E46 Fanatics Forum banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Ride of the Month Challenge!
1 - 20 of 43 Posts

·
Registered
Joined
·
41 Posts
Discussion Starter · #1 ·
Hi! :hi:

I am a new member to the forum, but I have been using it for quite a while now, and man did it help me a lot until now. I have a very unique surging/rocking problem with my car. I have used the search functions and have been to the BMW dealership and independent shop. Nobody knows what the hell is going on with my car. Any guideline or help would be much appreciated!!! Maybe someone who has/had the exact same symptoms!!!

Absolutely ZERO codes are showing up. I have no clue what's going on.

My car specs:
323i, sedan, year 2000, automatic transmission.
130.000 miles

What I have replaced so far:
- Camshaft position sensors (both, exhaust and intake) due to codes. Genuine BMW sensors.
- Fuel filter. Genuine BMW.
- Upper and lower intake boots. Genuine BMW.
- Cabin filter, air filter.
- CCV/PCV.
- A few vacuum lines that were very brittle.
- Cleaned ICV thoroughly.

The indy shop I just spent 4 hours at ran multiple tests with their Solis Ultra Snap On reader. NO codes are to be found, and the problem still persists. :banghead:

Here's the problem:
At a constant speed, anywhere between 20 - 50 mph, the car is rocking back and forth. The idle is bouncing just a tiny bit, not much. This happens when I hold the throttle steadily. I can hear a very deep sound coming from the direction of the exhaust that sounds like something like this "wooomp, wooomp, wooomp." The car will surge back and forth at the same time the sound is to be heard. I don't know how else to describe it, sorry...
At times, this same phenomenon will occur when I release the gas pedal and then press it again to accelerate. It has been like this for a while now and I would like to fix it. It doesn't matter if it's hot/cold, full/empty gas tank, this problem is always present.
This problem does not occur when I am doing above 60 mph on the highway, which is weird. I do not have a bouncing idle at a full stop.

Again, there are NO CODES! The mechanics are clueless, and so am I. We tested the MAF, switched it for a new one, no changes. We unplugged both VANOS solenoids, no changes while driving. No coolant leak, and everything seems to be working perfectly fine, except for this damn rocking.

Here are a couple thoughts:
- Fuel pump failure?
- Vanos?
- Mechanics think it might have to do something related to the exhaust?
- Mechanics also think it might be the Electric Valve #5 in this pic.

In addition, can someone please tell me where all vacuum lines are? I would like to make sure I check ALL of them for cracks.

In advance, thank you for your time/help/tips, y'all are awesome! I live in Texas, maybe someone can help me in person. :thumbsup:_a_
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #2 ·
Update:
Only one reading is a bit off when we hooked up the scanner:
It's the intake camshaft sensor. It's asking for 108 degrees, but the reading says it's reaching about 102-103 degrees. Is this something that would fit the described pulsing/rocking?
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #4 ·
annnnt1,

I researched the sound of other e46 drivers that have a faulty wheel bearing. It's more of a constant noise, rather than the pulse noise I have. Idk...
Someone else also suggested to replace the Vanos seals and maybe the pre-cat O2 sensors?
The old CCV was in really bad shape when I purchased the car, did that have an effect on the pre-cat O2 sensors? Any ideas?
 

·
Registered
Joined
·
132 Posts
Perhaps your serpentine belt is slipping...? Maybe there's some coolant or oil on it causing random slippage. You can check and clean it at no cost. Worth a try.


Sent from BimmerApp mobile app
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #6 ·
Thank you for your help. I will do some testing soon and order a new Vanos repair kit, VCG and pre-cat sensors. As soon as I get all of that taken care of, I will report back to keep you guys and others updated.
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #7 ·
UPDATE:
I found a crack in my valve cover, so I ordered a new valve cover (genuine BMW), valve cover gasket (Elring), and Vanos repair kit (Beisan Systems). After replacing/installing these parts I still have this pulsing/surging/rocking at a steady throttle between 20-50 mph. There is a misfire heard from the exhaust, a "whoomp-whoomp" sound. I haven't ordered the pre-cat sensors, maybe I should go ahead and replace them too, since I don't know if the previous owner did.

Also, I was thinking about replacing my fuel pump?

After I replace the pre-cat O2 sensors and fuel pump I will probably go to the stealership and let them do an in-depth code search if these replacements don't solve this annoying issue.... Any thoughts?
 

·
Registered
Joined
·
759 Posts
A bad flex disc / guibo can cause all sorts of vibrations in the drivetrain at certain frequencies depending on how badly it is damaged. Have you looked at it to make sure it doesn't look something like this:

 

·
Registered
Joined
·
41 Posts
Discussion Starter · #9 ·
A bad flex disc / guibo can cause all sorts of vibrations in the drivetrain at certain frequencies depending on how badly it is damaged. Have you looked at it to make sure it doesn't look something like this:

Thank you! I will check this as soon as I have a little more time. How do I get to the flex disc/guibo?

Also, I have noticed that my car rocks back and forth when driving downhill either with a little throttle or no throttle at all! I believe this issue with pulsing/surging may have something to do with my auto transmission? Any thoughts?
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #10 ·
UPDATE:

Since I last reported I have replaced the following:

- Valve cover (was leaking a little oil through a tiny crack)
- Valve cover gasket
- Vanos Repair Kit (Beisan Systems)
- Complete brake job (Brembo discs, Akebono brake pads + genuine BMW brake sensors front and rear)
- Both pre- & post cat O2 sensors (OEM Bosch, preventative maintenance)
- Motor oil (bought at the BMW dealer)

My car drives a hell of a lot better now, but I am still experiencing this low rpm surge at a constant speed/slight acceleration!!!

