Date:         Mon, 23 Jul 2007 21:23:51 -0400
Reply-To:     Billy Hirt <zbillman@COMCAST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Billy Hirt <zbillman@COMCAST.NET>
Subject:      Re: next question...Re: Is ECU involved in getting power to fuel
              pump when turning ignition switch on?
Comments: To: most david <dmost@yahoo.com>
In-Reply-To:  <113665.62632.qm@web35605.mail.mud.yahoo.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

All that jumper is doing is acknowledging that the fuel pump circuit is good
from the relays to the pump and that the fuel pump itself works.  It could
also tell you that the relay is bad but from what you've stated the relay(s)
were replaced.  I have purchased bad relays before but......

Billy Hirt

On 7/23/07, most david <dmost@yahoo.com> wrote:
>
> I now understand that the ECU provides a ground for the fuel pump relay
> (actually the info provided by Ben explains this on page 4).
>
> Simply removing the fuel pump relay and putting a jumper between pins 30
> and 87 (i.e., closing the fuel pump relay circuit) causes the fuel pump to
> come on.  So, what do I look for next?  Can the jumper provide power to the
> fuel pump while the ECU is not properly grounding the circuit upon turning
> the key?  Or, does the jumper test also mean that the ECU is provding a
> ground?
>
> Thanks,
> David
>
> ----- Original Message ----
> From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
> To: vanagon@GERRY.VANAGON.COM
> Sent: Monday, July 23, 2007 6:18:21 PM
> Subject: Re: Is ECU involved in getting power to fuel pump when turning
> ignition switch on?
>
>
> Take another look. Pin 3 on the ECU operates the fuel pump relay by
> completing the chassis ground. Pin #1 takes a signal from the start
> circuit and the ECU should also operate the fuel pump while the engine is
> cranking. On automatics, this signal is before the neutral safety switch
> so the fuel pump while run when the key is turned to start even if the
> selector in not in neutral or park. Yes, the pump will run without the
> engine actually cranking over.
>
> The pump not turning on when the ignition is switched on is not always a
> failure. It is an ignition pulse that operates it for the short time. The
> pump must run while cranking though. After start, it is the ignition
> pulses that keep the pump on to keep the engine running. Note that power
> for the pump is also the feed for the injectors. A bad hall sensor or coil
> can keep the pump from running along with no spark.
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Benny boy
> Sent: Monday, July 23, 2007 7:26 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Is ECU involved in getting power to fuel pump when turning
> ignition switch on?
>
> No
>
> http://www.loam.org/vw/Vanagon/VanagonProTraining/DigiFant/
> (page 42-43)
>
> I hope the ignition switch was check/replace!
>
> Ben
>
>
>
> On Mon, 23 Jul 2007 14:45:52 -0700, most david <dmost@YAHOO.COM> wrote:
>
> >It's been one month, and I've made no real progress in solving my
> "intermittent power at fuel pump when turning key on" problem in my '87.
>
> At least one person has suggested the ECU (I've ruled out fuel pump relay
> and ignition switch).
>
> For those of you who are good at reading the circuit diagrams in the
> Bentley, can anyone tell me with certainty if the ECU is involved in
> getting
> power to the fuel pump when the key is turned to the on (not start)
> position?
>
> Since I can't use the vanagon now due to not being able to count on it
> starting, I appreciate any help that anyone can offer.
>
> Thanks,
> David
>
>
>
> __________________________________________________________________________
> __________
> Got a little couch potato?
> Check out fun summer activities for kids.
> http://search.yahoo.com/search?fr=oni_on_mail&p=summer+activities+for+kids
> &cs=bz
>
>
>
>
> ____________________________________________________________________________________
> Yahoo! oneSearch: Finally, mobile search
> that gives answers, not web links.
> http://mobile.yahoo.com/mobileweb/onesearch?refer=1ONXIC
>