Lambda sensors

My 1996 4.6 P38 passed it's MOT today - but only just !
Garage reckons the lambda sensors are on the way out as it struggled through parts of the emissions test
I had thought that I was using slightly more fuel than usual but put that down to driving style
Anyone know of a mail order supplier of sensors and how much they cost please ?

This is NOT the way to fix your car - what you need to do is to find out if the oxygen sensors are capable of working,then find outwhat is stopping the injection and ignition system from working properly if they are OK.If your car runs LPG aswell then it may just need an ECU reset and a few tweaks.
There could be loads of things causing your issue - many of them can be fixed without new parts,what you need is someone to check it over.Set up properly the emissions test is easily passed - your car cant be far off as it does not take much for it to be a mile off passing.

Almost sounds to me like a bit of dodgy garage touting for business. "The car has passed but you could give it to us, spend a load of money for something you don't actually need". I agree with eightinavee, find a reputable independant who can check it out properly.

Dorset VogueSE said:

Almost sounds to me like a bit of dodgy garage touting for business. "The car has passed but you could give it to us, spend a load of money for something you don't actually need". I agree with eightinavee, find a reputable independant who can check it out properly.

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Happily this is not the case - the garage I use is owned by a mate who I have known from primary school, and my son works in the paint shop too
He doesn't have any of the diagnostic tools for rangies though as he is not a land rover specialist
If I book a diagnostic session in Glasgow (there is an independant specialist there ) will this show up what the likely cause is then ?

eightinavee - I don't have lpg installed, and I agree there can't be too much wrong as it is running fine - I suppose hooking it up to testbook or whatever is the way to go rather than just buying bits at this stage
Thanks for the advice guys

Just another question about Lambda sensors .....

Just had mine on the test rig at my local landy Dealer and got a fault code P1158 ....Oxygen sensor problem with switching lean, sensor for bank B (driving cycle C)

They told me it was a Lambda sensor problem and Ive ordered one from a dealer down south (half the price I was quoted at my dealer).

Just now I "googled" P1158 and came up with the same fault description but for the sensor below the cat ..... (P1152 being the fault code for the one above).
Now Im confused ...... can anyone tell me if there are in fact 4 sensors, one each side above the cat, and one each side below ...... or have I got this all terribly wrong ..... lol

jh

........... just read a comment on another site that UK rangies do not have the second sensor below the cat ...... is that true ...??

Uk spec cars only have upstream sensors,(precat) and p1158 is just a bank B code,drivers side,rhd.It wont be a duff sensor as their natural output state is 5v.(Lean) So when running it must have already switched down to rich - 0v, so you need to look for reasons for the sensor to stay switched down rich.This could be a slight misfire,dodgy plug/lead/coil,failed fuel pressure reg or leaky injectors,(unlikely)

Teamemmenracing said:

........... just read a comment on another site that UK rangies do not have the second sensor below the cat ...... is that true ...??

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Another site???????????

eightinavee said:

Uk spec cars only have upstream sensors,(precat) and p1158 is just a bank B code,drivers side,rhd.It wont be a duff sensor as their natural output state is 5v.(Lean) So when running it must have already switched down to rich - 0v, so you need to look for reasons for the sensor to stay switched down rich.This could be a slight misfire,dodgy plug/lead/coil,failed fuel pressure reg or leaky injectors,(unlikely)

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Thanks for the info ...... helps a lot . ..... mmmmmmm have already paid for a new sensor and its in the post so I guess I'll change that anyway.

It runs a little lumpy at idle but pulls clean all the way through the rev range and doesn't missfire under load, plugs were changed a couple of months ago, Id expect plugs/leads/coils to break down under load but Ive been wrong before.

Its a 1998 4.6 HSE btw ... thanks again .....
Just for the record they charged me 88 quid to plug it in and tell me that, took 20 mins lol.

jh

Sirus said:

Another site???????????

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God I know, how bad am I ...............
Must admit tho, since I bought the beast Ive spent most of my awake time online looking for ways to keep it happy ...... nothing really special, just the usual, new block (slipped liner), EAS ... etc etc .... lolol

Its a 4.6 HSE 1998 btw .......

Coil springs going on in a few weeks ..... I know its sinful but Ive been riding around for a year now with a manual air set up ..... set "high" and I kinda like it ..... got fed up arguing with the EAS .....
Found a set at Brookwells for 350 plus change which is about the price of a valve block lololol.

Wouldnt drive anything else ........ lol,

jh

Good news for once .....

changed the lambda sensor on the B side ...... and it sailed thru the emissions test
and ...... fuel consupmtion is about 30% better ...... result

I have a lumpy idle, put the Testbook on it a week ago, cleared down the faults and re-set the adaptive on the ECU, just tested again and got:

P1158, OXYGEN SENSOR PROBLEM WITH SWITCHING LEAN SENSORS (BANK B)
P1138, OXYGEN SENSOR PROBLEM WITH SWITCHING LEAN SENSORS (BANK A)

I doubt that both Lambda sensors go at the same time, therefore could it be something else. P38 4.6 HSE Gems running on gas.

I've had both Lambda sensors go west before, they don't last forever, and once both replaced the fault codes didn't return.

magictiny said:

I have a lumpy idle, put the Testbook on it a week ago, cleared down the faults and re-set the adaptive on the ECU, just tested again and got:

P1158, OXYGEN SENSOR PROBLEM WITH SWITCHING LEAN SENSORS (BANK B)
P1138, OXYGEN SENSOR PROBLEM WITH SWITCHING LEAN SENSORS (BANK A)

I doubt that both Lambda sensors go at the same time, therefore could it be something else. P38 4.6 HSE Gems running on gas.

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It is something else,the natural output for your sensors is 5v - a lean signal.So if they are not switching back up from 0v,(Rich) then it is simply running too rich and the short term fuel trims cant get it down lean enough.Most likely your LPG system.

eightinavee said:

It is something else,the natural output for your sensors is 5v - a lean signal.So if they are not switching back up from 0v,(Rich) then it is simply running too rich and the short term fuel trims cant get it down lean enough.Most likely your LPG system.

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I think you might have the answer there eight, I will take her back to my gas mechanic and see what he can do, between his laptop and my testbook, we should be able to figure it out...

Got it figured out, not Lambda sensors at all.

Misfiring on one pot, new HT leads and she is a goodun. £25 - cheap as chips.

Service life of the cats and lambda sensor was 96,000 miles.
The very last of the p38a did have pre and post lambda sensors only as they had no uk spec Thor ecus fitted.

vougese39 said:

Service life of the cats and lambda sensor was 96,000 miles.
The very last of the p38a did have pre and post lambda sensors only as they had no uk spec Thor ecus fitted.

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No, the service life was alot longer if the car ran well - 96,000m was when LR thought they could stiff the owner for a load of cash....