Re: bmw-digest V9 #2244

[Demian Trubey <trubey@xxxxxxxxxxxxx>]

The DME has "forgotten" it's stored fuel/spark maps and will have to
relearn.   After a run around town your car will run right I am confident.
I have a friend with an e28 535i which does the same thing  takes a 20
minute drive to straighten things out.   Please, help from the audience on
this one... I seem to remember learning that this initial run-in period with
only default values stored is the best time to "train" the DME into it's
maximum output state.  Or maybe I've just been hitting the crack pipe too
hard???  Either way the primary reason for an engine to run "rough"
(missing, sputtering, idling slow/rough, etc...)is a spark condition.   A
valve condition of course could cause this as well but that would manifest
very slowly (probably).  Valve condition would be checked by a compression
gauge.   Remedy spark issues by only a handful of things:
1. DME
2. Supply clean  current: new plugs, wires, cap, etc...
3. Wiring issues, particularly ground resistance going to the block and
engine electronics
4. Add more bass.   Bass can help any rough running car.  Bass is the
automotive equivalent to the ventromedial hypothalamus.
Trubey
'79 528i 3.5/5
'84 323i Baur M52TU
Plus other assorted non-BMW daily driver type of stuff...


> Date: Fri, 20 Sep 2002 15:39:27 -0400
> From: Terry Peterson <tpeterson99@domain.elided>
> Subject: 86 535i (E28) Running Rough
>
> I have an '86 535i that started running rough after the
> battery was disconnected and then reconnected again.
> This has happened to me twice in the past 2 months.
>
> The first time I removed the battery to try it in a friends
> E28 that had a dead battery.
> After I put it back in my car, It ran very roughly when I
> started it and I had to keep my foot on the gas to keep it
> running.  After a few minutes of this it smoothed out and
> ran fine.
>
> Last week I disconnected the battery so I could remove the
> instrument cluster to replace the service indicator batteries.  When I
reconnected the battery and started the
> car it ran very rough and I had to keep my foot on the gas to keep it
running.  It runs rough at idle and at higher rpms and it still runs bad
after it warms up.
>
> I checked for vacuum leaks, I checked all of the electrical
> grounding and I checked the idle control valve and found no
> problems.  Does anyone have an idea what this could be?
>
> Thanks,
>
> Terry Peterson

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