Mixture

spw

spw

Member
Hi

I have a 1.4 petrol 2002 car and a couple of months back the Engine Management light came on.
I took it to an Audi indipendent in Sheffield who performed a scan and diagnosed a temp sensor failure. I was told me it had been giving a false reading that it was always cold and therefore over compensating with fuel and this had been picked up by fault codes in the oxygen sensor.
The Temp sensor was replaced and apart from the sensor popping out on the motorway dumping most of the coolent, the cars been running fine for about a month.

Problems started again a week after the car annual service when again the engine light came on again. Back at the indipendent, a scan showed several exhaust gas levels faults, though this time I was told it was because the car was running too lean. An air leak in the system was suspected but after 2 hours or removing and replacing pipes and road testing nothing was found.
It was noted that the inlet manifold butterfly was carboned up a little but that wasn't susspected to be the issue.

The fault was cleared and I was sent on my way, wallet lighter.

After another 2weeks, and about 500 miles, the lights back on and the cars headed back to the indipendent.

Any thoughts on what could be at fault ?

I have to say my A2 experince is not proving a happy one with over £1800 spent in servicing and fixes in 2 years of ownership.
 
Cars now booked in for thus. for more diagnosis

Could this be a faulty Lambda sensor ?
 
Do you have anyone near you who can read the error codes for you without charging you - someone who has VAGCOM?

Prime suspect for me for rich/lean running would be the Lambda sensor yes indeed as this is a feedback loop for controlling fuelling. A duff Lambda should come up on VAGCOM. They're straightforward to replace (at least they were on my other Audis!).
 
Hopefully I'll get the codes when they rescan it on thus.

I checked the notes on the last invoice and no codes were given, just that an air leak into the vacuum system was suspected but not found.
 
Last week the error codes were again indicating a lean fuel mixture and some sort of leak of air into the vacuum path was susspected, but no leak could be found, so the faults were cleared and I was sent on my way.

The car seemed to be running ok, but I had noticed over the past month or so a slight of a flat spot when pulling away in first and it not being that responsive when you boot the throttle, which goes along with the air leak theory.

Today the cars back in the garage and they've just rung to tell me they now believe its the exahust manifold NOX sensor that's faulty.
 
Yeah I think I have the same problem, the little yellow service light is on, and when I read it on VAGCOM it says the mixture is too poor. I keep resetting the damned thing, but it comes back on after a few km(~80).. 1.4 Petrol(2001) Please, do let me know if you manage to fix this somehow. Thanks.
 
Well, I switched from 95 petrol to 99 petrol, the 99 is more expensive, but the light is gone, lol.
 
the ongoing saga

2 weeks down the line from the Lambda sensor being replaced at great expense and the engine light is back on again.

The car is booked in at the Garage tomorrow but after £375 spent so far on diagnosis and parts I'm not hopeful they have any idea what the fault is.

From what I've read I still suspect its an air leak somwhere because at low revs the cars power delivery seems lumpy.

Maybe I need to either offload the car or get VAG-COM so I can keep resetting it myself
 
Sorry to hear the fault light has come back - please get yourself to somone who has VAGCOM who isn't going to charge you for the privilage of reading your car's error codes, or at least get the garage to show you the fault codes that are coming off when they read them - it's not "privilaged" material! Can't believe you got charged £375 to replace a lambda though, that is shocking.
 
The £375 is not just the replacement of the sensor.
It all started about 2 and half months ago when the engine light first came on.
That time they diagnosed a rich mixture and said this was a faulty temp sensor, which was replaced at £75.
3 weeks later the light was on again, this time lean mixture. They had the car for a day, checked all the hoses, tightened things, sent me on my way £60 lighter.
2 weeks later, light on again, so back to the garage. This time after 2 days they diagnosed the lambda sensor, £255 for the diagnosis and fitting the sensor.
2 weeks later, light on again so its back in the garage tomorrow.

