Need help, engine cutting out at 3000 rpm (ctxt)

d_russian · 14th November 2004, 20:15

Maybe somone has experienced this or knows what the problem might be. The local BMW tech cant figure it out. Has called Tech line.

I will try to be as descriptive as I can.

The car is a 2001 M5. If I take the car up to 6K RPM (not hitting the rev limiter) in third gear, upon shifting to 4th gear, there is absolutely no power when I depress the gas pedal. I can floor the gas pedal but nothing happens. It is if the engine is not putting out at all. The rpms do not drop to idle, the rpms stay up. The car decelerates. Below 3K rpm I can get very little power (perhaps 1/3 of normal) but the engine feels smooth, just very weak. As I approach 3K rpm (from 2K) in any gear the car starts "bucking" right at 3 K rpm. The sensation is not dissimilar to what one experiences as one hits the rev limiter. I pull over and turn the car off. I restart the car. The car drives fine. Pulls fine. No problem until I hit approx 6K rpm in third gear. Then the same thing happens. The engine will attempt to cut out at approx 3K rpm no matter what gear I am in. BTW, no error light or warning lights come on.

The BMW tech drives the car with me. This scenario occurs 3 out 6 times. So it is intermittent. Sometimes the car will continue to drive fine after 6K rpm in 3rd gear and sometimes not.

The tech ran a scan. The errors that came up were that 1st cylinder was misfiring and something regarding fuel pressure. So I am thinking that perhaps it is a fuel pump or somesuch but he tells me that it is not likely to be so simple. He says that the errors could be the symptoms of something else.

I dont know. I am open to suggestions. Anyone have an idea ?
Thanks in advance.
d_russian

Digi · 14th November 2004, 22:42

I'd guess there is not enough fuel, and fuel pump, or some other reason for intermittently not getting enough fuel seems likely. Like the tech says, the answer may not be easy to find. Funny that there is nothing much in the computer that helps identify the problem.

Ahmed · 15th November 2004, 12:37

many possibilities, however the scan should give you an idea of where the problem may lye.

have them check your MAF's sensors fitst. If that doesnt work, then probably the CAM positioning sensors ( either intake or exhaust ) maybe be faulty.

Also, you say its intermitent, have them check your throttle potentiometer.