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The reality of owning a car is that even the most reliable vehicle will begin to experience issues with age, as parts begin to fail due to wear and tear. Something that happen more often than we would like is having a car that won’t start. As an Audi owner, the idea of this happening is gut wrenching, but something you will possibly deal with at least once in a lifetime. So, get to the bottom of what you can do when this happens, we got our Audi repair shop pros to chat about some of the things that can cause an Audi not to start.
There are some generic issues that can cause any car not to start and can be a result of anything from a bad battery, to a blown fuse all the way to blocked fuel lines and broken fuel pumps. If your car won’t start, a good idea is to take your car to a professional to troubleshoot these common issues, to eliminate the basics and make finding the reason for your car not starting much easier.
Audi Specific Issues
Some Audi models are known to have certain parts go bad with age, which causes your car not to start. A Lot of these issues aren’t usually something you’d look for, unless you are very experienced with Audis.
Camshaft Position Sensors
To make sure your Audi runs smoothly and doesn’t have timing issues, these cars are fitted with a camshaft position sensor. Unfortunately, this sensor can go bad and will need replacing. The common characteristic of a bad camshaft positioning sensor is an engine that turns over fine but doesn’t start, but after leaving the car off for a few minutes or hours your car starts as if nothing was ever wrong. This continues to happen – your car start fine multiple times until the issue comes back with no warning. V-shaped engines tend to have a camshaft position sensor for each bank of cylinders, and if one goes bad you will probably need to replace both.
Mass Air Flow Sensor
With all modern Audis being electronically fuel injected, the car’s engine management computer uses a mass air flow sensor. Commonly called a MAF sensor, this is used to measure quality and density of the air coming into the engine and calculates the amount of fuel that will need to be injected into each cylinder to have the best economy and performance for the engine.
When the MAF sensor goes bad, the engine management computer gets the wrong information, and injects fuel into the engine that has the wrong air to fuel ratio, and causes the car not to start. A simple way to test if the MAF is the problem is to disconnect the wiring from the MAF, and attempt to start the car. Since the engine management computer is not receiving any information about the air from the MAF, it’ll use a basic engine map. If the engine starts with the MAF disconnected, your Audis MAF may need to be cleaned or replaced.
If your Audi has had its software tuned, and is using a custom map, it is possible that the car was tuned while the MAF was dirty or damaged. We recommend that after the MAF is repaired or clean, that you have your car re-tuned to make sure there are no issues.
The vacuum system on an Audi works hand in hand with the MAF sensor. Most common on the B6 Audi A4 is leaks forming in the car’s exhaust gas recirculation system (EGR), but this can become an issue on other models too. The EGR system’s job is to recirculate unburnt gases from the engine back into the engine’s combustion chamber. These gases are then burned and leads to the engine running cleaner. The EGR system makes use of vacuum hoses to achieve this, and if there’s a crack in a vacuum hose or a poorly fitted hose clamp, these unburnt gasses are able to escape.
Along with the MAF sensor, the EGR system feeds information to the engine management computer. If the amount of gas that has been registered by EGR sensors does not reach the combustion chamber, it messes up the engine management computer’s calculation for the air-fuel ratio. One way to know if your car has gas escaping the EGR system is when your car starts, revs a little high then drops, and the car cuts out. In these cases, vacuum lines, fittings and hose clamps will need to be replaced.
It’s important to remember that if you have not kept up with your regular Audi services, the issues may be more extreme, and require far more expensive repairs, such as an engine rebuild. Other causes may be factors that Audi cannot control, such as worn wires, damaged connections, and bad maintenance.
For all your Audi needs, whether it be maintenance, repair or modification, we at Foreign Affairs Motorsport are here to help.