Lambda sensor probelm

Tony
Enlisted
Posts: 5
Joined: Thu Sep 23, 2010 12:14 pm
Contact:

Lambda sensor probelm

Postby Tony » Mon Sep 27, 2010 1:29 pm

Howzit Gents !
I got a golf 4 Cabrio 2.0 longblock.
I went to my Mac and he advised that my Lambda sensor was gone.
What are the symtoms of a blown lambda sensor?

Car does have a branch with a 57mm freeflow, could that affect the Lambda sensor?
:bang:

User avatar
Torker
General
Posts: 9556
Joined: Sun Mar 19, 2006 12:21 pm
Car Make: VW
Car Model: Golf GT
Membership No: 1464
Location: Springs

Re: Lambda sensor probelm

Postby Torker » Mon Sep 27, 2010 1:58 pm

Tony wrote:Howzit Gents !
I got a golf 4 Cabrio 2.0 longblock.
I went to my Mac and he advised that my Lambda sensor was gone.
What are the symtoms of a blown lambda sensor?

Car does have a branch with a 57mm freeflow, could that affect the Lambda sensor?
:bang:


Gone - as in not refitted when the branch and exhaust was done or just faulty? I'm not too clued up on Lambda's but I doubt the exhaust mods can cause it to go faulty, more than likely the poor quality of our fuel.
Current rides:

VW Golf - 83 GT 2.1 16V 2-door with throttles
VW Golf - 78 LS 2.0 8V 4-door (2.1 ABF with throttles in progress)
VW Golf - '08 Citi Storm - 1.4 for now
Hyundai - 1.4 Getz (daily)

User avatar
Jetta2
Field Marshal
Posts: 13657
Joined: Sun Dec 10, 2006 12:32 am
Car Make: VW, VW, Aprilia
Car Model: Mk2, Mk3, Aprilia Tuono V4
Membership No: 1087
Location: Menlo Park, Pretoria
Contact:

Re: Lambda sensor probelm

Postby Jetta2 » Mon Sep 27, 2010 2:08 pm

Did your mechanic do a scan using VAG-COM and confirm it is the Lambda sensor?
1989 Mk2 Jetta 2.0 8V-T
1996 Mk3 Golf VR6
2013 Aprilia Tuono V4 APRC

Tony
Enlisted
Posts: 5
Joined: Thu Sep 23, 2010 12:14 pm
Contact:

Re: Lambda sensor probelm

Postby Tony » Mon Sep 27, 2010 3:53 pm

Jetta2 wrote:Did your mechanic do a scan using VAG-COM and confirm it is the Lambda sensor?


yes when he ran the dignostic on the car.

My idle fluctuates when she is stationary!

User avatar
Rietbok
Cadet
Posts: 214
Joined: Mon Apr 24, 2006 3:39 pm
Car Make: VW
Car Model: Vivo
Membership No: missing
Location: East London
Contact:

Re: Lambda sensor probelm

Postby Rietbok » Mon Sep 27, 2010 5:11 pm

And just to be clear, the Lamda sensor is still there? ( not removed when they did the exhaust as suggested above? )

Very basically the Lamda sensor tells the ECU if all the fuel is being burnt, ( too rich, too lean or just right ). But the ECU should default to some "safe" but not wonderful value if the Lamba sensor fails.

Symtoms... I've not had a car with bad lamba sensor to play with, so not 100% sure. Any takers?
2011 Polo Vivo Sedan 1.4 Trendline.
Serious VW fan.
Wife's car: 2010 VW Polo Vivo 1.4 base model.

Image

User avatar
panic-mechanic
Panic's Place
Posts: 23230
Joined: Mon Jul 29, 2002 9:08 am
Membership No: 79
Location: Benoni, putfontein.
Contact:

Re: Lambda sensor probelm

Postby panic-mechanic » Mon Sep 27, 2010 7:26 pm

depending on which management but most will simply be slightly rich and the fuel consumption will suffer. Other than that not much to notice.
Stephan van Tonder - Jhb - Putfontein Benoni
'07 Audi S6 V10 - beast !!!!!
'05 Audi A6 3.0L TDI Avant
'07 Audi A4 2l TDI
'95 Audi 90 coupe quattro
'13 VW CC 2l tdi (repair project)
'05 Touareg v10
'90 mk2 jetta 2l 16v

Perfect Power dealer. I do dyno tuning.

User avatar
g60 golf
Moderator
Posts: 3988
Joined: Tue Jul 18, 2006 6:51 pm
Membership No: 388
Location: jhb
Contact:

Re: Lambda sensor probelm

Postby g60 golf » Tue Sep 28, 2010 6:45 am

Be carefull on the cabrio managment.
It was a bit nasty.There could be a nother thing causing the lambda to come up as fualty.
Cam timming and dist timing and then also fuel pressure.Check those items first.
G60 16V GOLF

WHAT WE LEAVE BEHIND IS NOT AS IMPORTANT AS HOW WE LIVED.

IT IS NOT UNSAFE IT IS OLD SCHOOL!!!!!!!!!

