Killed my AFM?

[Threehz]

So my intake boot (between the AFM & throttle body) had very small cracking in it and I've been having a hot start idle issue and want to track it down, I ordered a new intake boot. I've also had a 1222 code on and off since I got the vehicle.

I just took my AFM (and air filter box & intake boot) off, looked around my intake, throttle body just to check for any weird stuff or obvious cracking hoses etc... Everything looked fine.

So I put my new intake boot on, reconnected everything and went to start the car. It starts fine and idles fine but the idle rapidly falls and then is very jumpy and it idles hella rough, consistently. Also CEL is on constantly now (before it would randomly come on after sitting idle for 10 seconds or more, and this was sporadic as well)

I decided maybe I fixed a vacuum leak and needed to let the computer re-adjust? So I unplugged the batter, let it sit dead for a good ten minutes, reconnected the battery and went to start it up again. First attempt it tried to start then died. Second try it started perfect, idled perfect for a second, then dropped down and rough idle began again...

The CEL it is now throwing is a 1215 which indicates Air Mass/Volume Sensor issues. I unplugged it and plugged it back in to make sure that was correct, connections look clean. Wires look fine...

Did my AFM die? Any ideas? I was kinda thinking maybe I just need to take it for a drive but I don't want to fuck anything up. Any help would be great, hate seeing my bimmer sad.

[Threehz]

So I took it for a test drive, seems to run well, felt a little weird at first at low speed, then when I got to the main road, check engine light went away and it seemed fine. Came to a stop light and decided to head home instead of taking it for a run.

Right as I got to the stop light in turn lane car died suddenly. Started her back up and the CEL was back.

Got home and looked around, took off intake boot to look inside again, nothing seemed strange, look from air filter side, not sure what to look for but nothing was broken looking, door opened fine. HOWEVER,

There is a rattle. When I open then let the door close or tap the AFM there is a rattle somewhere inside... Something broken?

[cunninglinguist]

How did you do the MAF conversion?

[Threehz]

Sorry AFM... After posting all that I realized that it's an AFM..

[alB5]

i had similar issues, turns out i didn't plug in the afm correctly. i doubt that's your issue though lol

[roguetoaster]

This would be an excellent time to pop the top on the AFM and check for condensation, severe wear on the carbon track or anything obviously broken. Of course you can try and start the car without the AFM plugged in and see if you have the same issues. Otherwise just check again for missed connections on vac lines or maybe check to make sure the IACV and TPS are plugged in.

[Threehz]

How do you go about popping the top of the AFM? It appears to be glued in place no?

I got some throttle body cleaner and I'm going to get at the ICV as soon as I can. I've looked everything over and nothing appears unplugged, I've checked the plug on the AFM about 5 times now so that is certainly correct.

[Ryann]

This would be an excellent time to pop the top on the AFM and check for condensation, severe wear on the carbon track or anything obviously broken. Of course you can try and start the car without the AFM plugged in and see if you have the same issues. Otherwise just check again for missed connections on vac lines or maybe check to make sure the IACV and TPS are plugged in.

^This is good advice.

[roguetoaster]

How do you go about popping the top of the AFM? It appears to be glued in place no?

I got some throttle body cleaner and I'm going to get at the ICV as soon as I can.

Just carefully pry the cover off, I cannot recall if it is glued or more like RTVd in place, but exercise caution so you don't break a corner of the top. When I took the lid off of mine it had some condensation and track wear which may have been causing the somewhat rough idle, to fix this I simply used a hair dryer to dry the components, and GENTLY bent the track "needle." I doubt this is related to the IACV, I just wanted to be sure you had plugged it in.

[bmwman91]

You didn't kill your AFM. Those things are way more robust than people give them credit for (people assume that because it is electrical that it must be weak or something). It's a damn glorified potentiometer. You could drop it on the ground from 3ft up and it would work fine.

It MIGHT be that one of the little terminals in the AFM connector is loose & not seating on the pins. Pull back the rubber boot on the connector & make sure that all of the circular female terminals are all still fully seated in the housing.

It sounds to me like you have a big vacuum leak somewhere. Did you reconnect the breather hose from the bottom of the intake boot to the rubber thingy under the throttle body? Did you reconnect the hose to the charcoal canister? If I had to guess, yanking the breather hose out of the throttle body split open the part it plugs into under the throttle body and now tons of air is leaking into the ICV. Those rubber connector things are pure dog shit and always split.

[roguetoaster]

In addition to the learned bmwmans comments above did you make sure to swap over the metal support piece (just a small near hoop) inside of the intake boot, presuming you had one in the old boot. Without it the boot can deform and cause issues, probably not your issue, but worth a shot. More probable is a missing plug in the bottom of the new intake boot.

[Threehz]

Boot has plugs, ICV to boot is secure, all ICV hoses are secure, metal ring inside boot came with the new boot, all TO-charcoal hoses appeared secure, every other damn hose I've double-checked, tomorrow I will triple check, take the AFM apart and investigate..

Thank you all for the good advice, I'll try and check as much as I can tomorrow.

There is one hose I need to deal with, does anyone know what type of hose connects from the fuel rail (maybe?) to the throttle body? It's a very small hose and has tiny cracking in it. It has been like that since I got the vehicle and I'm certain it is not the issue, however I want to replace that hose before it does become an issue.

By the way Ryann, that video is great, thank you again, hopefully that'll do the trick!

[Threehz]

Just took apart the AFM, looked hella clean and fine inside, some rattles like crazy when I let the AFM's door close though, nothing that is visible. It sounds like it is coming from under that spring area, is this normal?

Anyhow I cleaned the track and sensor and everything although it looked pretty good already. Sealed it and put it back on.

Started the car just to see if that somehow fixed anything.. The idle is pretty good, but it isn't super smooth. And.. The CEL 1215 is still there.

Now here is one thing I found. On the intake bellow, bottom-side, and the end that connects to the throttle body.. There is a hole on the bottom, when I first got it and looked at it, I was certain it was plugged. However, when the engine is running and I put my finger on the hole, there is definitely suction. Is it supposed to be like that?

[Marauder42]

...

Now here is one thing I found. On the intake bellow, bottom-side, and the end that connects to the throttle body.. There is a hole on the bottom, when I first got it and looked at it, I was certain it was plugged. However, when the engine is running and I put my finger on the hole, there is definitely suction. Is it supposed to be like that?

Sounds to me like you found at least part of your problem. Pretty sure it's supposed to be plugged. At least it is on mine.

[Threehz]

Well plugging it with my finger and unplugging appeared to make no difference in the idle.

Can you just confirm it for me? Just start the car and put your hand or finger around it, mine has an easy to feel suction.