RE: Intermittent miss '92 535i 5sp

[Land Shark <lndshrk@xxxxxxxxxxxx>]

Jon Brush writes:

>Several of us E34 535iers have had the following problem without solution:
>while tooling along at part throttle (almost trailing throttle), and low
>rpms, hit a sharp bump. 1-2 sec later, the engine will miss, then continue
>running as before. This is a *very* intermittent problem, at least in my
>car; I can drive for a week without noticing anything, even over the same
>bumps on my daily commute, then may experience the problem one or two times
>the same day, then again a long interval. Several attempts to find the
>fault have revealed no codes in the computer, and one mechanic with an
>expensive diagnostic machine hooked up to the car's electronic brain found
>no faults while driving around for a while. 

 Jon, I refer you/your technician to SI 12 09 91 (3413), dated March 1992

 To summarize, 1991 and early 92 535i and 735i's w/ ASC, as well as 89/90 750il's
 and all 850iA's produced prior to 7/91 that are equipped with ASC modules of
 one of these 3 part numbers:

 34 52 1 159 246
 34 52 1 159 491
 34 52 1 160 025

 Vehicle miss occurs:
 
 1) Around 45-60 mph
 2) on a rough surface (tracks/speed bumps/etc)
 3) Light (approx 1/8th) throttle
 4) ASC not switched off

 If this is you.. symptoms and ASC part number..

 You need to replace your ASC control unit

 With part # (this is for 535i only, others are listed in the bulletin!)

 34 52 1 090 155  New
 34 52 9 064 437  Reman.

 Hope this helps..

 Jim

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