F25 rough starts 1 once then dies then will crank but not start, what do you think the problem is

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Hello Wesley

Hope everything is well. May i ask if there's enough fuel on the vehicle? 

Relly

Thank you for that information Wesley... give me a bit I'll be listing the possible cause and fix

Below are the cause and parts that may need replacement Wesley

• Bad Idle Air Control Valve
• Severe Vacuum leak
• Anti-Theft Alarm System Issue
• Dirty Or Faulty MAF Sensor
• Ignition Issues
• Fuel Pump leak
• Fuel Injection Sensor Issues
• Engine Control Unit Issues
• Faulty EGR Valve
• Clogged Or Old Fuel Filter

1. Bad Idle Air Control Valve

When your car is idle, the idle air control valve (IAC) regulates the air-fuel mixture. It’s connected to the throttle body — part of the air intake system controlling the air flowing into the engine(in response to your gas pedal input).

The IAC also manages engine load changes when your car isn’t moving, like when you turn on the AC, headlights, or radio.

If the idle air control valve fails, your car’s idle may not be the smoothest, or the vehicle may stall completely.

What can you do about it?

You can clean the idle air control valve and check if it stops the car from dying.

If it doesn’t help, chances are there’s an electrical issue inside the valve preventing it from proper functioning.

In such cases, it’s best to let a mechanic handle it. 
They will replace or repair the wiring. 

2. Severe Vacuum Leak

When there’s a hole in a vehicle’s air intake system behind the mass airflow sensor or MAF sensor, it’s called a vacuum leak.

This leak allows unmetered air (air that flows not via the mass airflow) into the engine, messing up the expected air fuel ratio and causes the vehicle to run lean.

What’s “running lean” mean?
Your engine runs lean if the fuel in your car’s ignition chamber is igniting with too much air or too little fuel. 

Now, your car can run with a minor vacuum leak, but if it’s severe, the air fuel ratio will become too lean, causing an engine stall.

What can you do about it?

You can pop the car’s hood to access the engine bay and check for a ripped or disconnected vacuum line. However, the leaks aren’t always apparent, and you will need a mechanic to help.

They’ll use the smoke test where a mechanic pumps smoke into the intake system to find the exact source of the leak.

3. Anti-Theft Alarm System Issue

An anti-theft system, when active, won’t send any power to the fuel pump. But if you have the right car keys, the anti-theft system should switch off after turning the ignition key to the on position.

But when it doesn’t turn off, the alarm may be triggered or show it’s active on your dashboard. And as a result, the car won’t start.

What can you do about it?

Your anti-theft alarm system should have a key symbol on your dashboard that should turn off a few seconds after starting the car. If it doesn’t, try to lock and then unlock your car to try again.

If it still doesn’t turn off, there could be a problem with your car key or even the alarm. Take your car to a mechanic to find out.

4. Dirty Or Faulty MAF Sensor

A MAF or mass airflow sensor measures the amount of air entering your car’s engine and is quite sensitive.

Any dirt and oil buildup that’s able to go past the engine air filter can easily pollute the sensor.

What happens then?
A dirty MAF sensor may often read incorrect air measurements, which will mess up the air fuel ratio, and your car will die.

What can you do about it?

You can clean the sensor with a dedicated MAF sensor cleaner only to fix the issue. If this doesn’t work, you may have to replace it.

Note: When cleaning, DO NOT touch the mass airflow sensor directly or clean it with other methods. It’s recommended to let the professionals tackle it.

5. Ignition Issues

The ignition system generates the spark to ignite the mixture of air and fuel in the internal combustion chamber.

Now there can be several issues in your ignition system. It can be:

• Faulty spark plug
• Weak car battery
• Corroded battery 
• Faulty ignition switch
• Faulty ignition coil

What can you do about it?

Ensure everything is correctly connected at the battery and check for corrosion on the battery terminals. 

If you detect excessive corrosion, try to clean the terminals with a battery terminal cleaner.

Next, check each spark plug. If the tip or electrode has excessive wear, it’s time for a replacement. You can also look for fuel and oil contamination in your spark plug.

While you’re at it, take a look at the ignition coil as well because a faulty one won’t provide a consistent spark to the plugs.

As far as your ignition switch goes, check the switch contacts for wear and tear.
If you spot any damage, you need a replacement.

6. Fuel Pump Leak

A fuel pump is a simple device that moves fuel from one location to another.

If there’s a fuel pump leak, it’ll create issues for the internal combustion process. The engine always needs the right amount of air-fuel mix for ignition.

A fuel leak or a bad fuel pump won’t let the right amount of fuel travel to the combustion chamber.

What can you do about it?

Most new cars have sensors that detect the problems with the fuel pump or within the fuel system before it develops into something more dangerous. And the car will let you know if this happens via the check engine light.

