My twerking e34

[malakush]

Alright so I'm going to try to describe the best I can.. my 520i (m50b20 automatic) likes to bounce like a instagram twerkqueen. She mainly does it when stopped and in gear.
The rpms are slightly fluctuating when she does it, and the whole car is rocking back and forth.
I took her to a mechanic shop this morning, and after fiddling with the spark plugs the mechanic tried unplugging the MAF, he thought he had found the problem, and claimed all I needed was a new MAF. I said alright, compensated him for him for his troubleshooting and left the shop. (We disconnected the MAF)
Only to experience it worse than ever before, she was dancing and booty shaking like never before. She was now doing it pretty much at every red light, and I had to switch between neutral and drive for the first time ever, to avoid the embarrassment and the looks from my fellow road users.
After around 30 minutes of driving, she was back to only doing it every now and then.
I am now thinking that it obviously has nothing to do with the MAF (I reconnected it), and considering he checked her plugs, and it triggered something, it must have something to do with sparkplugs, coils or coil pack.
I personally mentioned the ICV, but he was convinced it's not related.
I hope someone can virtually diagnose my twerkqueen, and help me turn her into a innocent nun. Hopefully someone here has experience with this and can pin point the problem before I order coils ect.
Thank you all in advance!

[moroza]

This was amusing to read.

Smoke test the intake. Diagnose or outright replace the oxygen sensor. Inspect and probably replace the ignition resistor.

[Sleepyhead97]

Ya its a vac leak or bad maf.

[malakush]

This was amusing to read.

Smoke test the intake. Diagnose or outright replace the oxygen sensor. Inspect and probably replace the ignition resistor.

I want to thank you for taking the time to read and answer.

I have been googling since posting, and I have reached the point where I think I need to find a way to diagnose it. Get all the fault codes before touching anything, because litterally every person sharing their thought has told me something different.

Do you have any idea on how to do that? Or should I try and call around and see if any nearby shops have a scan tool?

Thanks again!

X

- - - Updated - - -

Ya its a vac leak or bad maf.

But shouldn't disconnecting the MAF have "hidden" the issue then? I mean while it was disconnected she shouldn't have been acting up? or am I wrong?

- - - Updated - - -

https://www.bimmerforums.com/forum/s...e-pedal-faults

Should I maybe try this?

[Sleepyhead97]

Have you tried the stomp test? That tells codes. I jad a badmaf and torn boot it did the exact same thing lol.

[Sleepyhead97]

Yes do the stomp test. I tried 70 something times before i got it to work. Key to pos 2, stomp 7 times smooth but quick and it works 30% of the time. Full pedal travel same speed each stomp be done within 5 seconds

Most people get it with 5 stomps not me

[malakush]

Yes do the stomp test. I tried 70 something times before i got it to work. Key to pos 2, stomp 7 times smooth but quick and it works 30% of the time. Full pedal travel same speed each stomp be done within 5 seconds

Most people get it with 5 stomps not me

I wish! But my car is european, and does not even have a check engine light.. so no stomp test for me i guess

check this link if you have time, and tell me your thoughts

https://www.bimmerforums.com/forum/s...e-pedal-faults

[moroza]

Pre-OBD check engine lights are near-useless. Forget about scan tools; the diagnoses I mentioned are straightforward analog/mechanical tests:

1. Smoke machine. They're amazingly useful for detecting intake leaks, which is most likely your problem. They can be improvised with cigarettes, though that's not as reliable as a real one with a pressure regulator. Cheap ones are ~500DKK and work just as well, if not as easy to use, as ~5000DKK professional machines.
2. Look up in the Bentley manual (or possibly factory service manual?) for how to test the oxygen sensor. You can also narrow down the problem simply by unplugging the sensor (4-prong round connector below the intake manifold) and observing any changes.
3. There is a 240ohm (2W?) resistor inside the black plastic wiring box near the fuel rail. It's probably cracked. It's in series with the ground wires of all six ignition coils. Replace it with a generic 240ohm 2W or higher-rated resistor, soldered in.

[Sleepyhead97]

Moroza, i respect your experience but my car told me the maf was bad . was the easiest diagnosis ever. That being said a multimeter could tell me the same. I agree real detective work is usually the best course of action as you stated

[moroza]

Sure, they're right sometimes. That said, I've seen destroyed MAFs fail to set a code.

[malakush]

Alright, just giving you guys an update.

I sat down and tried really hard to remember the time I felt the rocking bak and forth for the first time. And I wasn't sure, if I had felt it before, but somehow out of sheer brainpower and digging in my memories, I remembered the first time being shortly after installing a performance chip I had bought on eBay. (I actually didn't think it was related) ... but I had booked a troubleshooting at a shop that specialize in BMW. It was quite pricey, so I thought.. won't hurt to go back to the OEM chip to see if I can spare the expense.

I walked over to my underground parking lot, pulled out the ECU, and swapped the chips.

I was unfortunately met by a car that wouldn't start anymore. It cranked, but no start. I swapped back to the performance chip, and same problem. I was very frustrated.. but after trying various things, I came to my senses and called the national equivalent to triple A.

They came with 2 flatbeds and a 4x4 volvo to pull out my e34 from two stories underground. It was chaotic as the flatbeds were basically blocking the whole road.

But in the end they got out my car, loaded it up on the flatbed and drove it to the shop for me. I called and told the shop about my adventures inside the ECU, and it didn't take them long to conclude that I had somehow fried the ECU.

They ordered a new (used) one for me and plugged it in. Car started right up, and for the past three days there has been no running rough/RPM issues (knock on wood).

So I guess I learned the hard (and expensive) way that you should never install eBay ECU chips and probably not fiddle with your ECU, and I recommend everyone to stay away from eBay cr*p.


I really hope I am not jinxing myself by making this post, but for now..... problem seems solved, and I can't believe I basically asked for it and payed a lot of money to have this experience.


Merry christmas everyone! I hope you and your families are all safe and healthy in this global situation.

- malakush

[Sleepyhead97]

Yikes! Glad you got it fixed. I have an ebay chip in mine lol works well, but there are many to choose from and prob best to avoid