Problem with the car!

[Tommy_G]

started today, started accelerating juddery,

i checked the plugs they all work, also the exsaust is on tight....it sort of pops every couple of seconds. sort of sounds like a scooby.

noise seems to be comming from the exhaust area, but its brand new!

Any ideas?

cheers Tom

[oli_h]

lambda sensor or maybe your cat sounds a bit like the problems i was having, is it a bit delayed when putting your foot down

[Glanza_Ragger]

yepp as oli said, if its not your spark plugs etc, check your lambda sensor. sounds like that has gone. can you do an ecu check?

[Tommy_G]

wat does the lambda sensor do? when i put my foot down it just doesnt go...goes to 40ish, wont accelerate.

how do you check the lambda and how do i do an ecu check? guess i need some equipment

[Tommy_G]

seems all the time.. whats the reason it could be misfireing for....i did clean the rocker cover the other day but, it ran fine after

[Tommy_G]

ok cheers mate ill have a proper look 2moz

[woody]

did you change your wheels recently because that could explain the juddering

[Bourkey]

it could be that dodgy petrol thats been handed out at a few petrol stations.thousands of people are have exactly the same problems due to dodgy petrol.

[Mikey Jay]

Was gonna suggest what Bourkey just said.

Been to Tescos or Morrisons for petrol lately?

(as was the South East that had most of the dodgy petrol)

[prangers]

i had the same problem before my engine blew

id check for water in the oil and water in the plugs

mine was the head gasket. i carried on driving it for a while with the misfire but thought it was just a dodgy bit of water in the injector connector from where id washed the engine bay..... it wasnt and required a new engine

hope that helps

[Tommy_G]

hope mine isnt as drastic as your pranger, but i did forget i had "degunked" the rocker cover and i checked the plugs today, and two were wet nd smelt of petrol...also the smell of the gunk cleanin stuff.

cleaned them up and its running fine now..touch wood,... i am going to get new leads and plugs anyway as they look old to be honest. and may also get it serviced properly.

[Glanza_Ragger]

a faulty lambda sensor would make it missfire, and judder extremely. and then it would chuck the eml on.

run some redex through it too

[paul w]

Mine was similar to this and it was just one of the leads had given up the ghost,new leads no problems.

[Tommy_G]

new leads... shouldnt cst to much should they? typed them in on egay nd came up with some racin ones for £72!

[paul w]

I got mine off ebay for £35,i just sold a set of magnacores 2 weeks ago or you coulda had them.Get hold of some standard leads to try them if it solves the problem then get some uprated ones.

[Glanza_Ragger]

thanks to a website.

The exhaust gas oxygen sensor (EGO or O2), or lambda sensor, is the key sensor in the engine fuel control feedback loop. The computer uses the O2 sensor's input to balance the fuel mixture, leaning the mixture when the sensor reads rich and richening the mixture when the sensor reads lean.

Lambda sensors produces a voltage signal that recognises the amount of unburned oxygen in the exhaust. An oxygen sensor is essentially a battery that generates its own voltage. When hot (at least 250 degrees c.), the zirconium dioxide element in the sensor's tip produces a voltage that varies according to the amount of oxygen in the exhaust compared to the ambient oxygen level in the outside air. The greater the difference, the higher the sensor's output voltage.

Sensor output ranges from 0.2 Volts (lean) to 0.8 Volts (rich). A perfectly balanced or "stoichiometric" fuel mixture of 14.7 parts of air to 1 part of fuel gives an average reading of around 0.45 Volts.

The lambda sensor's output voltage doesn't remain constant, however. It flip-flops back and forth from rich to lean. Every time the voltage reverses itself and goes from high to low or vice versa, it's called a "cross count." A good O2 sensor on a injection system should fluctuate from rich to lean about 1 per second. If the number of cross counts is lower than this, it tells you the O2 sensor is getting sluggish and needs to be replaced.

Most lambda sensors will cycle from rich to lean in about 50 to 100 milliseconds, and from lean to rich in 75 to 150 milliseconds. This is referred to as the "transition" time. If the O2 sensor is taking significantly longer to reverse readings, this too is an indication that it is getting sluggish and may need to be replaced.

Observing the sensor's waveform on a scope is a good way to see whether or not it is slowing down with age. If the sensor becomes sluggish, it can create hesitation problems during sudden acceleration.

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 richen 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.

[oli_h]

my lambda had gone had the problems tommy was talking about but my eml didnt come on it was juddery and felt like a misfire

[oli_h]

got it in one, thats exactly how my car was, i did have my water pump changed and that may have caused mine to go

[Glanza_Ragger]

lambda as oli's problem was. OR many other things. but dont rule the sneeky little lambda out lurking , hiding waiting to spring a problem on yo ass!

[oli_h]

lol

[white-gt]

[TurboTobz]

2008 why wpukd you bump that