hey there.
I've not heard of an electronic flea market, tho there may be ones in
Portland once in a while.
all right .......
well, if you see a good one, I'd go $ 200 on one, for sure, and pay shipping
too.
If you make a couple bucks on it, that's fine.
I've used one before on a jet interceptor in the air force.
would be fun to start scoping oxygen sensor output, injector pulse, etc.

I'll check craigslist, thanks.
Scott
----- Original Message -----
From: "David Kao" <dtkao0205@YAHOO.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, October 10, 2008 11:16 PM
Subject: Re: Technical question re: Injector firing signal

> Scott, there are lots of good surplus scopes in electronics flea markets.
> Maybe in Oregon it is harder to come by but here in the Bay Area there
> are always many of them whenever I visit an electronic flea market.
>
> A scope is really a useful tool for checking electrical signals. It is
> probably not too useful on car repairs. Occasionally you may need one
> but maybe once a year? I have two analog scopes made by Tektronics and
> two digital scopes by HP. The digital scopes are far better than old
> analog ones. They are also expensive to get. Analog scopes are very cheap
> nowadays. They are almost all replaced by digital ones. But the analog
> ones are more fun to play with. But it is a difficult tool to use for
> most people.
>
> Sorry, I can not give up my scopes at the moment. Check Craigslist. You
> should be able to find one. I have a Tektronics 485A. It was the top of
> the line Tektronics analog scope 20 yeras ago. It can check signals up
> to 300 MHz. Very cool. I got it for $200 at a surplus store in Sunnyvale
> long time ago.
>
> David
>
>
> --- On Fri, 10/10/08, Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
> wrote:
>
>> From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
>> Subject: Re: Technical question re: Injector firing signal
>> To: vanagon@GERRY.VANAGON.COM
>> Date: Friday, October 10, 2008, 11:49 AM
>> hi.
>> hey, want to sell one of those oscilloscopes !
>> I've been wanting one for ever.
>>
>> For checking for the presence of what I'd call the
>> 'tach signal'
>> ..........at the ECU, I was going to suggest using a
>> tachometer.
>> I know most people don't have 'some tach'
>> laying around .............but
>> that instrument would respond perfectly to what we're
>> looking for.
>>
>> that sure would be an odd coil failure - makes ign. but
>> doesn't send a good
>> enough signal to the ECU.
>> possible of course.
>> I consider coils to be 'nebulous' in that they
>> don't fail black/white
>> generally  - they just get old and funky and weak.
>>
>> have the spark plugs been looked at lately ?
>> if they're dry, and there is high voltage ignition
>> coming out of the coil,
>> and there's fuel pressure, that would tend to indicate
>> the injectors aren't
>> being fired.
>> If they're wet.........then injectors are spraying, of
>> course.
>> Other than the one time I had a wired pulled out of the
>> plug at the Igniter,
>> I've never seen a case where the ECU couldn't tell
>> the engine was turning
>> over.
>>
>> oh.........I'll offer this.  Any time I think I have an
>> intermittent
>> condition at the distributor...........I remove it from the
>> engine, but
>> leave the primary wires still attached, so it's still
>> in the circuit, The
>> turn on the key, and turn the distributor by hand, and rig
>> up a main coil
>> wire so sparks jump to the block,
>> and just see if the dist. will trigger regular fat sparks,
>> over and over.
>>  Last time I had 'it just quit' on an 84 waterboxer
>> ............that's what
>> it was. The distributor would work sometimes, and not
>> others. I just popped
>> on another properly working distributor .......and
>> she's fixed rock solid.
>>  my point is.........if your testing is going to involve
>> the turning of the
>> distributor, rather than cranking on the
>> starter..........remove it and turn
>> it with your fingers........I've just been able to see
>> something that way,
>> that I couldn't by cranking on the starter.
>>
>> all fun,
>> Scott
>>
>>
>> ----- Original Message -----
>> From: "David Kao" <dtkao0205@YAHOO.COM>
>> To: <vanagon@GERRY.VANAGON.COM>
>> Sent: Thursday, October 09, 2008 10:54 PM
>> Subject: Re: Technical question re: Injector firing signal
>>
>>
>> >I should have said oscilloscope, an electronic
>> instrument for
>> > oberserving electronic signals. But this is not
>> feasible for most
>> > people. It is not a common household tool for most
>> people although
>> > I have 4 of them. Two are digital scopes.
>> >
>> > If you attach the red lead of a digital VOM to ECU pin
>> #1 and the
>> > black lead to ground and set the VOM to AC voltage
>> then have someone
>> > crank the engine you can see if you get some AC
>> voltage on the meter.
>> > If you see some strong voltage then the ECU is getting
>> the signal.
>> > Try to test it from outside first. if there is no
>> voltage suggesting
>> > the presence of a signal then there is no point to
>> check it from inside.
