Date: Sat, 11 Oct 2008 04:49:15 -0700
Reply-To: mdrillock <mdrillock@COX.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: mdrillock <mdrillock@COX.NET>
Subject: Re: Technical question re: Injector firing signal
In-Reply-To: <193601c92b6b$be23c4c0$6701a8c0@PROSPERITY>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Here you go Scott. Plenty for simple automotive use.
http://sfbay.craigslist.org/sby/sys/873977808.html
I mostly use mine for oxygen sensor testing but it sometimes helps me
with other problems. Yesterday I found a bad idle control unit with it.
Mark
Scott Daniel - Turbovans wrote:
> 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¤t=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
>
>
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