fuel pump keeps running! - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Electrical
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 09-11-2009, 02:13 PM
Registered User
 
Join Date: Apr 2007
Location: uk
Posts: 5
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
fuel pump keeps running!

Hi
I've got a 1992 305 TPI Chevy engine running a S&P harness in a hotrod. Recently, when I turn off the motor, the fuel pump keeps running on & on & on. I've had to disconnect the battery to stop it. Reconnecting the battery seems to reset it. I did disconnect the fuel pump relay - but it still stayed on. However when I disconnected the oil pressure switch it stopped. Any ideas whats happening???

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 09-11-2009, 03:01 PM
SSedan64's Avatar
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Macon, GA.
Age: 50
Posts: 6,016
Wiki Edits: 0

Thanks: 0
Thanked 46 Times in 46 Posts
Bad pressure switch or incorrect wiring. Does pressure switch supply ground or 12V?
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 09-12-2009, 09:35 AM
Registered User
 
Last wiki edit: Wheelbase database Last photo:
Join Date: Jan 2007
Location: Virginia
Posts: 3,593
Wiki Edits: 1

Thanks: 6
Thanked 159 Times in 146 Posts
Not sure about the aftermarket harness, but the stock harness uses two methods to power the pump. There is a relay controlled by the computer that switches the pump on for two seconds when you first turn the key to START to prime the fuel system. The oil pressure switch is wired in parallel to this relay and takes over once the engine starts. Both provide +12v to the pump. Either one could be bad and cause the pump to stay running.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 09-18-2009, 11:38 AM
Rustydawg's Avatar
Cruzin w/Elvis in Bigfoots UFO
 
Last photo:
Join Date: Nov 2004
Location: Edmonton AB, Great White North
Age: 49
Posts: 248
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Sounds like the contacts within the oil pressure switch are 'welding' together slightly. The factory switches are pretty heavy duty to handle the full current of the fuel pump, are you using a larger fuel pump, or is the oil pressure switch not a factory one made to switch larger currents (other than turning a dash light on)?
Reply With Quote Quick reply to this message

Recent Electrical posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
acceleration flat spot in carb. corvettetonybone Engine 17 04-13-2013 08:31 PM
Jet Boat Fuel Pump Question(s) ezobens Engine 22 09-02-2009 09:52 AM
87 Suburban fuel pump help needed Mustangsaly Engine 14 10-29-2007 09:04 AM
Help - my fuel pump is leaking KENMO Engine 10 07-01-2007 12:39 PM
Carb size to small???? brainsboy Engine 50 08-14-2005 04:04 PM


All times are GMT -6. The time now is 06:01 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.