Lambda Sensor issue

[960kg]

Originally Posted by chomerly

Well having hooked up my device I am now getting,

P0141 O2 Sensor Heater Circuit
P0135 O2 Sensor Heater Circuit

On both sensors.
This leads me to believe that the sensors are perhaps ok and the issue may lie elsewhere.

Before replacing the sensors I was receiving a low voltage message too.

Excuse me for perhaps being dumb but if you are saying you get these two error codes up when read by your device then this is what the problem is.

As i said earlier you have put two cheap inferior O2 sensors in and you can`t do that if you want T4 performance.

Everyone on here seems to do it as it`s the cheapest way out but you will find that you can`t send them back as they are now used and you will still have to pay more for the proper part, it is always a silly move.

You can get cheaper that the Volvo Dealer but you are taking chances all the time. Some parts places even give the same number but they are inferior and will not work correctly.

If you are a perfectionist and want the car operating 100% then just bite the bullet, you have already spent a load of dosh so why waste the efforts.

[T4Rick]

Where did you get your sensors from?and there isnt a chance you could have damaged them when installing them?.i bought mine from unipart on my first T4 and i never had an issue with them,a few other members have even bought sensors from other sources and they have been good.

[chomerly]

I got the post CAT one from a salvage yard. The Pre-CAT was purchased as new from eBay.

Both worked fine for a time but after around half an hour the Lambda warning light came on.
In fact, this morning after getting back from work, i reset the error codes using my OBD2 device and the light stayed off.
I had been out to get some fuel as the missus said she needed to go out for a few hours, but that was called off last minute, and then i took my son to college for his enrolment day and on the way back the light came back on.
This was after a longer period of driving this time.
Roughly an hour.

One thing i should mention is that when the lambda lights are on, i get some light smoke coming from the exhaust.
When they are working, or at least appearing to be working, i get no smoke.
Also, i checked the oil today and it was way, way low on the dipstick.
So low that i'm surprised the oil warning light didn't flash up at some stage, but i know that is age specific vehicles with sensors to detect that kind of thing.

Now this had worried me further as i'm beginning to think valve seals or piston rings. But it doesn't explain why it only seems apparent when the lambda sensors are playing up.

[chomerly]

Originally Posted by 960kg

Excuse me for perhaps being dumb but if you are saying you get these two error codes up when read by your device then this is what the problem is.

As i said earlier you have put two cheap inferior O2 sensors in and you can`t do that if you want T4 performance.

Everyone on here seems to do it as it`s the cheapest way out but you will find that you can`t send them back as they are now used and you will still have to pay more for the proper part, it is always a silly move.

You can get cheaper that the Volvo Dealer but you are taking chances all the time. Some parts places even give the same number but they are inferior and will not work correctly.

If you are a perfectionist and want the car operating 100% then just bite the bullet, you have already spent a load of dosh so why waste the efforts.

I get where you are coming from 960 but i'm in the situation now where i still have to source a turbo and possibly a CAT assuming it is contaminated.

And there may be other possible developments which i have described below.

Originally Posted by T4Rick

Where did you get your sensors from?and there isnt a chance you could have damaged them when installing them?.i bought mine from unipart on my first T4 and i never had an issue with them,a few other members have even bought sensors from other sources and they have been good.

I got the post CAT one from a salvage yard. The Pre-CAT was purchased as new from eBay.

Both worked fine for a time but after around half an hour the Lambda warning light came on.
In fact, this morning after getting back from work, i reset the error codes using my OBD2 device and the light stayed off.
I had been out to get some fuel as the missus said she needed to go out for a few hours, but that was called off last minute, and then i took my son to college for his enrolment day and on the way back the light came back on.
This was after a longer period of driving this time.
Roughly an hour.

One thing i should mention is that when the lambda lights are on, i get some light smoke coming from the exhaust.
When they are working, or at least appearing to be working, i get no smoke.
Also, i checked the oil today and it was way, way low on the dipstick.
So low that i'm surprised the oil warning light didn't flash up at some stage, but i know that is age specific vehicles with sensors to detect that kind of thing.

Now this had worried me further as i'm beginning to think valve seals or piston rings. But it doesn't explain why it only seems apparent when the lambda sensors are playing up.

I'm in a catch 22 situation now.
IF the piston rings or valve seals are at fault then i could end up with a monster bill to get it sorted.
This then puts me in a position of whether i can justify the costs of repairing the car or whether to try and by a less problematic one.

