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5418RE: [bmw e28] Re: 83 528E converting the car from automatic to manual 5 speed

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  • Jeff Schlenker
    Aug 17, 2010
      " Could a bad controller cause the timing symptoms I an experiencing?"
      Absolutely!



      My Bentley says that the Motronic 1.0 uses two sensors (pointed towards the
      flywheel) and the 1.1 uses one. BMW may have used two different flywheels
      one for the 1.0 and a different one for the 1.1 system. My guess is that the
      two would be incompatible. Probably put the "tit" in a different place. I
      know that on a 1.0 system the "tit" indicates TDC. They may have moved the
      "tit" on the 1.1 to dial in some static timing. The composition of the "tit"
      may be different (i.e. a stronger magnet). I can tell you that the newer
      Hall Effect Cam sensors are sensitive to magnetic polarity. Most want the
      North pole pointed towards the sensor. If you sweep the South pole past the
      sensor it yields a real noisy pulse as opposed to a nice clean spike. An
      ignition coil whose dielectric has or is breaking down will give a miss and
      a pop. If you have access to a dual trace O-scope you could compare the
      flywheel sensor output to the diagnostic timing sensor that's mounted on the
      front of the motor. The front sensor isn't used for engine operation as it's
      output dead ends at the diagnostic connector.



      Anyway I'd make sure that the sensors/ECU/flywheel all came off the same
      motor. If the bell housing was off a 1.1 system and the sensors/ECU are 1.0,
      BMW might have relocated the sensor hole, rotationally and depth wise. The
      Motronic 1.0 and 1.1 make a lot of assumptions in their programming as they
      are a pretty stupid embedded controller/comparator.





      From: bmwe28@... [mailto:bmwe28@...] On Behalf
      Of elswwjd316
      Sent: Tuesday, August 17, 2010 3:11 PM
      To: bmwe28@...
      Subject: [bmw e28] Re: 83 528E converting the car from automatic to manual 5
      speed





      Jeff,

      Thanks for the reply. According to the shop owner who tested the car, the
      flywheel has a raised "tab" or "tooth" that the TDC sensor "reads" and the
      flywheel we have in the car has two such sensor points on it's perimeter;
      the first is in the wrong position and the second is causing the backfiring
      by causing a false signal. He and his mechanic found a mechanic in Australia
      who had the same problems after a conversion to an identical car. That
      mechanic said that there are different fly wheels for each of the two fuel
      injection controllers used that year, version 1.0 and 1.1 Motronic ignition.

      I have tried three controllers: the original burned out. The second was an
      exact used replacement and it is in the car now. The third was dead on
      arrival. Could a bad controller cause the timing symptoms I an experiencing?

      I am now trying to do two things: first, find out if this is true (two
      flywheel models) and if so to find the other flywheel used somewhere. I have
      the official BMW shop manual and it does not mention two flywheels, although
      it does list both versions of controllers.

      Another point is the shielding on the sensor cables. Since these are for
      signal voltage only, the ground shield is only attached to the controller
      case ground though the main cable. I had the shop replace both sensors with
      brand new because the old sensors were showing lots of electrical noise.

      BTW, the car ran perfectly before the conversion was begun except for minor
      overheating which I fixed by replacing the radiator and water pump. The car
      has 102,000 original miles on it and drove like a new car when I bought it 3
      years ago. My son, who is now driving, is working with me on this trying to
      get the car drivble for him to use it for school.

      All suggestions and help is greatly appreciated.

      Regards,

      Ed Stodghill
      lone.antelope.ranch@... <mailto:lone.antelope.ranch%40gmail.com>

      --- In bmwe28@... <mailto:bmwe28%40yahoogroups.co.uk> , "Jeff
      Schlenker" <jeffreyl_56655@...> wrote:
      >
      > The fact that it runs means the TDC sensor is functional. Either the
      engine
      > speed sensor is bad or the wiring is bad, or that pin on the computer is
      > fried, or that circuitry in the computer internally is toast . Those
      cables
      > (TDC & engine RPM) are shielded because the signals that traverse them are
      > itty-bitty electrically. There is a lot of stray electrical interference
      > (coil & spark plug wires most notably) in the engine compartment. Scrape
      the
      > cable and the computer will get false readings. The distance the sensors
      are
      > from the flywheel is also critical. Closer is better. The engine block
      must
      > have a good ground and share the same ground as the shielding on the
      sensor
      > wiring. I have several of these older BMW's and the first thing I do when
      I
      > get one is re-do all the ground wiring. This clears up 90% of all the
      > electrical gremlins. Spark advance is determined by engine speed (no
      advance
      > = low power). The start of spark timing is determined from TDC sensor
      > (backfire = unreliable TDC signal). A sloppy worn out timing belt will
      cause
      > performance issues as the distributor is driven off the cam.
      >
      >
      >
      > From: bmwe28@... <mailto:bmwe28%40yahoogroups.co.uk>
      [mailto:bmwe28@... <mailto:bmwe28%40yahoogroups.co.uk> ] On
      Behalf
      > Of Gil Thereault
      > Sent: Monday, August 16, 2010 8:15 PM
      > To: bmwe28@... <mailto:bmwe28%40yahoogroups.co.uk>
      > Subject: Re: [bmw e28] 83 528E converting the car from automatic to manual
      5
      > speed
      >
      >
      >
      >
      >
      > This may sound stupid. The first thing come to mind the automatic trans
      has
      > a separate computer that is still hooked up?? Unless one of the two
      sensors
      > are bad. Swapping out these may also rule out things.
      >
      > --- On Mon, 8/16/10, elswwjd316 <lone.antelope.ranch@...
      <mailto:lone.antelope.ranch@...%0b>
      > <mailto:lone.antelope.ranch%40gmail.com> > wrote:
      >
      > From: elswwjd316 <lone.antelope.ranch@...
      <mailto:lone.antelope.ranch@...%0b>
      > <mailto:lone.antelope.ranch%40gmail.com> >
      > Subject: [bmw e28] 83 528E
      > To: bmwe28@... <mailto:bmwe28%40yahoogroups.co.uk>
      <mailto:bmwe28%40yahoogroups.co.uk>
      > Date: Monday, August 16, 2010, 1:36 PM
      >
      > Have completed converting the car from automatic to manual 5 speed.
      Ignition
      > timing is still off after replacing both sensors on bell housing and
      having
      > them set by a shop. Low power, hard starting and occasional backfire.....
      >
      > ------------------------------------
      >
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