Measuring Fuel Pressure - 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> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 06-18-2003, 08:49 PM
New Member
 
Join Date: Nov 2002
Location: Australia
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Measuring Fuel Pressure

Hey all,

I have a 350 chev with a 650 cfm Holley carb and a stock mechanical fuel pump. I have measured the fuel pressure and got a reading of 10psi, so I went and installed a Holley fuel pressure regulator, which is pre-set to 7psi (well at least thats what the instructions say) and I have taken another measurement but I get the same reading.

Now my question is what is the correct method for measuring fuel pressure?

Currently I am letting the engine warm up which ensures the fuel bowl is full. I turn off the engine, disconnect the fuel line from the carby and insert a pressure gauge into the fuel line at the position where it normally connects to the carby. Restart the engine and leave for 10 - 20 secs. Is this the correct method, how long should you take the measurement for?

Any help would be greatly appreciated.

Waterhead.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-18-2003, 08:59 PM
WV hillbilly
 

Last journal entry: PTL 220CC
Last photo:
Join Date: Jun 2003
Location: WV
Age: 39
Posts: 784
Wiki Edits: 0

Thanks: 1
Thanked 2 Times in 2 Posts
Re: Measuring Fuel Pressure

Quote:
Originally posted by Waterhead
Hey all,

I have a 350 chev with a 650 cfm Holley carb and a stock mechanical fuel pump. I have measured the fuel pressure and got a reading of 10psi, so I went and installed a Holley fuel pressure regulator, which is pre-set to 7psi (well at least thats what the instructions say) and I have taken another measurement but I get the same reading.

Now my question is what is the correct method for measuring fuel pressure?

Currently I am letting the engine warm up which ensures the fuel bowl is full. I turn off the engine, disconnect the fuel line from the carby and insert a pressure gauge into the fuel line at the position where it normally connects to the carby. Restart the engine and leave for 10 - 20 secs. Is this the correct method, how long should you take the measurement for?

Any help would be greatly appreciated.

Waterhead.
if you have an in line fuel filter (between the fuel pump and carb) you need to check the pressure after the filter...
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-18-2003, 09:09 PM
New Member
 
Join Date: Nov 2002
Location: Australia
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have been taking the measurement from the end of the hose that connects to the carby ie. after fuel pump, filter and regulator.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-18-2003, 09:11 PM
WV hillbilly
 

Last journal entry: PTL 220CC
Last photo:
Join Date: Jun 2003
Location: WV
Age: 39
Posts: 784
Wiki Edits: 0

Thanks: 1
Thanked 2 Times in 2 Posts
Quote:
Originally posted by Waterhead
I have been taking the measurement from the end of the hose that connects to the carby ie. after fuel pump, filter and regulator.


have you tried to adjust the regulator?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-18-2003, 11:54 PM
New Member
 
Join Date: Nov 2002
Location: Australia
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
No, not as yet as I wanted to make sure I was testing the pressure right first. No point going and changing the regulator if its not the regulator.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 06-19-2003, 03:43 AM
roys63's Avatar
Member
 
Last photo:
Join Date: Dec 2001
Location: Nc
Age: 63
Posts: 907
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
You need to T into the line at the carb and adjust regulator running.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 06-20-2003, 10:54 AM
Jag Daddy's Avatar
British Style with USA Muscle
 
Last photo:
Join Date: Mar 2003
Location: Valencia, California
Age: 57
Posts: 1,078
Wiki Edits: 0

Thanks: 7
Thanked 0 Times in 0 Posts
Waterhead,

You might be measuring back pressure, you should tee it into the line with it hooked up to the carb. In normal operation the fuel line would hardly ever have zero flow for any extended period of time. Also what type of regulator is it? I had a vacuum controled regulator years ago on a 351M motor with a Carter Super Pump. But when I would first start the engine I always had a higher pressure until the vacuum came up.

Regards
Mark
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 06-20-2003, 08:39 PM
New Member
 
Join Date: Nov 2002
Location: Australia
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks for your posts...I will go buy a tee section and measure the pressure and see how I go.


Thanks again.
Reply With Quote Quick reply to this message

Recent Engine 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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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



All times are GMT -6. The time now is 06:14 PM.


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.