I tend to drive the same trips, few short town trips in the week and couple of 30min motorway drive at the weekend and its seems pretty consistant at failing around a similar time.

I will endevour to get the fault codes and post them up.

Its getting annoying now as i'm loosing faith in the car. I thought being an Audi the car would prove reliable but it seems like one niggly thing after another in the 2 years I've had it.
 
Car is back from the garage, this time they've had the throttle body off and cleaned the carbon build up off it. They didn't seem too confident that they've found the cause of the problem and again could find no air leak.

The fault code is the same as before 17559/P1151 Bank 1, Long Term fuel trim, range 1 lower limits exceeded.
 
I just hate the engine light.......
It's by far the worst thing on my A2.
I wish I could just disable it!
 
The saga continues.......

No warning lights yet but over the last week since it came back from the garage I've noticed the cars 1.4 petrol engine is quite noisy, strangely more noticable from inside the car. It also seems a little sluggish at times and fuel usage has gone up.

Theres a couple of noises - one a ticking noise which sounds like the tappets.
The cars always been a little tapity on start up but that quietened down once it had been running a while, but this seems to persist.
The second noise is more like a hum and I seems like if you you put your hand over the end of a hoover you get a straining noise.

The last work done was to clean out and decarbon the inlet manifold.

Any ideas on what could be the problem ?

sw
 
......pay the garage to keep clearing the fault log. :mad:

I'm begining to think my A2 must have been build late one fri afternoon as I seem to have what seems to be an unreliable car.
I've just heard back from the garage and the new noises I could hear were actually coming from the water pump, which was slowly destroying its bearings and upsetting the timing.
£300 to fix, including new cambelts - I have to say I'm not a happy A2 owner
Wouldn't have minded, but the cambelts were done oct 06 where I was told it wasn't worth replacing the water pump as it had only done 17000 miles.

I'm sure the water pump wasn't helped that a couple of months ago I had a temperature sensor replaced which popped out on the motorway causing me to run without coolent until I could get to the services.
 
A couple of weeks on from my last post and the A2 has been back in the garage and more information on the engine light issue.

This time the car was in to have the Anti-roll bar replaced which was found to be the cause of a dull banging that had been getting steadly worse while driving around the pot holed and speed bumped to hell streets of downtown Sheffield.

As a matter of course now everytime the car is back in the garage they hook it up to the computer and give it a scan. This week the old favourite of 17559/P1151 Long Term Fuel Rail was there again and now a diffrent code, 17961/P1553 Manifold Pressure Signal Ratio out of range. Interestingly neither had triggered the warning light to come on.
The log was checked a couple of weeks back when they replaced the water pump/cambelts and there were no faults, so these have occured over the past couple of hundred miles.

The garage is suggesting that the it is pointing to the MAP sensor but having already replaced the Temperature and Lambda sensors without any fix, i'm less than convinced.

The car seems to run ok, maybe a little noisily, and theres a bit of a flat spot between 1-2500 revs which makes it difficult to get of the line smoothly, which are the classic symptoms of an air leak somewhere.

I did notice when I picked it up from the garage after the cambelt/water pump the car seemed a little more nippy and the flat spot had all but disapeared. This lasted a few days before it returned back to how it was before.

Anyone got any thoughts on what this could be? Any suggestions welcome as I'm now seriously considering bailing on the car.
Up until the temp sensor was replaced I'd not had any of the engine light issues. Now its coming one roughly every 2-3 weeks/100-150 miles. :(
 
How you doing with this?
My lights started to come on too but fortunetly I have a friend that works at the garage down the road adn I'm getting the same bank lean warning.
When does your light come on, I've noticed mine only seems to do it at really low revs, ie pulling off with no throttle or turning the wheel when stationary which causes the revs to drop below where the car would normally idle..
 
mine's usually coming on after a 45min motorway journey. Makes me think its something like a sticking EGR valve

Eventually gave up on the garage and just bought a cheap code scanner to clear the error code.
 
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