pcy

Disconnect the MAF (Mass Air Flow sensor) and try to start and let me know the result.

pcy

Usually, there is a valve at the end of fuel rail for fuel gauge connection. I don't remember if N52 fuel rail has. If there is a valve at the end, connect fuel guauge and see if there is fuel pressure.

Before you test the fuel pressure, when you insert the key and turn the ignition to position 2 (don't try to start the car), do you hear fuel pump pressurizing the system for few seconds? If necessary, pull out the rear seat bottom and listen for the fuel pump humming.

E60I

Oh my god, YOU ARE A GENIUS!!!

After the MAF is disconnected, the car starts and run on my first try. It runs rough! How long should I let the engine run to see if it can smooth out?

While the car was running rough, I connected the MAF back. As a result, the engine shuts off.

How can we fix it?

Thanks!

zgilbert

Disconnect your negative battery terminal. Let the car sit for 15 minutes. Then reconnect the cable.
Turn on the ignition but DON"T START the car. Let it sit for 1 minute with the ignition on. Then turn off the ignition. Now start the car.

Doing so resets the PCM.

Didn't you say the car runs for APPX 3sec?????

zgilbert

Gotya on the MAF!!! Try resetting the PCM as I described above.

E60I

Hi zgilbert and Pcy,

I did the reset like zgilbert suggested. The car cranks for a second and that's all.

Bentley service manual suggests to check and clear fault codes from ECM memory after reinstalling mass air flow sensor. How do I do that?

I do have INPA installed in my laptop. I can do it if someone would kindly show me the steps.

Thank you so much!!!

pcy

I think the MAF was damaged while removal/reinstallation process
OR
the MAF was defective prior to the starter installation.

Try cleaning the MAF sensor with MAF sensor cleaner (auto parts stores sell them). The part that looks like a wire/resistor in the MAF is a delicate part. While trying to clean it, don't let the spray nozzle touch that wire part. Spray the cleaner liberally, let it dry, and install. If this doesn't work, I am afraid you may have to buy new MAF,

zgilbert

I agree with pcy on this. If the MAF unplugged allows the car to start, you should get a Check Engine Light. If you plug in the OBDII code reader the code should be PO101 or PO102 for MAF.

Hopefully when you clean it, all is well. Good Luck!!

zgilbert

BTW I use an Actron OBDII code reader tool. It makes ease of reading erasing codes on all brands. I have used it on Ford/Chevy/BMW/Porsche/and Toyota.
Buy Actron Auto Scanner OBD II Code Reader CP9575 at Advance Auto Parts

I haven't used the INPA program before, so I can't help there

zgilbert

Found this.... But gotta go.. gotta pack and get the family out of town for Thanksgiving

Good Luck!