AFR / Lambda Sensor Question - GT-R Register - Official Nissan Skyline and GTR Owners Club forum

Josewick · 22nd July 2005, 11:51 PM

I am thinking about havin a AFR gauge or some sort for my car.. But looking at some others, they flick so quickly that you cannot read.. Is it the gauge itself or is it the lambda sensor??

My question is, if the std lambda sensor is not accurate, then how can the ECU rely on its info to adjust the fueling..?? I know people will recommand the WIDEBAND sensor, what is the difference an how does it work? Or should I say can I just buy a wideband sensor to replace my existing lambda sensor? Will it work like that??

I know innovate does a good bit of kit.. In fact far too good that its way beyond me... I only want something accurate and simple.. Don't need to record or anything else.. And i don;'t like the idea of having to drill thru the exhaust and adapt another sensor to it..

Something just replacing the existing one is perfect..

Thanks

Eagle Eyes · 23rd July 2005, 02:31 AM

In my opnion, fitting an EGT gauge is better than fitting an AFR gauge.
Much easier to monitor.
I may be wrong on this but with lambda sensor, it has a tendency of getting
clogged/covered with carbon as a result of prolonged slow driving.
You'll then get inaccurate readings. This is what i find on my AFR gauge.
Although AFR gauge is showing lean, my EGT gauge is showing constant reading
so can't be running lean.

Josewick · 24th July 2005, 09:48 PM

problem is... with exhaust temp.. its different from car to car.. wwhere AFR gauge / meter, i know if its about 14 then its about right...

So.. my question is.... can I replace my existing Lambda sensor with a WIDEBAND one (from bosch) and link that up with the poxy AFR gauge and get an accurate reading??

tweenierob · 25th July 2005, 08:35 AM

Right.....

The std ecu uses the narrowband std lambda readings for vacumn fuelling assistance, the maf sensor(s) give the ecu an airflow reading and the ecu adds fuel according to the airflow but on vacumn the lambda helps the ecu find the optimum afr (stoich).
Vacumn is usually on cruise and any off boost running.
When the air pressure reaches over atmospheric (zero on boost gauge) the lambda has no bearing on fuelling. Basically on vacumn the lambda is closed loop assisting the afr and on boost the lambda is open loop, no assist.

Narrowband sensors generally read 0-1v whereas wideband sensors generally read 0-5v.
Narrowband sensors overheat on boost, which is i believe the main reason they have no impact on - on boost fuelling, plus the narrow voltage scale doesnt help.

Ideally you want to run the std lambda for the ecu but use wideband for display purposes, a std ecu will not support wideband directly.

A wideband system like the innovate one is ideal, it can display true wideband readings but also output a narrowband signal to input to your ecu.

just woken up so i am sure i will add more later but the above might help you understand it a bit clearer.

If narrowban shows lean but EGT is not high, i would suspect the narrowband sensor has overheated.

Rob

Josewick · 25th July 2005, 09:57 AM

Thanks Rob.. you are a star..

OK.....what I am trying to avoid is to get one that I have to muck about drilling a fitting onto the downpipe then blank it off after use..

So .. if..... I can use a bosch wideband one (hopefully the plugs are the same).. I can just use that with an aftermarket AFR gauge to get a good reading..

But the concern now is.. if they have different voltage output, the range is different and the ECU will not work with it too well..

When you say Innovate uses a wideband that has narrowband output and can display a wideband signal.. Is it their control box that does the convertion or the sensor itself.? COs i remember reading their product details, they also use the bosch wideband sensor..??

Thanks

tweenierob · 25th July 2005, 12:39 PM

I think maybe you are confusing the sensors...

There are different bosch sensors, if i remember rightly from my GTIR days there is a bosch sensor that reads 0-1v and doesnt overheat much. This also has a nissan plug on it but is not true wideband, i am assuming that it is known as a wideband sensor as it doesnt overheat and will read high temp AFR's still but on a 0-1v scale instead of the 0-5v wideband (hence wide-band).
The innvoate has a control box which the 0-5v sensor inputs to giving an AFR/Lambda display, it also has a narrowband output FROM THE CONTROL BOX which can be fed to the ecu.

