicle.

[Junosi]

I can now tell you that after fitting new lambda sensors ($110 each via UK eBay) the standard ECU is not recognizing them all by itself. Might need testbook to enable them.

After swapping the ECU chipset to the Tornado chipset the O2 sensors were picked up straight away and fuel system is now running in 'closed loop' mode

[Bombardier]

Have you fitted the wide band or narrow band sensors? Heated or unheated?

[Junosi]

er I'm not sure - here's the link to what I bought RANGE ROVER P38 OXYGEN SENSOR 1995>1997 - ERR1834 - eBay, Range Rover, Car Parts, Vehicle Parts Accessories. (end time 23-Feb-10 01:57:12 AEDST) (http://cgi.ebay.com.au/RANGE-ROVER-P38-OXYGEN-SENSOR-1995-1997-ERR1834_W0QQitemZ390122758234QQcmdZViewItemQQptZUK _CarsParts_Vehicles_CarParts_SM?hash=item5ad520e05 a)

Its the early type ones, 4 wires and a square plug. They work and that's the main thing :)

[DT-P38]

To anyone wanting some Oxygen sensors,

I have a brand new pair sitting around doing nothing as I inadvertantly (under very poor advice) purchased them for my sensor-less 1995 P38.

I can't be buggered mucking around with e-bay and can probably tell you what I paid for them (and from who) after digging them out from storage. I would probably be happy with whatever the pom's on e-bay are asking (save yourself the freight charges!) even though I think they cost me more like what Ritters are after.

Anyways, if anyone wants them, let me know and PM me a price you would be happy to pay.

Dave & the pretty pig

[2door grover]

So is the car running better, how much fuel are you using?

[p38arover]

To anyone wanting some Oxygen sensors,

I have a brand new pair sitting around doing nothing as I inadvertantly (under very poor advice) purchased them for my sensor-less 1995 P38.

I can't be buggered mucking around with e-bay and can probably tell you what I paid for them (and from who) after digging them out from storage. I would probably be happy with whatever the pom's on e-bay are asking (save yourself the freight charges!) even though I think they cost me more like what Ritters are after.

Anyways, if anyone wants them, let me know and PM me a price you would be happy to pay.

Dave & the pretty pig

I'd be interested if I knew they'd work with my ECU.

[DT-P38]

Hey P38arover,

Honestly, I would not even know how to tell you if they would work...

I guess if I was a much smarter cookie, I would seriously investigate and consider what they could do for my "pretty pig" too! It makes sense that the brain continuously knowing and regulating how much oxygen the heart needs would be VERY good for overall performance... but I am no car doctor, :eek: and from what I've been reading here, both the modifications for fitting and technology required to activate it all are out of my reach anyway.

Would having them up there help you work it out? I could express bag them to you and if there good you can make me an offer on the price... no doubt I can trust a "super moderator":angel:, and at the end of the day I think its only about 6 bucks for a bag!

Let me know... Dave

[glenhendry]

Rave says (Fuel V8, section 19, page 54) that for post 99 vehicles, pre-cat sensor connectors are orange and post cat sensor connectors are grey.

I just bought two of these (Auto Parts Giant - Land Rover ARBL960903 (http://www.autopartsgiant.com/parts/?Ntt=arbl960903&N=0&uts=true)) from the US and installed them, but they have the grey connectors, and the ones I removed which I assume are OEM have orange plugs. The reason I checked RAVE is because these new sensors are always showing 0v on ODBII scanner (Android 'torque' app). My fuel system is always in 'open loop - low temp' though, regardless of the engine temp (which sits at 92c once warm).

So have I bought the wrong ones?
Dave, what model number/colour are yours?

[DANMAL]

hey guys, one of my sensors is buggered on my 99 model, i just bought a replacement (grey plug) is that the right one, and does that explain y my car would be pinging??? im yet to fit it... also when i fit it, do i have to clear the fault off the computer or would it recognise that its a new one?? im also always runng 98 octane.
thanks Sam... sorry if off topic

[glenhendry]

Rave says (Fuel V8, section 19, page 54) that for post 99 vehicles, pre-cat sensor connectors are orange and post cat sensor connectors are grey.

I just bought two of these (Auto Parts Giant - Land Rover ARBL960903 (http://www.autopartsgiant.com/parts/?Ntt=arbl960903&N=0&uts=true)) from the US and installed them, but they have the grey connectors, and the ones I removed which I assume are OEM have orange plugs. The reason I checked RAVE is because these new sensors are always showing 0v on ODBII scanner (Android 'torque' app). My fuel system is always in 'open loop - low temp' though, regardless of the engine temp (which sits at 92c once warm)

So I have finalised this. The new grey connector sensors are indeed after-cat sensors, as they showed 0v on the OBD readout. I put the old ones (orange connectors) back in one at a time and they instantly started showing values (between 0.1v and 0.9v) and then the fuel system readout on OBD went to "closed loop - using o2".

So I am happy, the O2 sensors are working again, and I am back on closed loop operation. However, be careful when you buy o2 sensors, as the website I bought them off clearly mislabelled them as pre-cat o2 sensors and while they fit, they dont work.

[DT-P38]

Dave, what model number/colour are yours?

Pretty sure the ones I have are grey. Will confirm next time I get under the house and sift through my Rangie bits boxes.

[glenhendry]

For posterity:

Bank 1 Sensor 1 - pre-cat passenger side (Aus RHD vehicles)
Bank 2 Sensor 1 - pre-cat drivers side (Aust RHD vehicles)

Bank 1 Sensor 2 - post-cat passenger side (NAS spec vehicles only)
Bank 2 Sensor 2 - post-cat drivers side (NAS spec vehicles only)

Voltage expected from sensors: 0.0v -> 1.0v (normal operating range appears to be 0.1v-0.9v).

[glenhendry]

Also note that if ECU fault codes exist, it can put the ECU into a kind of limp mode where it goes into open loop fuel mode. This happened to me last weekend when my air intake popped off while four wheel driving, the MAF sensor fault code was thrown and then even after I repositioned it, the ECU stayed in open loop mode until I cleared the fault codes after which time it returned to closed loop operation.

[glenhendry]

Also note that if ECU fault codes exist, it can put the ECU into a kind of limp mode where it goes into open loop fuel mode. This happened to me last weekend when my air intake popped off while four wheel driving, the MAF sensor fault code was thrown and then even after I repositioned it, the ECU stayed in open loop mode until I cleared the fault codes after which time it returned to closed loop operation.

For completeness, this open loop operation was more likely to have been caused by my using LPG to get out to the 4wd area on the highway, and then switching to petrol while wheeling as per this thread: http://www.aulro.com/afvb/showthread.php?p=1573475#post1573475.