Date:         Mon, 23 Jul 2007 20:18:21 -0400
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
Comments:     RFC822 error: <W> MESSAGE-ID field duplicated. Last occurrence
              was retained.
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Re: Is ECU involved in getting power to fuel pump when turning
              ignition switch on?
Comments: To: Benny boy <huotb@VIDEOTRON.CA>
In-Reply-To:  <vanagon%2007072319282295@GERRY.VANAGON.COM>
Content-Type: text/plain; charset="us-ascii"

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