Hi all,
Our 1995 540iA has developed a few problems; I'd appreciate everyone's help in trying to diagnose/solve/fix them.
First, a little history: the car was bought a little over a year ago. Single owner (verified), service history, 110k miles. Both the Audi dealer we bought it from (Audi Center Oakville in Oakville, ON) and our BMW dealer ran thorough checks on it last summer and gave it a very clean bill of health (factory spec compression levels, etc.) We drove it 10k miles or so from June-October of last year, and had absolutely no problems with it. No squeaks, rattles, anything.
Since then, we've run into a few minor issues.
1. In early November, we filled the car up with gas -- the same premium 91 octane we always use. Almost immediately, the vehicle ran rich and idled rough. It's smooth once you get going. The M60 isn't down on power, and we seem to be getting around 22-24mpg, which is standard.Our diagnostic tool gave us an O2 sensor code. We've replaced one sensor, but the problem persists. Whether or not our mechanic replaced the wrong sensor, or whether the O2 code was suggesting that something else was up, I'm not sure. I realize there are literally dozens of things that could bring about this problem. What's curious here, however, is that the problem came up almost immediately after filling the car. Is this a case of bad gas, water in the lines, a bad filter....or is it mere coincidence? In any case, the car was store over the winter, and the issue hasn't gone away.
2. While the car was in storage, an unknown fluid leaked out. We think it may be auto transmission fluid, but can't be entirely sure. If that is the case, the 5HP30 doesn't seem to have been affected: it shifts smoothly, doesn't slip, and functions as intended.
3. This issues came up after storing the car over the winter. It wasn't present last fall. While holding a constant speed, a muffled (and sometimes pronounced) vibration noise is emitted (possibly from the back of the car, not sure) at between 50 and 60 mph. Above that it goes away. It also dies off when you accelerated, only come back once you're again holding a speed. The tires are new and filled to BMW's specifications, and the rims are true. Could it be a wheel bearing or wheel balance issue? Driveline, possibly?
Any and all input is appreciated! The car is going to BMW on Wednesday, and I'd like to be armed with the best information possible! Thanks!
Our 1995 540iA has developed a few problems; I'd appreciate everyone's help in trying to diagnose/solve/fix them.
First, a little history: the car was bought a little over a year ago. Single owner (verified), service history, 110k miles. Both the Audi dealer we bought it from (Audi Center Oakville in Oakville, ON) and our BMW dealer ran thorough checks on it last summer and gave it a very clean bill of health (factory spec compression levels, etc.) We drove it 10k miles or so from June-October of last year, and had absolutely no problems with it. No squeaks, rattles, anything.
Since then, we've run into a few minor issues.
1. In early November, we filled the car up with gas -- the same premium 91 octane we always use. Almost immediately, the vehicle ran rich and idled rough. It's smooth once you get going. The M60 isn't down on power, and we seem to be getting around 22-24mpg, which is standard.Our diagnostic tool gave us an O2 sensor code. We've replaced one sensor, but the problem persists. Whether or not our mechanic replaced the wrong sensor, or whether the O2 code was suggesting that something else was up, I'm not sure. I realize there are literally dozens of things that could bring about this problem. What's curious here, however, is that the problem came up almost immediately after filling the car. Is this a case of bad gas, water in the lines, a bad filter....or is it mere coincidence? In any case, the car was store over the winter, and the issue hasn't gone away.
2. While the car was in storage, an unknown fluid leaked out. We think it may be auto transmission fluid, but can't be entirely sure. If that is the case, the 5HP30 doesn't seem to have been affected: it shifts smoothly, doesn't slip, and functions as intended.
3. This issues came up after storing the car over the winter. It wasn't present last fall. While holding a constant speed, a muffled (and sometimes pronounced) vibration noise is emitted (possibly from the back of the car, not sure) at between 50 and 60 mph. Above that it goes away. It also dies off when you accelerated, only come back once you're again holding a speed. The tires are new and filled to BMW's specifications, and the rims are true. Could it be a wheel bearing or wheel balance issue? Driveline, possibly?
Any and all input is appreciated! The car is going to BMW on Wednesday, and I'd like to be armed with the best information possible! Thanks!
