RE:<E28> Need Diagnostic Help.. 535i running rough

["Shaun Dustin" <sdustin@xxxxxxxxxxxxxx>]

Ron,

Sounds suspiciously like maybe a fuel filter (best case), or a fuel pump,
but I would be inclined to replace the filter first. A crapped up fuel
filter will do what you describe, and although I'm not familiar with the
e-28 per se, I've felt similar symptoms in old VWs, pickups, and my '91
e-30. Comes from bad gas (we get a lot of that in rural Idaho), running your
tank too low (fillup will suspend sediment on the bottom of the tank), etc.
Unless someone else comes up with a better answer, I'd replace it and see
what happens. A bad filter will stress your fuel pump by raising system
pressure between the filter and the pump, and accelerate wear on the pump.
It can also cause your engine to run lean, unless BMWs have electronices to
prevent that???. On old VWs, it usually ends up meaning a burnt valve in my
experience.


Shaun Dustin, PE
Intrepid Technology and Resources
501 West Broadway
Ste 200
Idaho Falls, ID 83402
208-529-5337
www.intrepid21.com