05 645CI Shaking/Rough Idle At Stop

Ok I have been through the search and dont really see any other posts that are like mine so here goes.

When I am at a stop the car shakes.

The RPMs DO NOT fluctuate enough to see on the gauge.

This happens when the car is cold or warm, hot.

No error codes or messages on the dash.

I ONLY use high octane Mobile gas.

The car does hesitate a tiny bit SOMETIMES when taking off from a stand still.

Any help would be appreciated.

-Jeff

does it also shake after u start it after being off?

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Yes it does.

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I've experienced the same issue, over time it will progress and you'll notice the hesitation increases when you accelerate from a stand still. The issue I had was a vacuum leak.

Mine did that yesterday, I filled it up with gas before the problem started. Mine surges more often since I changed my thermostat. I know this should not make a difference, but these cars are strange! Put in a bottle of Techron to see if it will help!


Good Luck!

Did the TechRon already. Taking it to the dealer in 2 weeks and will update this post.

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Hi all, I have the same problem..virtually identical including the fact the rough idle doesnt really affect the revs. Diagnostics say thermostat is stuck but judging by what was said above replacing that could make it worse?
Any help would be greatly appreciated.

A.j

If the diagnostics say thermostat stuck, replace the thermostat. This is a very common problem.

Good Luck!

Hi HerbP
Thanks for the reply - is that likely to solve the problem of unmask it and make it worse as you suggest in your previous replies?

As stated earlier, these cars are a bit strange when they start to have problems, too much electronics. The best bet is to be able to read the codes. I've seen post on here that the replacement of the thermostat solved the problem. Also a bad coil could be causig the issue as well but you wont know for sure until you get the fault codes read.

The strangest thing about the thermostat is, that it can cause the motor to swing up & down. A rough engine idle would most likely be from a vacuum leak. From chasing a very small o-ring leak, it can drive you crazy. DIS will give you the codes to point you in a certain direction, after you that you are on your own!

For a rough idle I would 1st inspect the 2 front vent hoses, these become very brittle over time. 2nd I would change the 2 crank case vent valves, better known to most as a PCV valve.

Hope this might help!

thanks for your help. getting the diagnostics done next week so will keep you posted. my engine management light just came on-not sure if this is related but whatever it is should come up next week in the diagnostics....

a.j.

What was the issue?

Originally Posted by BadboyzTn

What was the issue?

+1.
I have similar issues. Rough idle and hesitation sometimes. I keep getting the thermostat error code too. I replaced the thermostat, but still getting the same "increased emissions" message after I reset the SES light. I've also now run techron in it and replaced the CCV valves with the newer ones that eliminate the vent hoses too. No change.

Frustrating. I'm thinking maybe I got a bad new thermostat too? Long shot, but thinking of replacing it again.

I too have same issues. I really want to buy a code reader is there one that is user friendly? Or one easy to learn. I've done everything but replace thermostat is that a difficult task?

It takes around 30 to 45 minutes to change the thermostat. It would also be a good time to install fresh antifreeze, since you are going to loose some. A basic code reader is not going to do much on a BMW. You could purchase the one of the Bavarian Tech readers, that will allow you to do some troubleshooting & rests. Another option would be to purchase an OBD2 cable that works with DIS or INPA. There is much discussion here on the boards that go into detail.

Good Luck!

Originally Posted by herbp

it takes around 30 to 45 minutes to change the thermostat. It would also be a good time to install fresh antifreeze, since you are going to loose some. A basic code reader is not going to do much on a bmw. You could purchase the one of the bavarian tech readers, that will allow you to do some troubleshooting & rests. Another option would be to purchase an obd2 cable that works with dis or inpa. There is much discussion here on the boards that go into detail.

Good luck!

+1

I just scanned the car with a bmw specific tool and it came up with the 2ef4 code which looks like it is the thermostat. I guess I'll replace it again.

I'm usually skeptical of thermostats making it run rough but you never know with these cars. Anyway, if this doesn't fix it for you, I found that in my case, the cure for an occasional spat of rough idle... to the point that it would throw a 'cylinder misfire' code for some cylinders... was: Spark plugs.

Highly recommend if your car has more than 50k miles. They say 100 k interval, but I found that for my car, this was waay too long.

2¢

I did just change my plugs as well a couple weeks ago trying to rule them out. No change.
I ordered a new thermostat again, we'll see if that helps anything. I've also read that sometimes part of the wiring harness that goes to the thermostat goes bad on these motors, but I think its earlier builds than mine which is a 5/05.

I have the same exact problem. I have done the following and still the problem persists .

1. New Thermostat
2. New Spark Plugs
3. New Coils
4. New CCVV (PCV) installed
5. New Battery
6. Coolant flush done and no leaks

Its getting worse now and it has rough idling. No error codes at all .

Did your problem get solved - if so, what was the solution?

Thank You!

I did change my thermostat again and made sure I got the OEM brand, that got rid of the light and it has been off now for a couple months now at least.

Idle is still rough. I changed the plugs, thermostat (obviously), and CCVV's. I did have one coil go bad a couple weeks ago and replaced it. The car was really running like crap and the light came on when it went out. I just ordered 7 more that should be here this week so I can replace the rest since I figure its only a matter of time for them. We'll see if that does anything. But you mentioned you've changed them with no effect. I've also cleaned the crap out of the throttle body and MAF sensor, with no change.

The other thing I have read somewhere was that the valvetronic programming can be updated and help. I pulled mine up on my scanner and it looks like it was last updated in 2009, not sure if that is still the latest programming for it though. If anyone knows, I'd really like to know so I don't waste time/$ at the dealer to have them look into it.

I wonder what the rough idling might be ... I hope it gets figured out. Let us know about the valvetronic programming!

Have you checked for vacuum leaks? Check hoses and spray some starting fluid around places that are known to have leak issues. If there is a leak the idle will smooth out or stall all together.

Originally Posted by five liter

Have you checked for vacuum leaks? Check hoses and spray some starting fluid around places that are known to have leak issues. If there is a leak the idle will smooth out or stall all together.

Yeah, I've hosed everything down in there pretty good and no changes. When I replaced the CCVV's I used the new style that don't have the hoses. I capped off the nipple on the intake hose. So those hoses won't ever be an issue.

My coils get here Wed, so I'll see if they make any difference.