[oldaccount]

Im pretty sure my fuel pump is on its way out. If my car sits overnight, or for a long period of time, it takes a very long time (15+ seconds) of cranking to turn over, or it takes multiple attempts, and then it idles very roughly for a while....but eventually it runs seemingly normal. If the engine is warm, it will usually start up fine.

This is my only vehicle, i need to get around, and BMW can not service my car/provide a loaner until wednesday.

Could it be bad for the engine to drive around with a bad fuel pump?

[CASHBY]

It is never good when you are starving the motor of fuel. i would go have it looked at by the stealership.

It does sound like it could be the fuel pump starting to die though.

[IMJUSS2NASTY]

My Car Starts Up Fine, But When It Idles Be4 Its Warmed Up, The Idling Seems Pretty Rough. Anybody Else Experiencing That? Is It A Bad Fuel Pump Or Is It Normal????

[Deveray]

I have rough cold idle too and have seen it mentioned in several threads.. I think it is normal

[wj4]

Ruff idle at cold start is normal. It should go away after a block of driving.

[thealbert]

rough idling when the engine is cold is normal but when the engine warms up and is as regular operating temperature and you still get that, then be worried about your fuel pump.

[mesier1111]

Originally Posted by IMJUSS2NASTY

My Car Starts Up Fine, But When It Idles Be4 Its Warmed Up, The Idling Seems Pretty Rough. Anybody Else Experiencing That? Is It A Bad Fuel Pump Or Is It Normal????

Just like the E46 M3----they didn't run smooth in the cold till they warmed up, sometimes they would even stall right after starting in the REALLY cold weather (seen my buddies do that more than once).

Just the price you pay for a high performance machine

[NewhouseEnt]

Having personally owned over 22 Mercedes and many other makes, I have never had one single car run rough at idle, unless there was something wrong with it.
SL55's, Viper GTR, even Porsche's only ran rough when something was absolutly wrong.

I think it's piss-poor if that is normal. My 335i has never run rough, even once, except when the fuel pump was going out. It has gotten down to 32 degrees outside and been sitting in that temp, raining out; still started and ran like glass.

If most are running right, and a few are not.....

[S4to335]

Originally Posted by mesier1111

Just like the E46 M3----they didn't run smooth in the cold till they warmed up, sometimes they would even stall right after starting in the REALLY cold weather (seen my buddies do that more than once).

Just the price you pay for a high performance machine

Disagree...it shouldnt do this if you are totally stock.

[Kbueno]

Originally Posted by S4to335

Disagree...it shouldnt do this if you are totally stock.

+2. Mine starts right up and does NOT idle rough. First 30 secs is always exhaust out of 1 of the tailpipe, then the valve opens (to flow out both tailpipes) and it sounds more normal. 2k on it so far...fingers crossed

[MacAttack]

No long starts but a subtle sputter at idle from time to time.

[Couch]

Originally Posted by Suareezay

Im pretty sure my fuel pump is on its way out. If my car sits overnight, or for a long period of time, it takes a very long time (15+ seconds) of cranking to turn over, or it takes multiple attempts, and then it idles very roughly for a while....but eventually it runs seemingly normal. If the engine is warm, it will usually start up fine.

This is my only vehicle, i need to get around, and BMW can not service my car/provide a loaner until wednesday.

Could it be bad for the engine to drive around with a bad fuel pump?

I'm showing the exact same symptoms. Except it's not a 15 second crank, more like 5 maybe.

I drove around for over year with a bad pressure regulator and fuel pump on my truck. Didn't know it, it just ran horribly at times and I kept putting it off. Never was stranded or anything. My family mechanic said it was the most clogged filter he had ever seen in his entire life. This was around 20K miles, ran great from that day forward. Not one problem.

[turbocoins]

Originally Posted by NewhouseEnt

Having personally owned over 22 Mercedes and many other makes, I have never had one single car run rough at idle, unless there was something wrong with it.
SL55's, Viper GTR, even Porsche's only ran rough when something was absolutly wrong.

I think it's piss-poor if that is normal. My 335i has never run rough, even once, except when the fuel pump was going out. It has gotten down to 32 degrees outside and been sitting in that temp, raining out; still started and ran like glass.

If most are running right, and a few are not.....

Wow, you have owned OVER 22 Mercedes. Is that 23, or 230?? And I thought that 3 was a lot!