Dubai-RS4

Hi

A friends RS4 which I am looking to purchase sometimes fails to start especially when left for 2/3 hours in the summer sunshine of Abu Dhabi where temperatures can reach 40C at this time if year. . The issue seems intermittent as it usually starts. The car was taken to Audi and they replaced the air mass sensor however this has not cured the issue. The battery is also new and from Audi.

I noticed that what the car starts normally, there is a slight sound of electric activity going on toward the rear of the car which can be heard from inside. When the issue occurs, there are no such sounds detected so not too sure what the issue could be. If the car is left for a few minutes it usually starts. Furthermore when the issue occurs, the engine is turning, but just fails to fire up the engine.

The car is booked into Audi for a diagnostic check but can any of you experts shed some light on this issue ? On another forum it was suggested that it is likely to be a minor fuel pump relay issue but trying to understand if it could be something else.

Not had an RS before but need to be careful with buying something which will cause me a world of pain....especially as its has high miles.

Any ideas please ?

Thanks
Sean

Alister

Do you have access to VCDS (aka VAG-COM)?

You might find some fault codes triggered that could help narrow down the problem.

sakimano

this whirring sound (when you open the driver's door) is the fuel pump priming the system...getting ready for action

It is located passenger-rear area, under the back seat and is accessible via a panel under there. If it's bad, or going, replacement isn't too tough.

May want to recommend he install a new fuel filter too. That's the weakest link in the fuelling chain, and it is recommended changed at like 50,000 miles by Audi however changing more frequently makes more sense as they are a performance inhibitor. It's like $50. That's 0.0003 seconds of oil money to you

BADRS4

Actually fuel filter is not recommended to be placed by Audi for life of vehicle....(as with tranny fluid, clutch fluid and some other weird things) I will be replacing my fuel filter around 85k though...in Europe gas is much better so they can last longer without changing..also they change cars much more frequent than we do.