hi.
lol...it says 83 AIR-COOLED right there in the first line..
first few words even ! .. my bad. 

that's a good thought about the ecu not being able to see the ignition pulse from the new electronic ign.
good thinkin' ....could be possible I supposse.

what coil does it have currently ? 
the old one with 25 years on it ? 
if it's not   the correct type coil for your new ign system I'd be suspecious of that part ..
and when they are 'just very old' ..
I don't trust coils very too much if there are weird issues. 

I fixed one points-fired vanagon one time by replacing the coil.
it was an inline four gas engine ..with points..
sitting idling it would just 'shut off'.
coil was really old.
I put on a new one, or another better used one ....
that fixed it. 

since ignition is 'the thing' you changed..
naturally that's where your focus would go of course. 

is there a lot of shaft side-play in the distributor ? 

does it do it no load,
or just under load ?

is there a crack in the air intake boot and engine torque at 3K rpm is pulling it open ? 

scott 
turbovans

  ----- Original Message ----- 
  From: Jonathan Poole 
  To: Scott Daniel - Turbovans 
  Cc: vanagon@gerry.vanagon.com 
  Sent: Wednesday, April 13, 2011 3:50 PM
  Subject: Re: Consistent cutout at 3k rpm

  Hey Scott,

  It's also pretty common for folks to not read what is written,, check again and you'll see that my first sentence provides year and engine information ;)

  Thanks for your suggestion and I agree that it could be the afm.  I did pop the cover off, lightly clean and even adjust the slider to see if it was related to this issue.  I have a real-time air fuel ratio guage so can make adjustments like this and get the ratio dialed back in although I'm waiting for a replacement part on it currently so am set by ear/temp until it comes back in.  In any case it doesn't appear to be slider wear in the afm.  I've been wondering if it is the signal coming from the pertonix that is not up to keeping the injectors firing at higher rpm.  It's like there is still a signal at the dizzy but maybe the computer loses it?

  Jonathan

  On Wed, Apr 13, 2011 at 4:49 PM, Scott Daniel - Turbovans <scottdaniel@turbovans.com> wrote:

    lol..
    half the time people don't say what kind of engine they are talking about.

    since all waterboxers have electronic ignition ( waterboxer starts in 1983 ) and 83 diesels don't have points , you must be talking about an air-cooled vanagon.

    it's really nice to have two distributors ..
    one to modify, one stock with points as a back up.
     I think I would look for another good used distributor just to have one anyway.

    Air flow meter pops into my mind.
    I have seen them get worn in one spot ..
    the spot that corresponds to around 3,000 rpm .

    just a thought of something else to consider..
    not a real diagnosis.

    what happens if you just advance the timing more ?
    just as a test.

    ----- Original Message ----- From: "Jonathan Poole" <jfpoolio@GMAIL.COM>
    To: <vanagon@GERRY.VANAGON.COM>
    Sent: Tuesday, April 12, 2011 9:33 PM
    Subject: Consistent cutout at 3k rpm

      Howdy Vanagon List,

      My '83 Air-Cooled Vanagon is consistently cutting out at 3 thousand rpm.
      This behavior started recently after I made some changes to the ignition
      system.  I believe that the problem is related to my changing out the
      breaker points for a pertronix electronic ignition module but it may also be
      related to the new plug wires, distributor cap, rotor, coil, plugs or the
      thorough cleaning of all accessible electrical connections in the engine
      compartment or the adjusted timing.

      A few items of note:
      -the timing at idle and high-rpm is good (7.5 deg to 31 deg) so it doesn't
      appear to be an advance issue
      -the engine runs great all the way up to 3k rpm with better power/feel than
      before these changes
      -fuel pressure was stable when tested it while making these changes.
      -engine temps are good (350 cht, < 220 oil) when cruising at 2900 rpm
      -I have tried different gaps between the pertonix unit and the magnetic ring
      with little/no change in cutout/performance.
      -the tach doesn't drop or jump erratically when the engine cuts out which
      may contradict my suspicion of the pertronix unit?  The tach is out of a '91
      Vanagon and wired up in typical fashion off of the coil.

      My next tests will be to re-check voltage at the coil at high-rpm and then
      to put the points back in but I wanted to inquire here before the switch-out
      in case there is something easy that I have overlooked that I can test
      before pulling the pertronix out.

      Any suggestions, especially of easy tests, are appreciated.

      Thanks,

      Jonathan