ALDO IS THE MAN WITH A GUN.
THATS HOW WE ROLL [SAINT-J]
GTS KNOWS HOW TO MAKE A STICKER.

Tony
Enlisted
Posts: 5
Joined: Thu Sep 23, 2010 12:14 pm
Contact:

Re: Lambda sensor probelm

Postby Tony » Tue Sep 28, 2010 8:24 am

g60 golf wrote:Be carefull on the cabrio managment.
It was a bit nasty.There could be a nother thing causing the lambda to come up as fualty.
Cam timming and dist timing and then also fuel pressure.Check those items first.


I did my cam belt change on friday so the timming was set as well.

Tony
Enlisted
Posts: 5
Joined: Thu Sep 23, 2010 12:14 pm
Contact:

Re: Lambda sensor probelm

Postby Tony » Tue Sep 28, 2010 8:27 am

Rietbok wrote:And just to be clear, the Lamda sensor is still there? ( not removed when they did the exhaust as suggested above? )

Very basically the Lamda sensor tells the ECU if all the fuel is being burnt, ( too rich, too lean or just right ). But the ECU should default to some "safe" but not wonderful value if the Lamba sensor fails.

Symtoms... I've not had a car with bad lamba sensor to play with, so not 100% sure. Any takers?


yes it is still there as the mac checked it there when i did my clutch.

User avatar
Kashi
Cadet
Posts: 56
Joined: Tue Jul 20, 2010 12:17 pm
Car Make: Audi
Car Model: 8P A3 2.0 FSI
Membership No: missing
Contact:

Re: Lambda sensor probelm

Postby Kashi » Tue Sep 28, 2010 9:03 am

Found this on the net. Long read but worth it

Drivability Symptoms

A lambda sensor’s normal life span is 30,000 to 50,000 miles, but the sensor may fail prematurely if it becomes clogged with carbon, or is contaminated by lead from leaded petrol or silicone from an antifreeze leak or from silicone sealer.

As the sensor ages, it becomes sluggish. Eventually it produces an unchanging signal or no signal at all. When this happens, the Check Engine Light may come on, and the engine may experience drivability problems caused by an overly rich fuel condition. Poor fuel economy, elevated CO and HC emissions, poor idle, and/or hesitation during acceleration are typical complaints.

If the average voltage from the lambda sensor is running high (more than 0.50V), it indicates a rich condition, possibly due to a bad MAP, MAF or Air Flow sensor or leaky injector. If the average voltage reading is running low (less than 0.45V), the mixture is running lean possibly due to a vacuum leak or because the sensor itself is bad.

If the lambda sensor continually reads high (rich), it will cause the engine computer to lean out the fuel mixture in an attempt to compensate for the rich reading. This can cause lean misfire, hesitation, stumbling, poor idle and high hydrocarbon emissions (from misfiring).

If the lambda sensor continually reads low (lean), it will cause the engine computer to enrich the fuel mixture. Injector pulse width will increase causing fuel consumption and carbon monoxide emissions to go up. Constant rich fuel mixture can also cause the catalytic converter to overheat and it may be damaged.

If the lambda sensor’s output is sluggish and does not change (low cross counts & long transition times), the engine computer will not be able to maintain a properly balanced fuel mixture. The engine may run too rich or too lean, depending on the operating conditions. This, in turn, may cause drivability problems such as misfiring, surging, poor idle, and high emissions.

If a heated sensor has a faulty heating circuit or element, the sensor can cool off at idle causing the system to go into open loop. This usually results in a fixed, rich fuel mixture that will increase emissions.

Sometimes an apparent lambda sensor problem is not really a faulty sensor. An air leak in the intake or exhaust manifold or even a fouled spark plug, for example, will cause the lambda sensor to give a false lean indication. The sensor reacts only to the presence or absence of oxygen in the exhaust. It has no way of knowing where the extra oxygen came from. So keep that in mind when diagnosing oxygen sensor problems.

The lambda sensor is also grounded through the exhaust manifold. If rust and corrosion of the manifold gaskets and bolts is creating resistance, it may affect the sensor's output. To rule out a bad ground, use a digital volt meter to check for a voltage drop between the sensor shell and the engine block. More than 0.1v can cause a problem.

Lambda Sensor Checks

A good lambda sensor should produce a fluctuating signal that changes quickly in response to changes in the oxygen level in the exhaust. The best way to check the sensor is to observe the sensor’s output on a waveform scope or oscilloscope. A scope will display not only the sensor’s minimum and maximum voltage readings, and average voltage reading, but also its back and forth voltage oscillations from rich to lean.

Sensor output can also be read directly with a 10K ohm impedance digital voltmeter, or some code readers.

CAUTION! Never use an ohmmeter on a zirconium O2 sensor in an attempt to check the sensor because doing so can damage it. And never jump or ground the sensor’s leads.

The lambda sensor’s voltage reading should have a minimum reading of 200 millivolts (0.20 V) and a maximum reading of 800 millivolts (0.80 V). If the sensor reading is averaging low (under 400 millivolts) or high (over 500 millivolts), the engine may be running rich or lean because of some other problem.

