[therealm3]

Hey guys, I wanted to see if others are experiencing a similar thing with the 335. I don’t think this is the “cold start idle” issue because it happens when the car is warmed up and driven for awhile. Basically I come to a stop at a light and the idle goes to 600 per normal operation and then randomly there is a miss. Very noticeable as the whole car kind of shakes once. No surging or oscillating rpm afterwards just 600 rpm again. It is quick so there is no drop in rpm either. I have this happen pretty regularly but no check engine light. I hooked up the OBD2 scan tool and there are no stored codes either. Any one else having the same thing?

I am hesitant to take it into the dealer after the disaster I had with my E46 idle issues. 7 different trips to the dealer, weeks of total time in the shop and in the end I got a pat on the butt and told by BMW field engineer that the idle problems I documented very well using OBD2 Data logging were “normal”.

[Aeroav8r]

Yes, I wont say it's a misfire, but a definite one time 'shudder' about 10-15 sec. after coming to a stop in Drive or Sport.
335i Sedan, Step, 1700 miles

[therealm3]

Exactly. If not a misfire (lack of spark, lack of fuel, etc.), then what would create this kind of situation?

Originally Posted by TS335i

Yes, I wont say it's a misfire, but a definite one time 'shudder' about 10-15 sec. after coming to a stop in Drive or Sport.
335i Sedan, Step, 1700 miles

[Aeroav8r]

Originally Posted by therealm3

Exactly. If not a misfire (lack of spark, lack of fuel, etc.), then what would create this kind of situation?

It feels as if something is being switched over - may be the exhaust flapper valve doing its thing.

[JEllis]

If your A/C is on then that is most likely the culprit...

Jason

[therealm3]

Originally Posted by JEllis

If your A/C is on then that is most likely the culprit...

Jason

nah. I don't use the AC unless its really hot outside.

I would not be surprised if it turns out to be slightly imperfect code due to first year production....

[sdiver68]

Originally Posted by therealm3

nah. I don't use the AC unless its really hot outside.

I would not be surprised if it turns out to be slightly imperfect code due to first year production....

Mine does not do what you describe, outside of the cold start time window.

[SROC3]

used to happen to me too and i solved it by doing the following:

- at start I idle for approx 1 minute to let the oil circulate around the engine
- I drive off after but DO NOT go over 3800 rpm until the engine has reached near normal operation temp of 210 (200 is fine).

The above has worked for me very well. Hope this helps

[Aeroav8r]

Originally Posted by SROC3

used to happen to me too and i solved it by doing the following:

- at start I idle for approx 1 minute to let the oil circulate around the engine
- I drive off after but DO NOT go over 3800 rpm until the engine has reached near normal operation temp of 210 (200 is fine).

The above has worked for me very well. Hope this helps

This is something different, it happens about 15-30 sec. after coming to a stop, indifferent to hot or cold oil, engine or air temp. Did it to me this morning at Jack in the Box - foot on the brake, in Drive, it's a slight dip in the idle and it makes the car rock side to side ever so slightly.

[grkm3]

try a different gas station

[therealm3]

Originally Posted by grkm3

try a different gas station

What would that do?

The car has enough miles and tanks of gas (all 91CA) with the problem there to eliminate low octane or bad gas. Oil temp is not an issue either: 230 and it will still do it.

[Ryan(e92)]

Mine has a quick blip during cold start up. Doesnt happen all the time. Ive got a 6 speed.

[Aeroav8r]

It's the exhaust valve flap on mine, confirmed it yesterday.

[Jay@ATP]

Originally Posted by grkm3

try a different gas station

+1

Dont buy gas from no-name stations. Only use Chevron, Shell, 76, etc.

Not saying this will fix the problem, but every turbo owner should use higher quality gas.

[tigger184]

How did you come to the conclusion it was the exhaust flap causing the problem?

[Aeroav8r]

Originally Posted by tigger184

How did you come to the conclusion it was the exhaust flap causing the problem?

Drove the car for 30 min., parked the car, engine running in Park. I exited the car, walked to the back of vehicle, 30 sec. later heard a loud sound that is the valve closing ('clasp' sound), car shuddered for a millisecond at the time the valve closed.

Try it.

[tigger184]

Would it be safe to assume replacing the exhaust system will solve the issue? Is there a design flaw in the BMW exhaust system?

[Aeroav8r]

Originally Posted by tigger184

Would it be safe to assume replacing the exhaust system will solve the issue? Is there a design flaw in the BMW exhaust system?

Golf tee.

[ICALL]

I believe I read someone else stopped the valve from closing in the "Under the Hood (NA-Engine) / Drivetrain / Exhaust Modifications
Everything engine and drivetrain related" forum area and they said the car's performance deteriorated. Explaination was the closing of the exhaust increased torque at lower levels.

Replacing the exhaust system shouldn't be a problem, but anyone looking to just stop the valve from closing may have a problem

Disclaimer: I know NOTHING about this stuff. Only trying to reiterate what I read on another post. People with more knowledge, feel free to chime in.

[Aeroav8r]

Originally Posted by ICALL

I believe I read someone else stopped the valve from closing in the "Under the Hood (NA-Engine) / Drivetrain / Exhaust Modifications
Everything engine and drivetrain related" forum area and they said the car's performance deteriorated. Explaination was the closing of the exhaust increased torque at lower levels.

Replacing the exhaust system shouldn't be a problem, but anyone looking to just stop the valve from closing may have a problem

Disclaimer: I know NOTHING about this stuff. Only trying to reiterate what I read on another post. People with more knowledge, feel free to chime in.

That's why I'm leaving mine as is: it's not a problem to me, and the golf tee remedy will not be employed.

[RiXst3r]

I think the change in backpreasure from the valve closing causes this, I noticed it more when i was using BP gas, I switched to shell, and it doesnt do it any more...