

| Subject: | Re: Is ECU involved in getting power to fuel pump when turning ignition switch on? |
| From: | Dennis Haynes |
| Date: | Mon, 23 Jul 2007 20:18:21 -0400 |
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
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