The most common wideband sensor at the moment is the VW oe. fitment bosch sensor which most wideband display kits seem to be using at the moment (budget kits).

I found the easiest way wasto get a thread welded into my decat pipe, it may sound like a PITA but you can run seperate systems then. It only cost me £10 for the thread/bung/welding at hayward and scott.
It is simple to reach to change when i want to remove it also.

Not only does a true wideband sensor give a 0-5v output which wont be nice for the ecu, it needs a constant 0-5v power supply to run it which is only 0.9v on narrowband.

Rob

NISFAN · 25th July 2005, 03:05 PM

Agreed, you could also use something like the Zeitronix unit, which is a wideband display unit (also EGT and boost pressure, +others), and gives narrowband output for the ECU.

check it out
http://www.zeitronix.com/Products/zt2/zt2.htm

D4T · 9th August 2005, 09:02 PM

Sorry, please dont consider this a hijack!

Is that Zeitronix unit meant to good then? i like the look of the product but to be honest, stupid as it may seem, the website puts me off!

Who rates these units then?

Thanks,

D4T

lightspeed · 9th August 2005, 09:19 PM

Wideband is the only way to go.

I built myself a kit from www.wbo2.com complete with LED dash display.
Website has tons of good info. Well worth a look.

It uses the bosch VW sensor. It works superbly and is easy to read at a glance.
Also has built in datalogging or for extra memory can log to a laptop.
Costs less than some of the narrow band junk.

22nd July 2005, 11:51 PM	#1 (permalink)
Josewick GTR Register Member Join Date: May 2002 Location: Milton Keynes Posts: 692	AFR / Lambda Sensor Question I am thinking about havin a AFR gauge or some sort for my car.. But looking at some others, they flick so quickly that you cannot read.. Is it the gauge itself or is it the lambda sensor?? My question is, if the std lambda sensor is not accurate, then how can the ECU rely on its info to adjust the fueling..?? I know people will recommand the WIDEBAND sensor, what is the difference an how does it work? Or should I say can I just buy a wideband sensor to replace my existing lambda sensor? Will it work like that?? I know innovate does a good bit of kit.. In fact far too good that its way beyond me... I only want something accurate and simple.. Don't need to record or anything else.. And i don;'t like the idea of having to drill thru the exhaust and adapt another sensor to it.. Something just replacing the existing one is perfect.. Thanks

25th July 2005, 08:35 AM	#4 (permalink)
tweenierob GTROC Member Join Date: Aug 2003 Location: herts Posts: 1,833	Right..... The std ecu uses the narrowband std lambda readings for vacumn fuelling assistance, the maf sensor(s) give the ecu an airflow reading and the ecu adds fuel according to the airflow but on vacumn the lambda helps the ecu find the optimum afr (stoich). Vacumn is usually on cruise and any off boost running. When the air pressure reaches over atmospheric (zero on boost gauge) the lambda has no bearing on fuelling. Basically on vacumn the lambda is closed loop assisting the afr and on boost the lambda is open loop, no assist. Narrowband sensors generally read 0-1v whereas wideband sensors generally read 0-5v. Narrowband sensors overheat on boost, which is i believe the main reason they have no impact on - on boost fuelling, plus the narrow voltage scale doesnt help. Ideally you want to run the std lambda for the ecu but use wideband for display purposes, a std ecu will not support wideband directly. A wideband system like the innovate one is ideal, it can display true wideband readings but also output a narrowband signal to input to your ecu. just woken up so i am sure i will add more later but the above might help you understand it a bit clearer. If narrowban shows lean but EGT is not high, i would suspect the narrowband sensor has overheated. Rob __________________ 599hp R35 Gtr www.trracing.co.uk T62 Going back on for track WTF!! :D Addicted to Snett!! Roll on the 24th of jan £99 rocks!

