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Discussion Starter · #1 ·
:facepalm:

Hi guys,
so i cant start my car the other day and my mechanic told me that i have a broken mass airflow sensor.

I googled it up and found quite a lot with price ranges from 30USD-70USD, but there are also some thats around 250-350USD. The 250-350USD ones are so called 'Genuine', 'Original' etc from ebay

Why is the price differentiate massively?

I found the logic in water pumps hepa OEM Stewart ETC, but mass airflow sensor?

Thanks guys
 

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What codes did your mechanic find? A code that says "MAF" doesn't mean the MAF is bad! Remember, codes are SYMPTOMS, not solutions. Also, the MAF is the most reliable part under the hood!
 

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Discussion Starter · #4 ·
i see, the symptoms are :

1. hard to start the car when the engine is cold.
2. took at least 7-10 ignition attempts to successfully start the car.
3. when it does start everything work as usual.
4. when i stop and start the car within an hour the car can start normally
5. stop for more than an hour i have to go through that tedious cycle again.

my mechanic told me its the MAF, but i suspected the fuel pump

thanks
 

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Discussion Starter · #6 ·
i thought so too, but my mechanic insisted that it is the MAF. He did the pressure test for the fuel pump and filter etc he said its fine. really hope hes not pulling my leg or anything.
he looked/sounded nice though ha ha
 

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Try to disconnect your MAF (remove the cable on top of it) and try to start the car. If the MAF is disconnected the ECU will use the default mapping to fuel the car (DO NOT drive it without the MAF as it can cause problems to your catalyst). But if the same thing happens with the MAF disconnected then it is probably not the MAF you should worry about.
 

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Highly unlikely it's the MAF. But if it is spend the extra money and get the genuine one. The car is very picky with aftermarket items. Odd example but It's like if your doctor ordered you to eat crab meat to heal you. You go to a seafood place...you can pay less and get imitation crab meat or pay more and get real crab meat. Sure it'll look and taste like crab but its not.
 

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. Odd example but It's like if your doctor ordered you to eat crab meat to heal you. You go to a seafood place...you can pay less and get imitation crab meat or pay more and get real crab meat. Sure it'll look and taste like crab but its not.
Very ODD indeed lol. :rofl:
 

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When the engine coolant is below specific temperature, as seen by the ECU, the ECU will go into the "open loop" mode until the engine temperature reaches a specific value. What is "open loop" mode? Basically the ECU ignores the data streams from the O2 sensors and runs a rich fuel/air mixture. It does this to get the cats up to temperature quickly. Once the engine coolant temp reaches a specific value the ECU reverst to the "normal" "closed loop" mode. During this mode, the ECU uses the data streams from tthe O2 sensors and the the MAF to determine the correct fuel/air mixture. The ECU goes into the "open loop" mode whenever the MAF is disconnected. So, if you mech thinks the MAF is bad because the engine runs better with the MAF disconnected you most likely have either vacuum leaks or the ECU isn't going into the "open loop" mode when the engine collant is cold. It could be a bad coolant temperature sensor. This sensor is located under the intake manifold and NOT in the lower radiator hose.

Have the codes read and post them.
 

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i see, the symptoms are :

1. hard to start the car when the engine is cold.
2. took at least 7-10 ignition attempts to successfully start the car.
3. when it does start everything work as usual.
4. when i stop and start the car within an hour the car can start normally
5. stop for more than an hour i have to go through that tedious cycle again.

my mechanic told me its the MAF, but i suspected the fuel pump

thanks
I doubt it's the MAF. Get a new mechanic.
 

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Fuel pressure tested fine. lol. Who cares? There's a lot wrong with that statement if you know how fuel pumps work. I won't get into it.

You cannot pretend to pimp these cars as brand new luxury cars. They will need replacements every so often. Trash the fuel, electrical, and vacuum system and try again. You'll need to do it anyway regardless of whether or not you "fix" your "problem."

Time to crack that piggy bank, E46 ownership is going to cost you.

http://e46cooling.blogspot.com/2014/10/think-youre-pimp-think-again-appeal-of.html
 

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Fuel pressure tested fine. lol. Who cares? There's a lot wrong with that statement if you know how fuel pumps work. I won't get into it.

You cannot pretend to pimp these cars as brand new luxury cars. They will need replacements every so often. Trash the fuel, electrical, and vacuum system and try again. You'll need to do it anyway regardless of whether or not you "fix" your "problem."

Time to crack that piggy bank, E46 ownership is going to cost you.

http://e46cooling.blogspot.com/2014/10/think-youre-pimp-think-again-appeal-of.html
this is an absolutely improper way to diagnose a problem and you would be fired immediately if you were a technician trying this method.
 

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Siemens VDO is OEM. Bremi is OEM for ignition coils for some, while others have Bosch
but the point being, bremi is an OEM. it doesn't matter if some cars came with parts that weren't bremi. if bremi was an OEM for bmw at any point in time with a part design (coils, MAF, whatever) they are an OEM.
 
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