Very Rough idle and cold start. Pops very loudly

[Joshbot007]

Ok so here is the background. The car has been fine. I installed and Armytrix exhaust 2 days ago and T'ed my vacuum line to this hose in between the idle control valve and this black module (idk the name see pictures). At first it was fine until I got to the gas station. I put half a tank in then started it and the idle bounced up and down for a little then back to normal, got home then took the car back out. It then went into limp mode and threw the following codes for misfires (see screenshots of codes). I would restart the car and it would idle fine with no codes for a little. After that it kept on doing this throughout the day and would seem to idle a little rough, it would only throw a code or go into limp mode when the car was idling. Now today I started it up and it was popping/cracking extremely loud during cold start (see video) and went into limp mode before warmed up. The idle is also very rough and almost dies (see video) so I figured that maybe I messed something up with the T so I added a joint (see photos) to see if that would fix the problem and it did nothing. Any ideas on what this is or could be?


Video 1

Video 2

Video 3 (notice how when it goes into limp mode the idle changes)

Thanks,
Josh

[SAMM3Y]

Sure you haven't introduced a vacuum leak with all that brass? Confirm that first and check to see if there is some sort of valve in that brass t, to be honest I'd scrap that whole piece and to get a barbed connector..

[Joshbot007]

Originally Posted by SAMM3Y

Sure you haven't introduced a vacuum leak with all that brass? Confirm that first and check to see if there is some sort of valve in that brass t, to be honest I'd scrap that whole piece and to get a barbed connector..

Originally Posted by SAMM3Y

Sure you haven't introduced a vacuum leak with all that brass? Confirm that first and check to see if there is some sort of valve in that brass t, to be honest I'd scrap that whole piece and to get a barbed connector..

I made that brass T with barbed connectors. I thought it could of been that so I replaced it with a joint that I checked to be leak free before installing, there should be no vacuum leak at that hose. Does anyone have the part # for that hose or know what that black module it is connected to is called?

[msan]

That’s the fuel tank breather valve . That valve is known to get get clogged/ go bad . The symptom is an erratic idle after filling up gas tank. The hose you cut is part 13907838439


http://www.realoem.com/bmw/enUS/show...diagId=13_1244

[BayE30]

if you introduced a new variable to your engine, and then it starts to act up, wouldnt you just take that shit off and find a better solution?

[bvrider1]

What was the intent of the T connector?

[randrews15]

Is it me or does all that brass look stupid. Fix it right with the right parts. It almost looks like you tried to fix it with duct tape. Good lord man you're driving an M and not a Ford pickup!!

[Joshbot007]

Originally Posted by bvrider1

What was the intent of the T connector?

Originally Posted by SFCM3

if you introduced a new variable to your engine, and then it starts to act up, wouldnt you just take that shit off and find a better solution?

If you look at the post and photos that is exactly what I did or tried to do. I took off the T and put a joint there to mimic an uncut line. The problem is still here

Originally Posted by bvrider1

What was the intent of the T connector?

The exhaust had valves that are vacuum operated. When you use the remote or app you can open or close them to make the car loud or quiet

[Joshbot007]

Originally Posted by randrews15

Is it me or does all that brass look stupid. Fix it right with the right parts. It almost looks like you tried to fix it with duct tape. Good lord man you're driving an M and not a Ford pickup!!

Originally Posted by randrews15

Is it me or does all that brass look stupid. Fix it right with the right parts. It almost looks like you tried to fix it with duct tape. Good lord man you're driving an M and not a Ford pickup!!

Yep its just you. They don't make connectors that are T'ed in the way you need it it has to be made to neck down to the correct size vacuum line. Brass parts come with the exhaust, this is a perfectly acceptable way to T into things as long as you use the correct sizes and sealant on the threads.

[Joshbot007]

Originally Posted by msan

That’s the fuel tank breather valve . That valve is known to get get clogged/ go bad . The symptom is an erratic idle after filling up gas tank. The hose you cut is part 13907838439


http://www.realoem.com/bmw/enUS/show...diagId=13_1244

Originally Posted by msan

That's the fuel tank breather valve . That valve is known to get get clogged/ go bad . The symptom is an erratic idle after filling up gas tank. The hose you cut is part 13907838439


http://www.realoem.com/bmw/enUS/show...diagId=13_1244

Thank you I appreciate the help. I will order a new hose. Not 100% sure of its the valve or not giving me problems because it does it all the time now not just after fillup but it's something. Thanks

[frozenm3PA]

Did you steal those connectors from under the kitchen sink?

[jcolley]

Your fuel tank vent valve is stuck open and/or an air leak on those lines. Filling the tank initiated the fuel tank leakage check, pressurizing the fuel tank.

[Joshbot007]

Originally Posted by jcolley

Your fuel tank vent valve is stuck open and/or an air leak on those lines. Filling the tank initiated the fuel tank leakage check, pressurizing the fuel tank.

Thank you, should I take the valve off and try to clean or mess with it or just replace?

[jcolley]

Originally Posted by Joshbot007

Thank you, should I take the valve off and try to clean or mess with it or just replace?

Take the valve out and see if you can blow through it without 12V applied. If so, It's failed.

[Joshbot007]

Originally Posted by jcolley

Take the valve out and see if you can blow through it without 12V applied. If so, It's failed.

Will do tonight! Thanks

[Joshbot007]

Originally Posted by jcolley

Take the valve out and see if you can blow through it without 12V applied. If so, It's failed.

I didn't get a chance to test that as I got home late but if that is true couldn't I, in theory, pinch off the line between the ICV and the fuel tank vent valve to simulate a closed valve to see if that fixes my issues?

[randrews15]

Originally Posted by Joshbot007

Yep its just you. They don't make connectors that are T'ed in the way you need it it has to be made to neck down to the correct size vacuum line. Brass parts come with the exhaust, this is a perfectly acceptable way to T into things as long as you use the correct sizes and sealant on the threads.

I seriously doubt it's me. You probably should of taken the time to do it right and make it look right. Can't complain that it doesn't run right when you do a half ass job as it would appear.

[Joshbot007]

Originally Posted by randrews15

I seriously doubt it's me. You probably should of taken the time to do it right and make it look right. Can't complain that it doesn't run right when you do a half ass job as it would appear.

It is you, that is doing it right. All because you don't think it looks super pretty does not mean its incapable to perform it's mechanical purpose and do it well. I built that specific T for that specific location to have two of the same OD with one side being 90 deg while necking to a different smaller OD in the middle. There is no practical way to do that besides building your own fitting and I spent the time to put proper sealant on the threads and hose clamps. The car is fixed now and the culprit was a leaking exhaust gasket that had nothing to do with any of the vacuum line routing. Every one else thank you for your suggestions and input

[2011_M3]

Nvm I just saw your reply

[leofong9439]

Hi Josh, is the problem fixed already? Is part number 13907838439 (Hose elbow connecting to fuel tank breather valve) causing the misfiring problem?

My 08 e90 m3 with Armytrix exhaust + valve also facing similar problem.
There are popping sound when idling and it stalls after revving it.
I believe it is a misfiring. I replaced the coils and spark plugs 10k km ago and they are still healthy.

At first I thought it was the ICV (Idle Control Valve) so I replaced it.
Then I got other new codes. (See attached image)