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Old 03-19-2012, 07:58 PM   #14
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Join Date: Apr 2010
Location: Murrieta, CA
Posts: 9,223
My Ride: '94 325iC & '00 323i
Originally Posted by robwallace View Post
Hi thanks for your reply, I have already replaced the cam inlet sensor and the car was ok for around 3/4 days then did it again (hard to start after use and sitting for half hour or so and then ran rough). I am just trying ascertain what else the issue could be as I am continually getting told different things. A BMW specialist told me it could be a MAF or EJR valve too, and now I have fuel pump thrown into the equation. Any advice is welcomed! Thanks, :-)
If the problem was other than the Intake Cam Sensor, the code would be different.

Do not tell us what the code was last week, tell us the code for today. You may have fixed last week's problem, now there is a new one. You cannot assume the same problem is back. It may be back, but you cannot assume so.

Actually, the code last week is good to know, thanks for sharing. But the problem was fixed for a few days and now there is another problem. That is the way to look at this. It could be the same problem again, but the assumption must be that there is a new problem.

Part of the problem is that you don't know your car very well, which is okay. You have called it a "cam inlet sensor" at least 4 times, but this is not the proper name for the part. P0340 INTAKE CAM SENSOR. This sensor tells the car the position of the cam -- which tells the car if valves are open or closed and that triggering the spark is a good thing to do. Without a stable Intake Cam Sensor, the engine will randomly stop running. My experience with this part is limited, but the woman that had it go bad (I did the repair) reported that the car would not get underway from a stop sign or light very well -- the car would studder badly. She could turn it off and back on, and usually it would run again for a considerable amount of time. The problem was that it would kill the engine in traffic, and the implications of this are obvious.

If your independent BMW guy installed an other than OEM sensor, there is a good chance the sensor is faulty and you need another one. This is a good place to use genuine BMW parts. You can find them at many online places at far better prices than the BMW dealership.

The part you need, the intake cam sensor, creates a square wave that the computer counts as the wave form goes by. If the waveform has waves that are not the prescribed shape, then the car will not know when to fire the spark plugs, and you have an engine that runs poorly and dies at random times -- although not usually while actively engaged in driving, such as on the highway at speed.
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