Re: e28 M5 acceleration issues...

[GRobWorkII@xxxxxxx]

James,

   I would suspect the throttle position switch.  The fact that you aren't 
getting the hesitation at full throttle suggests that the switch is bad - it 
reads three things:  idle, between 1 and 99% (middle ground), and WOT (wide 
open throttle).  My guess is that the "middle ground" contact is shaky.

Hope this helps,

RobW

In a message dated 8/27/00 10:10:10 PM Eastern Daylight Time, 
owner-bmw-digest@domain.elided writes:

> Date: Sun, 27 Aug 2000 18:53:21 -0700
>  From: "James Nelson" <xi@domain.elided>
>  Subject:

>  
>  Hi! My 1988 M5 exhibits fairly odd acceleration behavior---it can best be
>  described as a hesitation, and occurs mostly (always?) between 1% and 99%
>  throttle. It's almost as if the car can't make up its mind if it wants to 
go 
> or
>  not. Once I put the pedal down completely, however, there isn't much 
> hesitation,
>  if any.
>  
>  I bought the car in April, and previous to that it was in storage. It 
> underwent
>  a thorough check-up (including hoses/belts/cat/etc. replacement) at the 
> local
>  BMW specialist, it passes smog, and otherwise drives fine. Swapping 
between 
> the
>  JimC and BMW chips does not seem to make any difference in this arena. I've
>  heard that vane-type airflow meters can cause a similar behavior, is this 
> true?
>  Or is there a way I can determine if my AFM is actually on its way out? Is 
> this
>  a common problem on e28 M5's?
>  
>  One other data point---it does not seem to accelerate as fast as I would 
> have
>  thought. Our '89 750 keeps-up quite nicely with it, with such close HP 
> numbers
>  (299 & 294) it would seem the e28 would win by a significant margin (given 
> the
>  weight/transmission). The e32 can't quite corner the same, though. :-)
>  
>  TIA,
>  
>  James Nelson...
>  1989 750iL
>  1988 M5
>  1975 2002

------------------------------