Re: E28: Rough running above 2000 RPM **Rob

["Rob Levinson" <always_coca-cola@xxxxxxx>]

Andy Sparks ( ASparks106@domain.elided ) wrote:

>Subject: E28: Rough running above 2000 RPM
>
>I have an '82 528e that I have been wrestling with for several weeks now
and
>am in need of ideas.  I presently have the car at a very reputable BMW
repair
>only shop in Augusta, GA and they are also stumped.
>The symptoms: Starts fine, idles fine, runs great up to 2000 rpm, then cuts
>out and has basically no power.  Gas mileage is awful.
>What we have examined so far: Fuel pressure and flow rate - OK. Coil,
plugs,
>wires, condensor, rotor - Checked all OK.  Air mass flow meter - put in
good
>one to test - No improvement.  Motronic brain - put in a good one to test -
no
>improvement.  Fuel injectors - put in good ones to try - no improvement.
>Vacuum leaks - None.  Catalytic convertor - checked but not stopped up.  O2
>sensor - Checked OK.  Speed sensor and TDC sensor - checked OK, but could
be
>going bad at higher rpm; will replace next and then try.  Throttle switch -
>checked OK.
>HELP!  What else could be the problem?  I have pretty much run out of
options.


            You could have something that only occurs when the engine is
under load (or caused by the different vibration of an engine under load).
Even though youe E28's motor is completely different than mine, everything
is similar.  A few things that spring to mind:

1) "invisible" crack in a vacuum line or on the underside of the plasic
intake tube.

2) loose fuel injector electrical connector (took me a month to find that on
mine!) - it may look snapped in but could just be making enough contact to
idle well... the connection loosens at higher rpm.

3) Even though the cap and rotor may look okay, they could be bad anyway.
It's a semi-expensive test (about $80), but it certainly couldn't hurt to
swap them.

    Good luck!

- - Rob Levinson
'85 535i Turbo

www.shortshifter.com

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