If the sensor’s output voltage never gets higher than 0.60 V and never drops to less than 0.30 V, it needs to be replaced. The same is true if the sensor’s output is sluggish or doesn't change.

To check the sensor’s response to changing oxygen levels in the exhaust, first create an artificially lean condition by pulling a large vacuum line. When extra air is introduced into the engine, the sensor’s voltage output should drop to 0.2 V.

To check the sensor’s rich response artificially enrich the mixture by, if possible, clamping the return fuel line momentarily. This will force more fuel through the injectors and should cause the O2 sensor’s voltage to increase to 0.8 V.

If the sensor’s output fails to respond to the changes you've created in the oxygen level in the exhaust, it’s time for a new sensor.

Zirconia sensors can also be bench-tested by heating the tip with a propane torch while monitoring the sensor’s voltage output with a digital voltmeter. Connect the positive voltmeter lead to the signal wire (normally black) coming out of the O2 sensor and the negative voltmeter lead to the sensor’s outer shell. Then heat the tip of the sensor with the propane torch. The tip should be hot enough to turn cherry red, and the flame must enter the opening into the sensor tip. If you get a voltmeter reading above 600 millivolts (0.6 volts), and the reading quickly changes as you move the flame back and forth over the tip, the sensor is okay. A low reading or one that is slow to change means the sensor needs to be replaced.

Removing Lambda Sensors

Removing the sensor when the engine is cold will lessen the odds of stripping the threads in the exhaust manifold. Penetrating oil may be needed to loosen rusted threads. Once the sensor has been removed, the threads in the manifold should be cleaned before the new sensor is installed. Apply graphite grease to the sensor threads unless the threads are precoated.

Replacing Lambda Sensors

Everybody knows that spark plugs have to be replaced periodically to maintain peak engine performance, but many people don’t realise the same goes for oxygen sensors. As long the lambda sensor is working properly, there’s no reason to replace it. But after 30,000 to 50,000 miles of being constantly bathed in hot exhaust gas, a build up of deposits on the sensor tip can make it sluggish. If there’s enough clinker on the sensor tip, the sensor may produce little or no voltage at all. This produces a false "lean" signal that makes the computer think the engine needs more fuel, which it doesn’t but gets anyway. This creates a rich fuel condition that kills fuel economy and sends carbon monoxide and hydrocarbon emissions soaring. The engine may also experience additional drivability problems such as surging or hesitation.

The same kind of thing can happen if the lambda sensor is contaminated by deposits from sources other than normal combustion. It only takes a couple of tanks full of leaded petrol to ruin a lambda sensor (and catalytic converter). A lead-contaminated oxygen sensor will typically have light rust coloured deposits on the tip. Another source of sensor contamination can come from silicone poisoning. If somebody used the wrong kind of silicone sealer to seal up a leaky rocker box cover or manifold gasket, silicone can find its way into the engine and foul the sensor. Silicates, which are used as corrosion inhibitors in antifreeze, can also cause the same kind of poisoning. Sources here might include a leaky head gasket or cracks in the combustion chamber. Silicone deposits on the sensor tip will have a shiny white to grainy light gray appearance.

If the engine has an oil consumption problem due to worn valve stem seals, piston rings and/or cylinders, a build up of heavy black to dark brown oily deposits on the sensor tip can make it sluggish. If the deposits have a black powdery consistency, the fuel mixture is running rich. This may be due to the sensor already having failed, or it might be due to something else such as a leaky injector or a computer problem, or constant short journeys where the cold start system doesn’t have time to come off (open loop) known as housewives’ car.

Whenever you suspect a lambda sensor problem, the first thing you should do is scan for any codes that would implicate the sensor circuit. A code by itself doesn't necessarily mean the sensor is bad, however. It might be a wiring problem or something else. So always follow through with the diagnostic check to diagnose what’s wrong before you replace anything.

If you don’t find any codes, that doesn’t necessarily mean the lambda sensor is okay. In many instances, a sluggish sensor may not be bad enough to record a fault code but will still be causing an emissions or drivability problem.
The best car safety device is a rearview mirror with a cop in it!!!

User avatar
g60 golf
Moderator
Posts: 3988
Joined: Tue Jul 18, 2006 6:51 pm
Membership No: 388
Location: jhb
Contact:

Re: Lambda sensor probelm

Postby g60 golf » Wed Sep 29, 2010 6:47 am

How did he set timming as the timming on those is static only and dist is locked in place.
One has to get the cambelt on correct with dist on its mark.
Hows the fuel pressures?
Check the wires between lambda and the ecu too to make sure there is no shorts or broken wires.
G60 16V GOLF

WHAT WE LEAVE BEHIND IS NOT AS IMPORTANT AS HOW WE LIVED.

IT IS NOT UNSAFE IT IS OLD SCHOOL!!!!!!!!!

ALDO IS THE MAN WITH A GUN.
THATS HOW WE ROLL [SAINT-J]
GTS KNOWS HOW TO MAKE A STICKER.

Return to “General Tech Discussions”

Who is online

Users browsing this forum: Momo_cassim, panic-mechanic and 90 guests