Well here's the 1st Do It Yourself series for the 3 Series BMW E46! I Did this to help other people because i was in their shoes and turned to youtube and the internet when i need to get something done and youtube lack the videos to really help me in certain areas...
This all started with me getting my car registered and like majority of people, you wait till the month or last min to take care of it. Well it was early January and i went to DMV to get it all done and they told me if i got the car smog and i was never notifed to smog the car and the paper behind the car registration is the smog form and yeah...
so i knew i had a check engine light (CEL) and it just comes and go; but i never felt or notice any differance expect me wasting alot of gas. So i assumed i needed a new fuel filter cause i doubt the previous owner changed it. So when time came around and school is about to start. I had to get the job done, so i thought it would be easy if i erased the CEL and smog it; well no... The guy knew i did that and said it doesnt solve anything cause the reason why it comes up because it's telling you that something has gone wrong or needs to be fixed. So i reseached the code which is a P1189 fault code. And the definiton to that is Fuel Control (Bank 2 Sensor 1) and looking at forms and i relized that people had to do alot to fix this problem like changing 02 sensors, cleaning your Mass Air Flow, Changing Fuel Filters, inspecting and replacing cracked Intake tubes, and replacing the CCV (Crankcase Vent Valve) also know as your oil seperator or your cyclone seperator.
So i first checked my Intake to see if there were any cracks and there were, so i sealed it temporarly with a sealant from my Z31. Its factory made from Nissan and its hard/soft at first and after its been soften or with heat it becomes like playdoh and it can mold on to anything and when its cooled off it becomes a plastic seal. I also check all my lines and inspected my Throtle body and my DISA and its all good to go! I did a test on the Oxygen Sensor by switching the connection cords to the opposite O2 sensor to see if the oxygen sensor near the firewall is the one that giving me the code and it was, because when i connected my scan it came up as the P1188 rather than the 89 and that confirmed what i needed to change. Same day i bought 1 Pre-Cat Oxygen sensor (Bosch) from autozone #13477. And when buying it, make sure you let them know your buying a PRE-CAT O2 SENSOR and it doesn matter if its a Right or left and Pre-cat 02 Sens are upflow its all the same with the same part code and this is a OEM fit and not the universal one where you have to splice the cord and add your adaptor you need. BMW E46 has 2 Pre-Cat 02 Sensors on the manifolds. This cost about 72 dollars for 1 sensor. And this was the day of shooting the E46 DIY#1
Once the DIY Video was done and was given a test run, the code came back along with a P1188 which is the Fuel Control (Bank 1 Sensor 1) and a P1250 Code, which means your low on fuel and i was... The light was on and i was about to hit empty. I double check the 02 sensor if i did it corectely and it was fine and i checked my spark plugs and they were worn down a bit, so i kept it in mind.
The next day i bought another Pre-Cat O2 sensor along with Techron fuel system cleaner, CRC MAF cleaner and 91 octane since i was running at 87 cause of budget restrains. And now, im no longer going back to 87, well maybe 89... but ill always go for 91 when i can.
I installed the second 02 sensor and cleaned the MAF during DIY#2 and added the fuel system cleaner when i filled up and after testing it/ grabbing lunch no codes have pop-up when im testing the MIL/CEL so far... but it came back
I then resort to my sparkplugs since they are worn and i thought its not igniting all the fuel and make me run rich and causing the ECU to adjust and stuff and yeah.. so i removed my Bosch +4 Platinums and i was sad that they didn't last that long as i thought they would and i recommended sticking with OEM which is NGK platinums which has 4 electrodes. I changed mine and the CEL still came on.. the same day as DIY#3
I had a gut feeling it was my MAF sensor going bad... then inspected imy Intake boots and saw some hidden cracks when i flex the the boot that i missed. But the major cracks were on the intake boot that is connected to the throttle body with a "Y" connection that separates and goes to your Idle Control Valve (ICV). When spot this, i visually inspect everything placed a temporary sealant using super glue on the cracks and got my car smog on the due day and it passed. I later went to my local BMW store and picked up 2. new intake boots that cost 73 dollars and placed them in and made the DIY #4 video... and i have been code free since 2/22/2011
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