Date:         Thu, 24 Mar 2011 13:43:43 -0700
Reply-To:     Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject:      Re: Engine analyzer/tach recco?
Comments: To: camping.elliott@gmail.com
Content-Type: text/plain; charset="utf-8"

hi ..
yes...there could be some other factor as 'normally/supposedly it shouldn't drift anywhere by itself as you say. 

so perhaps something ..
air leak, an injector spray pattern not so good ..
or 'something' ...

I will also say that waterboxers do not especially hold a 'set up' that well. ..

about the only thing that wears much ...
tiniest bit of wear on spark plug electrode gaps ..not enough to even matter...
I almost never put in new spark plugs on my own vanagons as I have about 40 bosch spark plugs with 80 % of their life left in them easily...they hardly wear, and the ignition is really strong. 
plug wires get old, very, very gradually..

throttle bodies ..being so old...are always a bit suspect .

generally ...my waterboxer engines hold and keep a tune-up and 'set up' of the fuel injection pretty well...
like a year with no changes in idle etc...
but I see them get 'off' some all the time on many vanagons. 

air flow meters wear too...always a weak area.
and air leaks ..can't say that one enough. Can't have any. 
I have found up to 10 air leaks between the where the throttle body screws onto the plenum ..
and the intake ports. - on one engine.

I'd check compression too.
Typically I find an exhaust valve or two leaking a little .
and the hyd lifters should not get out of adjustment ..
but once in a while .....maybe those should be checked ..
but check compression first...it's easy, and it's valuable information. 

there was recently a post giving a link to adjusting the mixture screw on the air flow meter..
it was quite good..
semi-involved procedure reading oxygen sensor out put ....adjusting to a particular voltage , etc. 

if you turn that allen screw ..
keep track of where it was so you can get back there if you need to. 

Scott

  ----- Original Message ----- 
  From: Rocket J Squirrel 
  To: Scott Daniel - Turbovans 
  Cc: vanagon@GERRY.VANAGON.COM 
  Sent: Thursday, March 24, 2011 12:15 PM
  Subject: Re: Engine analyzer/tach recco?


  Hi Scott,

  There are plenty of cheap ones on the market, but I was looking for a recommendation for one that's reasonably accurate and has a dedicated 4-cyl setting. Just looking for the experienced answers. 

  The air bypass screw on the TB fixed the high idle, but it had to be turned in a number of turns. Why, I don't know. Now the idle is nice and low and does not surge. I'll have to poke around and see if I can find out why the adjustment even needed to be made because it should not have drifted that high by itself. 

  On Thu, 2011-03-24 at 10:04 -0700, Scott Daniel - Turbovans wrote:

     
    HI.. 
    did you search online .......like at discount auto parts or tool stores ? 
    I'd think one can still buy a dwell/tach meter.  
     
    you tried turning in the air bypass screw on the throttle body ? 
    and you've checked very carefully for air intake leaks ? 
     
    and there is a bit of free play in the throttle cable ? 
      ----- Original Message ----- 
      From: Rocket J Squirrel 
      To: Scott Daniel - Turbovans 
      Cc: vanagon@GERRY.VANAGON.COM 
      Sent: Thursday, March 24, 2011 7:59 AM 
      Subject: Re: Engine analyzer/tach recco? 






           
      On Thu, 2011-03-24 at 00:16 -0700, Scott Daniel - Turbovans wrote: 

hi ...
not sure what you mean by 'engine analyzer ...
that used to mean a tach/dwell meter I believe.

you don't need a dwell meter with electronic ignition of course.
as for a tachometer...
if it's about adjusting idle rpm say ..
not really important to have I'd say.

      Thanks, Scott -- I wasn't sure what those tach/dwell meters were called, and didn't want to just write "tachometer" because folk might think I was looking for something to mount on the dash. 

      I have a digital tach which clips to the coil's green wire, but my recent (mis) adventure with surging idle got me irritated with it again. My old analog meter had no trouble tracking uneven idle, but this digital one can't keep up.

      In my electronics work, I use digital meters to measure voltages and currents which are not moving rapidly, but there are times when a good old electromechanical movement gives a better picture. Finding myself in that position here, I thought maybe tach/dwell meters were still available. 

      I gather they are not?

-- 
Rocky J Squirrel