

| Subject: | Re: Technical question re: Injector firing signal |
| From: | Larry Alofs |
| Date: | Sat, 11 Oct 2008 07:21:53 -0500 |
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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