Date: Sat, 11 Oct 2008 07:21:53 -0500
Reply-To: Larry Alofs <lalofs@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Larry Alofs <lalofs@GMAIL.COM>
Subject: Re: Technical question re: Injector firing signal
In-Reply-To: <48F092BB.4060801@cox.net>
Content-Type: text/plain; charset=ISO-8859-1
So, describe your procedure yesterday, what you looked for, what you saw,
etc.
I most often use mine on O2 sensors too. High impedance and responds
quickly; hard to get both features in a meter.
Larry A.
On Sat, Oct 11, 2008 at 6:49 AM, mdrillock <mdrillock@cox.net> wrote:
> 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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