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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
Comments: To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
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&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 > >


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