cliffcoggin

I have no idea what a stage 1 cr170 is, but if it is a tuned engine then Steve is right, the revs are too low. Generally the more tuned an engine is, the smaller the power band. Most road cars are designed to deliver power over a wide rev range for maximum flexibility, but if you modify the engine for more more power you sacrifice some of that flexibility.

Get your battery tested before doing anything else. It does not matter if it starts the engine satisfactorily, it can still have an internal fault which can interfere with the car's electronics.

I will not argue the economic or thermodynamic aspects of ethanol addition to petrol, but as a chemist most of my working life I challenge the assertion that ethanol is "extremely corrosive". It that was true it would be undrinkable, and given that ethanol is the active ingredient of all booze I don't see millions of people dying after a couple of drinks. Mankind has been making, pumping and storing ethanol for hundreds of years so there are no insurmountable problems in handling it. No, the fact is that ethanol is a different sort of organic solvent to the octane and related hydrocarbons that comprise petrol, and therefore requires different materials to be used for its storage, pumping, sealing, and injection. It would be easy to design and build a fuel system for ethanol, but our problem arises from trying to run ethanol in existing systems designed for petrol. It is similar to the situation when tetra ethyl lead (the anti knock additive) was eliminated from petrol many years ago. Older cars at the time suffered erosion of the valve seats because they relied on the additive to seal them; newer cars were designed with harder seats and have had no problems ever since. With regard to emissions from alcohol fuelled engines, there will still be some CO2 because alcohol contains carbon, though proportionately less than petrol. As for nitrous and other oxides of nitrogen (NOX) I do not know, because the generation of NOX depends on the combustion temperature and efficiency of the engine; high efficiency engines create more NOX than low efficiency.

It's probably the fob battery, they don't last for ever, and at less than a pound for a new one it should be treated as a cheap way of testing the fob.

Glad to hear it, and thanks for the report.

Please do let us know the outcome.

Ten to one you need a new battery. A defective battery will play havoc with the ECU causing strange faults and false warnings., even though the engine is running and the alternator is putting out a good charge.

To be fair, split gaiters are not in themselves causes for an MOT failure because they do not affect the handling of the car. It is only when the the joints lose their grease and dirt then enters causing wear that a failure is justified. That is the reason most MOT test sites warn of an impending fault by means of an "advisory" notice. The onus is on the owner to heed that warning to avoid an expensive repair bill, new boots being cheaper than new joints.

Gary. Not to gainsay any of Gareth's sage advice, but something to bear in mind with a private purchase is that you have little recourse if some major component proves to be defective; whereas a reputable dealer will either stand by any guarantee or be subject to legal redress. Only you can decide if you are willing to pay higher dealer prices for the sake of that extra confidence in the car. If you are not familiar with assessing second hand cars yourself you would find a competent assessor like the RAC would be very worthwhile.

Peter. Any work done on your car by an Audi garage during its existence will have its history centrally recorded, so it should be possible to find when and by whom the sensor was fitted. If you have had work done to it by a non Audi garage there will be no such record.

Please do let us know the outcome. The information would be invaluable for future reference.

Thinking further on the matter, perhaps speculating further would be a better description, if the problem is outside temperature dependant I would investigate how and where that temperature sensor affects the ECU. I reckon there must be an temperature input to the ECU so that it can compensate for ambient air temp variation, but the details of how that circuit operates are beyond me. I suggest an auto electrical specialist would be the best option at the moment, because I have been distinctly unimpressed by reports I have read on this forum regarding the diagnostic abilities of even Audi main dealers. As I said before, if the computer says no, Audi are stumped.

Adrian. My first thought was the instrument cluster but as you have had that changed I am at a loss to think what else it could be. Did Audi have any suggestions, or did the problem not happen while the car was in their hands? Sadly the reliance on diagnostic computers has eliminated the human brain as a means of tracing car faults.

If the rubber boots were split ten months ago the joints they cover will undoubtedly be ruined by now and have to be renewed. It would have been much cheaper to get them fixed when the problem was first found. To get an idea of that cost, pick up a phone and call a garage.

Tell us the bite point of the clutch. In other words at what pedal height does the clutch start to engage? If it is much less than half way up you have a clutch problem.

You have not mentioned what sort of gearbox it has, but assuming it's a manual transmission the problem is most likely a worn clutch. When was it last changed?

The high pressure section of your brake system is losing pressure when the engine is off. That process is normal and inevitable because no seal is perfect, but I would expect it to take many hours or even days. It is not something I have ever checked. Unless you have a hydraulic brake fluid leak that needs the reservoir to be topped up, or a low pressure warning light, or it takes more than approximately 5 seconds to restore pressure once the engine is running, I don't believe you have anything to worry about.

If the light appeared immediately after the service I suggest you take it back to the garage. They may have simply forgotten to reset the service warning.

How on earth did a stone that size get onto the undertray? Had she been off-roading?

I suggest you complain to the vendor. It may not do any good but you have little other recourse.

Sorry, I can't hear anything like you describe, which leaves me guessing. Turbo air leak? Tyre noise? Slipping belt? Unless somebody comes up with a better idea I suggest you get it professionally checked.

I hear nothing but uniform road noise throughout the whole clip. You'll need to provide a better recording and a better description if we are to help, otherwise random guesses is all we can provide.

The bite point should be approximately half way up the pedal travel. Assuming there is no slack in that pedal motion it's time to get the clutch repaired before you damage the gearbox.

The most likely cause is a worn clutch. Where is the bite point when using it i.e. how far up is the pedal when the clutch engages?

You're welcome, and thanks for responding. Few are courteous enough to do so nowadays. Diesels are heavier and stronger than similarly sized petrol engines. All that extra metal takes longer to cool down.