In Reply to: Re: 94 540 rough start any tips? posted by keith on April 14, 1999 at 09:24:26:
: : My 1994 540i automatic has been starting a little rough the last few days. I live in the SW and its garaged, so it's not due to cold weather. What happens is it turns over then it seems to struggle a bit to get to full idle(thought it might be the battery). Rather than turning right over there is about a 5 second period where it seems like its grasping for air or fuel.
: : This only seems to take place in the am. In addition it seems to take a little while to warm up in the am. before the throttle responds appropriately.
: : Is it a gas problem(bad gas) an injection problem or what?
: : Anyone had a similar problem.
: I have a similar problem with my 94 530iA. When the car is cold and has been setting overnight it starts roughly for about five seconds, then "catches" and idles normally. It only seems to do this after sitting for a good while and seems to be worse the colder the weather (I live in north Alabama). I think it may be a software problem. There was a technical service bulletin issued in February 1996 addressing startup difficulty when the engine temperature is below 40 deg C (104 deg F) and poor acceleration during the warmup phase (bulletin number 120196). My car had the DME chip and thermostat replacement performed by the dealer to address the sulfur-related Nikasil block problems, but has not had the newest chip installed per this latest service bulletin. Since, per the service bulletin, it is covered under a 6 year, 100,000 mile warranty, I am probably going to take my car in to get the new chip. I'll bet your problem with your 540i is similar to mine, particularly if you've had the new sulfur-related chip and thermostat installed.
We have the same car and a year ago learned that there was potential for cylinder wall degradation from certain gas. It was most prevailant down south but when we took our car in last month for a checkup, they performed a compression check and found that the car qualified for warranty engine replacement. You may want to get yours checked out since the symptoms are rough idle and difficulty starting.