If the check engine light is on, get your car examined by a mechanic. 
Chances are you have to replace it.

7. Fuel Injection Sensor Issue

The fuel injector is a device that uses a certain amount of pressure to inject the right amount of fuel into the internal combustion chamber. And the engine control unit communicates with the fuel injector via the sensor attached to it.

Now the sensor tracks the amount of pressure in the fuel injector, then transmits this information to the engine control unit. Then, your car modifies the pressure accordingly.

If there’s an issue with this fuel injection system or sensor, your car may die because of insufficient amount of fuel needed for proper combustion.

Another reason for a car engine stall, apart from fuel supply issues, can be a clogged fuel injector.

What can you do about it?

A simple trick would be to try and feel on the fuel injectors with your hand as you crank to see if they click. If they don’t make any clicking sound, you’ve at least one faulty fuel injector. It’s best to take a professional’s help to fix this issue.

However, if it’s clogged, you can invest in an injector cleaner kit and do it yourself.

8. Engine Control Unit Issue

An engine control unit (ECU) or engine control module (ECM) is the computer that manages the main engine parameters and programming for your vehicle.

Issues with this control unit are quite rare, but if there are any, it can be one of the many reasons why your car starts then dies.

What can you do about it?

Contact a mechanic because an ECU failure usually means there are several electrical systems malfunctions that you need to get checked out.

9. Faulty EGR Valve

EGR stands for Exhaust Gas Recirculation, a valve that controls the exhaust being recirculated into the combustion chamber depending on the engine load. 

This valve helps reduce combustion temperatures which, in turn, diminishes Nitrogen Oxide emission, reducing pollution.

If the EGR valve is stuck open, it may let too much air into the intake manifold, causing the air fuel mixture to get too lean. This will result in the car starting and then dying right after.

What can you do about it?

Try to clean it first by removing the EGR valve. Spray it with a carb cleaner and scrub away with a wire brush. If this works, you won’t need a replacement!

10. Clogged Or Old Fuel Filter

A fuel filter is close to the fuel line that screens out dirt and rust particles from the fuel as it passes through before reaching the engine. They’re mostly found in internal combustion engines.

And since it filters the fuel, it’s normal for it to get clogged eventually and may need cleaning or a replacement.

But the point is, if it’s old or clogged, it can stall your car.

What can you do about it?

You can check your owner’s vehicle repair manual, where your car’s manufacturer will recommend when to change the fuel filter. Typically they suggest every five years or 50,000 miles.

However, this depends on your filter’s condition. And in most cases, your mechanic may ask you to get it cleaned or replaced every 10,000 miles.

Hope the list helps to make the fix Wesley. Have you took it in to a reputable shop lately?

I see... these are the reasons why it will not start or continue running Wesley and I believe you'll be good after you diagnose it. I will check on the codes

The codes pertains to the following 

1. P052B - Crankshaft Position Sensor failure - will require replacement

2. P054B - Powertrain control module

The engine control module (PCM) monitors Ignition Timing on initial startup. If the Ignition Timing varies excessively from where it should be, the PCM will set code P054B. A vehicle with this code should be taken in to a repair shop for diagnosis.

3. P05CC - Camshaft Position Sensor (bank 1) - will require replacement

I am thinking that once the crankshaft position sensor and camshaft position sensor replacement you'll be good. The code P0545 or the Powertrain control module issue can just be connected to the crankshaft and camshaft position sensor.

This is what the camshaft position sensor looks like

Below is what the crankshaft position sensor looks like Wesley

Can you access the vehicle at the moment?

Can you remove the negative terminal of the vehicle and let it sit for 5 minutes before reconnecting it. Sometimes resetting it can resolve the issue. I'll be standing by 

Great

I see.... You may want to disconnect the negative battery overnight and hopefully it does the trick. But if you plan on replacing the crankshaft and camshaft position sensor. Below are the videos

BMW X3 crankshaft position sensor removal - Please Click

BMW X3 camshaft position sensor removal - Please Click

I believe that the 2 sensors must be replaced to resolve the issue Wesley. But try to remove the negative battery connector overnight and see if it will do the trick. And if not then it's best that the sensors be replaced. Hope this helps Wesley and is there anything else I can help you with? I'll be standing by for your response.

Thank you

may I ask the year model of your x3 Wesley

May you please send a picture of your engine on my email Wesley. My email ad is d**9@yahoo.com

Great

I just received your audio file and I believe that the sensor replacement will resolve the issue. It suggests to monitor the camshaft position and speed  then feeds that data to the vehicle's engine control module (ECM). The ECM needs this data to control how much fuel enters the combustion chamber and ignition (spark) timing to ignite the fuel. I believe that these sensors are restricting the vehicle to start to prevent damage to the engine