2007 335i shaking on acceleration

[sfrolich]

A few months ago I brought in my 2007 335i for its last set of small fixes before the warranty ran out. The service advisor looked and found a bunch of service bulletins on the car. I know the HPFP got replaced and a software upgrade occurred. I think that I got new fuel injectors too but I’m unsure because I cannot find the receipt.

Anyways, when the engine is cold during moderate to heave acceleration I can feel the engine shake or misfire (not sure if it is a misfire though). I can feel the stick shift shake so I know it is coming from the engine. It seems to have all the power it did before and I’m not getting any engine lights on the dash. The car starts normally (no long cranking). So my questions are:
What could it be?
If the car ever throws a code does a dash light always go on or do I need to hook it up to a computer to find out?
Do you think it is related to the work I had done a few months ago?
Thanks!

[floydr]

Were the spark plugs replaced at 45K as specified?

[sfrolich]

Were the spark plugs replaced at 45K as specified?

The car only has 35k on it. I'll see if I can find out what was replaced on it a few months ago.

[mryakan]

Just a few things to eliminate:
- Where do you fillup gas?
- What grade do you use?
- Have you tried a different gas station, preferably a top tier one?

The problem may or may not be related to gas, but it would not hurt to eliminate that possibility if you have not already done so.

[sfrolich]

Just a few things to eliminate:
- Where do you fillup gas?
- What grade do you use?
- Have you tried a different gas station, preferably a top tier one?

The problem may or may not be related to gas, but it would not hurt to eliminate that possibility if you have not already done so.

I'm using 91 octane from Chevron and 76 lately. Are thoes top tier?

Also I usually drive the car one or two times a week but I do drive it 30 miles each time.

[lqaddict]

I'm using 91 octane from Chevron and 76 lately. Are thoes top tier?

Also I usually drive the car one or two times a week but I do drive it 30 miles each time.

Premium fuel should be used.
I am not sure if MAF cleaning applies to BMW, if it does cleaning of MAF sensor might be beneficial.
Have the spark plugs checked as well.

Sent from my Nexus S 4G using Tapatalk

[sfrolich]

Premium fuel should be used.
I am not sure if MAF cleaning applies to BMW, if it does cleaning of MAF sensor might be beneficial.
Have the spark plugs checked as well.

Sent from my Nexus S 4G using Tapatalk

Sadly, 91 octane is the highest available in California unless you pay the big $$$ for 100 octane.

[mryakan]

91 oct should be good enough. I believe Chevron is also top tier (see www.toptiergas.com). It could be the plugs, or maybe carbon buildup!

[sfrolich]

91 oct should be good enough. I believe Chevron is also top tier (see www.toptiergas.com). It could be the plugs, or maybe carbon buildup!

What is the best way to get rid of carbon buildup without ripping the head off?

Also if the car ever throws a code does a dash light always go on or do I need to hook it up to a computer to find out?

[derbim]

If you do have carbon build up on the tops of the valves, you will need to have the head pulled and the valves cleaned. My dealer just got a machine from BMW that will do this, but they have not yet decided on how much to charge. The first time my valves were cleaned, it required blasting with walnut shell parts. Soaking in various cleaning chemical solutions barely touched them. 100k miles later, my valves are still clean, and I attribute this to changing the oil I use.

The symptoms you describe could be the result of several different things, and you'll need to eliminate them one by one. And yes, if your vehicle throws a code and one of the lights on the dash is on, I recommend having the dealer read the code to determine the cause. This is not fool proof, however. A cylinder misfire could be the result of software, or a bad injector. It also could be caused by acclimation, which is the software equivalent of the ECU memorizing the most recent engine settings. If you suddenly change one, (for example just flooring it away from a dead stop, and you have not done that before), and the ECU has not seen that before in its memory, it takes it a bit to "catch up", and write this new set of codes (i.e., fuel demand, fuel pressure, throttle demand, and so forth) in its memory. It can throw a code as a result. Turn off. Restart, and it will run fine. Could be bad fuel. Dirty valves usually are accompanied by erratic idle. No matter what you are doing throttle-wise, they cannot function properly. Lots of problems with injectors, and they have had recalls on those. Not likely a fuel pump problem. That is almost always indicated by a cold start problem, followed by a SES light.

Good luck.

[sfrolich]

If you do have carbon build up on the tops of the valves, you will need to have the head pulled and the valves cleaned. My dealer just got a machine from BMW that will do this, but they have not yet decided on how much to charge. The first time my valves were cleaned, it required blasting with walnut shell parts. Soaking in various cleaning chemical solutions barely touched them. 100k miles later, my valves are still clean, and I attribute this to changing the oil I use.

The symptoms you describe could be the result of several different things, and you'll need to eliminate them one by one. And yes, if your vehicle throws a code and one of the lights on the dash is on, I recommend having the dealer read the code to determine the cause. This is not fool proof, however. A cylinder misfire could be the result of software, or a bad injector. It also could be caused by acclimation, which is the software equivalent of the ECU memorizing the most recent engine settings. If you suddenly change one, (for example just flooring it away from a dead stop, and you have not done that before), and the ECU has not seen that before in its memory, it takes it a bit to "catch up", and write this new set of codes (i.e., fuel demand, fuel pressure, throttle demand, and so forth) in its memory. It can throw a code as a result. Turn off. Restart, and it will run fine. Could be bad fuel. Dirty valves usually are accompanied by erratic idle. No matter what you are doing throttle-wise, they cannot function properly. Lots of problems with injectors, and they have had recalls on those. Not likely a fuel pump problem. That is almost always indicated by a cold start problem, followed by a SES light.

Good luck.

Thanks for the info. Can the car throw a code and not have a light show on the dash?
This just had to happen to me a few months out of warranty!

[sfrolich]

I took the dar to the dealer last week. The computer didn't have any relevent codes in it. The mechanic said he could feel the problem I am talking about so he reset the computer and kept it a day to test again. The next day it had the same problem. He said the fuel injectors were fine and that he suspects it to be one of the coils. He could replace them all for about $1000 or he said wait for the computer to throw a code and bring it in.

I can understand the reasoning for doing this but I'm annoyed that I need to drive a broken car until it breaks more. I might bring it to the Dinan shop near me to see if thay have any ideas.

I'll keep everyone updated on when the solution is found.

[andrew b]

100k miles later, my valves are still clean, and I attribute this to changing the oil I use.

Apologize to the OP for the off-topic, but to what oil did you change that you attribute this? Have a new-to-me '07 335i that will be due for oil soon (7.5K, I just am not comfortable waiting the 15K BMW suggests).