[T4Rick]

How do you no the one from the scrap isnt knackered?that maybe knocking the other sensor out.i would have at least gone unipart.i wouldnt touch lambda sensors off ebay

[chomerly]

The lambda sensor is a new NTK part which is why i bought it.

The seller purchased the lambda for his own vehicle but had sold it before getting around to fitting the part prior to putting it on eBay.

The voltages for each part seem fine apart from when i put on my replacement MAF and the voltages dropped and fluctuated like mad.
When i put my original back on though the voltages stay at 1.000 for sensor 1 and 0.960 - 0.965 for sensor 2.

[T4Rick]

So he says mate.Me personaly i would have like to see the car with the light off on the clocks before i bought anything.What did you pay for it?

[T4Rick]

Also when i sold mine on i give the new owner the reciepts as proof

[mitchyboy01]

Originally Posted by chomerly

The lambda sensor is a new NTK part which is why i bought it.

The seller purchased the lambda for his own vehicle but had sold it before getting around to fitting the part prior to putting it on eBay.

The voltages for each part seem fine apart from when i put on my replacement MAF and the voltages dropped and fluctuated like mad.
When i put my original back on though the voltages stay at 1.000 for sensor 1 and 0.960 - 0.965 for sensor 2.

Ntk are good to go they are the O2 sensor division of ngk if I'm not mistaken. They supply lambdas to Volkswagen and other manufacturers as oe equipment That's what I use on my T4 with no probs.

The rear lambda sensors job is only to ensure the cat is working. It basically compares it's reading to the front sensor to make sure there is a difference. My car is a decat so I have a spacer to put the rear sensor away from the exhaust gasses enough not to throw a code.

Also before you get carried away and sell the car, do a compression test, I doubt your rings are fecked. The low oil is probably due to your previous turbo leaking past the seals. I'm sure when I had a lambda code it didn't mention heater circuit.

The heater circuit is only used in cold start anyway. Obviously after a minute or two when The gases heat it up it should function fine, as long as it's only the heater at fault. Does the car idle ok and run smooth at part throttle?

[chomerly]

Originally Posted by T4Rick

So he says mate.Me personaly i would have like to see the car with the light off on the clocks before i bought anything.What did you pay for it?

£35 when i caught the bid.
It was in its last stages of the auction at the time so i though what the hell.

Originally Posted by mitchyboy01

Ntk are good to go they are the O2 sensor division of ngk if I'm not mistaken. They supply lambdas to Volkswagen and other manufacturers as oe equipment That's what I use on my T4 with no probs.

The rear lambda sensors job is only to ensure the cat is working. It basically compares it's reading to the front sensor to make sure there is a difference. My car is a decat so I have a spacer to put the rear sensor away from the exhaust gasses enough not to throw a code.

Also before you get carried away and sell the car, do a compression test, I doubt your rings are fecked. The low oil is probably due to your previous turbo leaking past the seals. I'm sure when I had a lambda code it didn't mention heater circuit.

The heater circuit is only used in cold start anyway. Obviously after a minute or two when The gases heat it up it should function fine, as long as it's only the heater at fault. Does the car idle ok and run smooth at part throttle?

What i'm having trouble understanding is how the sensors can be throwing up the heater circuit issue after around half an hour to an hour of running the car.
I know that 960's feelings are to buy genuine Volvo parts to replace all that i need to replace but at the minute i cannot financially justify doing that until i can narrow down whether something else is causing these sensors to throw up the heater circuit errors.

I'm going to try and do a compression test tomorrow if i can.
I'm hoping a mate will have one that i can borrow for an hour or so.

After trying to refurb my turbo with a rebuild kit, i changed the engine oil over for whatever crap was in there and bought 5 litres of Magnatec.
I can't remember the exact amount of oil i used but i do remember that i had around a quarter of a litre bottle left after filling.
There is also a very slight oil leak and it always seems to sit at the bottom of the engine where it meets the gearbox.
It is ever so slight as it has only just begun to show little drops hanging from the case in the past 10 days or so and it was jet washed over a week before that.

The other thing i've been thinking of is my turbo. Or at least the lack of a working turbo.
The old sensors looked heavily coked when i removed them so i'm wondering if the lack of a turbo is part of this issue or if it's something else that is more serious.

The car runs fine and idles fairly evenly but every now and again it may drop the revs a touch and for about a second. Nothing major but you can hear the change in the engine tone.
It's a bit like the change you get if you turn the lights on while the engine is running.
It dips ever so slightly and then returns to normal.

-----E2A----
That the car does take a few turns before starting up so i don't know if this could be a fuel regulator issue.

It may be best if i took it into a garage and have them give it the once over to see what needs doing.