>> >
>> > You can check the injectors this way too. Just attach
>> the leads of the
>> > VOM meter to the leads of the injector. The polarity
>> of the leads does
>> > not matter because you are check AC signal. When the
>> engine is cranked
>> > the meter will tell if you are getting a signal. You
>> can use an alalog
>> > meter if you do not have a digital one. Just make sure
>> to set it to
>> > AC volt and start with 20 - 30 volt range. The signal
>> at the ECU pin #1
>> > and the injector signal should be fairly strong to
>> observe this way.
>> >
>> > If you have a spare coil you may want to try it. A bad
>> coil may still
>> > produce some sparks but sends noise to the ECU which
>> will be filtered
>> > out by the ECU leaving no signal to drive the ECU.
>> >
>> > Good luck. Hope the problem is fixed by tomorrow.
>> >
>> > David
>> >
>> >
>> >
>> >
>> > --- On Thu, 10/9/08, B.J.R.
>> <beer_eighty@YAHOO.COM> wrote:
>> >
>> >> From: B.J.R. <beer_eighty@YAHOO.COM>
>> >> Subject: Re: Technical question re: Injector
>> firing signal
>> >> To: vanagon@GERRY.VANAGON.COM
>> >> Date: Thursday, October 9, 2008, 8:50 PM
>> >> I would open the case of the ECU and check pin #1
>> from
>> >> inside
>> >> provided that you have done checking from outside.
>> If you
>> >> have
>> >> a digital VOM you can measure AC voltage on pin #1
>> from
>> >> inside.
>> >> Start from a higher range then switch to lower
>> range until
>> >> you
>> >> get a reading. You should see a few volts up to 10
>> or 15
>> >> volt.
>> >> If it is zero that apparently means trouble there.
>> >> ----IM GONNA GO TRY THAT NOW. SOMETIMES WHEN ONE
>> HAS BEEN
>> >> STUCK ON A PROBLEM FOR A WHILE,
>> >> THE OBVIOUS IS OBSCURED
>> >> If you have a scope it will be the best tool to
>> see the
>> >> signal.
>> >> --A SCOPE???
>> >>
>> >> Check all your ground strips. It could be a
>> grounding
>> >> issue.
>> >> ---REGROUNDED ALL GROUNDS, REAR COMPARTMENT,
>> ENGINE BLOCK,
>> >> TRANNY, BATTERY,
>> >> If you can find an ECU to try it will tell if it
>> is the
>> >> culprit.
>> >> ---IN THAT PROCESS, BUT ILL CHECK ECU #1 FROM
>> INSIDE -OR-
>> >> THE BACK OF THE ECU CLIP FIRST
>> >> Or you can take your ECU to try it on another van.
>> >> HARD TO FIND AN 82 ROUND HERE.
>> >> David
>> >>
>> >>
>> >>
>> >> --- On Thu, 10/9/08, B.J.R.
>> <beer_eighty@YAHOO.COM>
>> >> wrote:
>> >>
>> >> > From: B.J.R. <beer_eighty@YAHOO.COM>
>> >> > Subject: Re: Technical question re: Injector
>> firing
>> >> signal
>> >> > To: vanagon@GERRY.VANAGON.COM
>> >> > Date: Thursday, October 9, 2008, 6:09 PM
>> >> > Here IS A diagram of the system
>> >> >
>> >> >
>> >>
>> http://s417.photobucket.com/albums/pp260/volksproblem/?action=view&current=PA040039.jp
>> >> >
>> >> >
>> >> > I have tested continuity in ecu wires pin #
>> >> > 1, 13, 15, 14, 32, 29, 33, 10,5, 16, 17, 20,
>> 4,
>> >> > Ox sensor
>> >> > 4, 8, 6, 7,
>> >> > ignition control
>> >> > 2, 5, 6, 3, 1, 4
>> >> >
>> >> > All are acceptable range.
>> >> > gave all wires motion to check for loose or
>> weak
>> >> > connections.
>> >> >
>> >> >
>> >> > HOW DO I CHECK FOR SIGNAL FROM IG COIL TO ECU
>> #1 ???
>> >> >
>> >> >
>> >> >
>> >> >
>> >> > ----- Original Message ----
>> >> > From: Scott Daniel - Turbovans
>> >> > <scottdaniel@turbovans.com>
>> >> > To: B.J.R. <beer_eighty@YAHOO.COM>;
>> >> > vanagon@GERRY.VANAGON.COM
>> >> > Sent: Thursday, October 9, 2008 5:57:33 PM
>> >> > Subject: Re:      Re: Technical question re:
>> Injector
>> >> > firing signal
>> >> >
>> >> > do you know how to check continuity with a
>> volt-ohm
>> >> meter ?
>> >> > essential to checking wiring harness
>> continuity.
>> >> > the less expensive ones, analogue, start at
>> under 5
>> >> > dollars- made in china
>> >> > of course.
>> >> > Digital volt-ohm meters, which are far more
>> >> > capable.......like for checking
>> >> > oxygen sensor output .......
>> >> > cost more of course.  Recently my 20 year old
>> one died
>> >> -
>> >> > Radio Shack's best
>> >> > one was 70 bucks I think.
>> >> > Scott