Date: Fri, 10 Oct 2008 11:49:01 -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: Technical question re: Injector firing signal
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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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