Next, I am buying new tires, mine are worn out. Any suggestions where to buy them? Discount codes?

I am still experiences the low rpm surge while driving at a constant speed/slight acceleration. Went to the dealer, took the mechanic on a test drive. They said it might be my differential, center bearing, or transmission. They said it's not the wheel bearing or the driveshaft. You can hear the surging in the rear area of the car. Checked flex disc, that is fine. The dealer didn't spend much time with my car, only recommended getting my software updated and buying new tires and see what happens. Any ideas guys???
 

·
Premium Member
Joined
·
28,953 Posts
So this is going nowhere fast.

It could be something as stupid is the center exhaust mounts have collapsed and the exhaust is touching/vibrating on the exhaust cross member to a flaky exhaust cam sensor or something else.

First a few questions.

1. Has the rear subframe been checked for cracking?

2. Has the fuel filter ever been replaced?

3. Has the fuel pump ever been replaced?

4. Is this just a noise or is there a loss of power?

5. Do you have an OBDII tool that supplies Live/Real Time data?

6. Tires make noise all the time, just more noise at certain speeds.

7. You speak about speed and never RPM, can you include speed, RPM and what gear the car is in?
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #12 ·
First a few questions.

1. Has the rear subframe been checked for cracking?

No, how do I do that?

2. Has the fuel filter ever been replaced?

Yes, replaced 2k miles ago.

3. Has the fuel pump ever been replaced?

I have not replaced it and don't know if the previous owner ever did.

4. Is this just a noise or is there a loss of power?

It is just a noise, no loss of power except for the surging/rocking back and forth.

5. Do you have an OBDII tool that supplies Live/Real Time data?

No, I do not. I would like to purchase one, just don't know which one. Any recommendations? I am currently looking a this one

6. Tires make noise all the time, just more noise at certain speeds.

The noise does not get louder, just a "knocking" noise.

7. You speak about speed and never RPM, can you include speed, RPM and what gear the car is in?

It occurs anywhere between 15 - 50 mph, with a rpm between 1200 - 1800. The gear does not matter, it will do it in 2. 3. 4. and 5.

I hope it's something stupid and easy to fix....
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #14 ·
How about the disa valve. Have you looked at it. Should have while you had the icv out.
Disa Valve seems to be fine. Resistance when manually trying to move the flap. Did the test with the vacuum too, the flap will slowly move to the original position.
 

·
Premium Member
Joined
·
28,953 Posts
DO NOT buy the USB cable and software as your first tool, you will be totally lost and be very limited and confused about this.

You NEED a GENERIC OBDII scan tool. $35 or less for a Smart Phone App and interface.

Tell use what smart phone or tablet platform you have.

Also read this - https://www.google.com/?gws_rd=ssl#safe=off&q=jfoj+software
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #16 ·
DO NOT buy the USB cable and software as your first tool, you will be totally lost and be very limited and confused about this.

You NEED a GENERIC OBDII scan tool. $35 or less for a Smart Phone App and interface.

Tell use what smart phone or tablet platform you have.

Also read this - https://www.google.com/?gws_rd=ssl#safe=off&q=jfoj+software
I have an iPhone 4s, Macbook Pro and Windows 7. Thank you for your help jfoj, I'll take a look at the link you provided.
 

·
Premium Member
Joined
·
28,953 Posts

·
Registered
Joined
·
41 Posts
Discussion Starter · #18 ·
What exactly will I be looking for when I download this app? Real time info? If so, what exactly? I don't have any codes, BMW scanned it.

Will this app read all BMW specific fault codes?


Sent from BimmerApp mobile app
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #19 ·

·
Premium Member
Joined
·
28,953 Posts
What exactly will I be looking for when I download this app? Real time info? If so, what exactly? I don't have any codes, BMW scanned it.

Will this app read all BMW specific fault codes?
Just because you do not have any codes or a SES/CEL/MIL light does not mean there are no problems!

I find bad O2 sensors all day long that never trigger any codes.

Fuel Trims and engine temperature info gives a lot of insight as to what is going on.

Just because BMW looked at the car does not mean there are no issues either.

Generic OBDII tools will read some manufacturer specific DTC, or trouble codes. Any OBDII code that is in the form of P1xxx is an "enhanced" or manufacturer specific code.

There is then a different set of codes that I refer to as manufacturer "specialized" codes that a do not follow the full OBDII standard, these "specialized" codes DO NOT turn on the SES/CEL/MIL and they are not read and displayed by by generic OBDII tools. Some more advanced "generic" OBDII tools can display these "specialized" codes.

But there seems to be a lot of Urban Myth that these "specialized" codes are the Holy Grail and will answer and solve all unknown problems. This is SO FAR from the case it is not even funny. These "specialized" codes MAY, but often do not, supplement the standard generic OBDII codes. BUT what happens is more often than not they are little to now help and often confuse matters. For example if you put a tools that is capable of reading "specialized" codes, it will OVERWHELM you with a bunch of out of date and intermittent items that usually have NOTHING to do with what you are looking into.

Do what you want, listen to whom you want to, but I have PLENTY of manufacturer "specialized" software and I RARELY use it. It is also rarely is going to give me a specific answer for any problem.

I used my smartphone Apps and some of my generic handheld dedicated OBDII tools FIRST and very rarely have to use anything else.

Here are some threads to give you an idea of what a $10 or less smart phone App allows you to do. VERY few, if any manufacturer "specialized" tools can do this or have this much power. This is because most of the "specialized" software was written in the 90's and by computer nerds, not people that know how to fix cars.

http://forum.e46fanatics.com/showthread.php?p=16203241

http://forum.e46fanatics.com/showthread.php?t=1050205&highlight=
 
1 - 20 of 43 Posts
Top