25th July 2005, 12:39 PM	#6 (permalink)
tweenierob GTROC Member Join Date: Aug 2003 Location: herts Posts: 1,833	I think maybe you are confusing the sensors... There are different bosch sensors, if i remember rightly from my GTIR days there is a bosch sensor that reads 0-1v and doesnt overheat much. This also has a nissan plug on it but is not true wideband, i am assuming that it is known as a wideband sensor as it doesnt overheat and will read high temp AFR's still but on a 0-1v scale instead of the 0-5v wideband (hence wide-band). The innvoate has a control box which the 0-5v sensor inputs to giving an AFR/Lambda display, it also has a narrowband output FROM THE CONTROL BOX which can be fed to the ecu. The most common wideband sensor at the moment is the VW oe. fitment bosch sensor which most wideband display kits seem to be using at the moment (budget kits). I found the easiest way wasto get a thread welded into my decat pipe, it may sound like a PITA but you can run seperate systems then. It only cost me £10 for the thread/bung/welding at hayward and scott. It is simple to reach to change when i want to remove it also. Not only does a true wideband sensor give a 0-5v output which wont be nice for the ecu, it needs a constant 0-5v power supply to run it which is only 0.9v on narrowband. Rob __________________ 599hp R35 Gtr www.trracing.co.uk T62 Going back on for track WTF!! :D Addicted to Snett!! Roll on the 24th of jan £99 rocks!

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23rd July 2005, 02:31 AM	#2 (permalink)
Eagle Eyes GTR Register Member Join Date: Aug 2002 Location: London Posts: 725	In my opnion, fitting an EGT gauge is better than fitting an AFR gauge. Much easier to monitor. I may be wrong on this but with lambda sensor, it has a tendency of getting clogged/covered with carbon as a result of prolonged slow driving. You'll then get inaccurate readings. This is what i find on my AFR gauge. Although AFR gauge is showing lean, my EGT gauge is showing constant reading so can't be running lean.

24th July 2005, 09:48 PM	#3 (permalink)
Josewick GTR Register Member Join Date: May 2002 Location: Milton Keynes Posts: 692	problem is... with exhaust temp.. its different from car to car.. wwhere AFR gauge / meter, i know if its about 14 then its about right... So.. my question is.... can I replace my existing Lambda sensor with a WIDEBAND one (from bosch) and link that up with the poxy AFR gauge and get an accurate reading??

25th July 2005, 09:57 AM	#5 (permalink)
Josewick GTR Register Member Join Date: May 2002 Location: Milton Keynes Posts: 692	Thanks Rob.. you are a star.. OK.....what I am trying to avoid is to get one that I have to muck about drilling a fitting onto the downpipe then blank it off after use.. So .. if..... I can use a bosch wideband one (hopefully the plugs are the same).. I can just use that with an aftermarket AFR gauge to get a good reading.. But the concern now is.. if they have different voltage output, the range is different and the ECU will not work with it too well.. When you say Innovate uses a wideband that has narrowband output and can display a wideband signal.. Is it their control box that does the convertion or the sensor itself.? COs i remember reading their product details, they also use the bosch wideband sensor..?? Thanks

25th July 2005, 03:05 PM	#7 (permalink)
NISFAN GTR Register Member Join Date: Oct 2003 Location: Herts Posts: 1,696	Agreed, you could also use something like the Zeitronix unit, which is a wideband display unit (also EGT and boost pressure, +others), and gives narrowband output for the ECU. check it out http://www.zeitronix.com/Products/zt2/zt2.htm

9th August 2005, 09:02 PM	#8 (permalink)
D4T GTR Register Member Join Date: Jun 2004 Location: Sussex Posts: 427	Sorry, please dont consider this a hijack! Is that Zeitronix unit meant to good then? i like the look of the product but to be honest, stupid as it may seem, the website puts me off! Who rates these units then? Thanks, D4T

9th August 2005, 09:19 PM	#9 (permalink)
lightspeed GTROC Member Join Date: Jul 2002 Location: South-west Posts: 1,812	Wideband is the only way to go. I built myself a kit from www.wbo2.com complete with LED dash display. Website has tons of good info. Well worth a look. It uses the bosch VW sensor. It works superbly and is easy to read at a glance. Also has built in datalogging or for extra memory can log to a laptop. Costs less than some of the narrow band junk.