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Date:         Tue, 23 Mar 2010 20:54:43 -0700
Reply-To:     Gerald Masar <azsun99@EARTHLINK.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Gerald Masar <azsun99@EARTHLINK.NET>
Subject:      Re: Cranks but now, STARTS!
Comments: To: mark drillock <mdrillock@COX.NET>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
              reply-type=response

Thanks Mark and David, But the '88 has the older TA ECU 025906022. On the other hand, in trying to sort out the original problem, I was checking grounds behind the main fuse and relay panel and found a blue-green wire with a sort of squarish, white connector on the end, not connected to anything and not looking like it would fit into any of the existing connectors. So, the mystery deepens, but in the meantime, I guess I will order the correct relay which seems to be about $28.00! The NAPA made in China one was $9.00. And I will keep an eye open for "smoke signals". Jerry

----- Original Message ----- From: "mark drillock" <mdrillock@COX.NET> To: <vanagon@GERRY.VANAGON.COM> Sent: Tuesday, March 23, 2010 8:10 PM Subject: Re: Cranks but now, STARTS!

> It's mostly a WAG, but I think the purpose of the diode providing key on > power to the extra ECU pin is to power up some OBD logic inside the 022D > version of the ECU. This power would thus get there even if the ECU > power relay failed and there may even be a fault code generated to tell > that the relay had failed. This support for an OBD capability was short > lived and I'm not certain it was ever fully implemented though I have > seen claims that it was. The 88/89 wiring diagram shows a switch and led > to read fault codes though my old 88 did not have it. Some 88 and/or 89 > apparently did have this on the dash or the special relay. I would like > to examine Jerry's van since he has the special relay and I wonder if he > also has the switch and led. > > Mark > > David Beierl wrote: >> Dear Jerry, >> >> At 08:26 PM 3/23/2010, Gerald Masar wrote: >>> The diagram on the VW relay has 87A connected to the same line as >>> 86, but with a symbol that looks like a diode. >> >> Because it is a diode. :-) Looking on 97.206, current tracks 36 and >> 37, let's see if we can figure it out: >> >> a) At the relay terminals: >> Both terminals 4/86 and 5/15 will actuate the relay if they receive >> +12v. If it's 86 that gets the voltage that's all that will >> happen. The other terminal will not have voltage on it. OTOH if >> it's 5/15/87A that is energized, two things will happen. The coil >> will actuate and there will also be 12 v on terminal 86, driving some >> device(s) back up the wiring somewhere. >> >> b) In the larger circuit: >> Relay terminal 86 is driven from pin 23 of the ECU at track 23 >> (coincidence). It connects to nothing else; so when pin 23 goes >> active the ECU relay actuates but nothing else happens. >> >> Relay terminal 5/15/87A is connected to the + terminal of the >> ignition coil and various other places and that whole two-relay + ECU >> circuit makes my head spin. >> >> So I'll just say that VW put that diode in there intentionally, and >> if it's left out *something* in the ECU/fuel system is going to work >> differently than before, and in that sense it's broken. There also >> may be loss of the magic smoke from some component(s), so all in all >> I'd stick with the diode until the day may come when you know exactly >> what effects that change would make. If I happen to figure it out >> I'll let you know. <g> >> >> Yours, >> David >>


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