Fuel Lines are wrong but how wrong? - JeepForum.com
 
LinkBack Thread Tools
post #1 of 7 Old 04-18-2009, 08:58 PM Thread Starter
flybo
Registered User
1982 CJ7 
 
Join Date: Mar 2009
Location: TN
Posts: 18
Fuel Lines are wrong but how wrong?

I posted a thread about the PO had not put a fuel filter on and the there was no return line back to my tank. Well I finally dug underneath and found what goes where, here is how my fuel lines run and can anyone tell me how bad this is. My Jeep seems to run fine, what little I have driven it. From my sending unit a line to the fuel pump then over to the carb but it has not filter, but a gap there for it. The other line from my send. unit runs down the drivers side. up to the motor area but it is just cut off. From the outlets on the tank, one runs to the Liquid check valve to the roll over valve, up the drivers side to the motor area and it is not connected to anything either. Do I really need to connect the one line that is cut off it a charcoal canister? And could I just install a filter and buy a rubber hose connecting it to the other line that is cut off which goes back to the tank? Thanks this JF has helped alot!

flybo is offline  
Sponsored Links
Advertisement
 
post #2 of 7 Old 04-19-2009, 01:14 AM
only in a jeep cj
Registered User
1986 CJ7 
 
Join Date: Jun 2001
Location: Mobile
Posts: 5,446
Larger one from sending unit goes to metal line on passenger side up to pass side motor mount, then rubber line to fuel pump, then hard line to filter in front of carb. Filter has one inlet and two outlets. The smaller outlet (the offcenter one) runs down to a hardline on the drivers side of engine and back to tank via hardline down drivers side. Venting is from rubber line from tank valves, to hard line drivers side up to carcoal canister. Carb is also vented into this canister. Engine vacumn is also used.
If the PO removed the return type of filter, they MAY have used a pre 76 fuel pump that was used when there wasn't return lines. My 75 CJ-6 was like that. I would get the correct pump and filter on there and vent as needed.

Ed
1975 CJ-6 1983 CJ-8
1986 CJ-7 Laredo 1986 TJ-7 Trail Jeep
2003 Inca Gold TJ Rubicon
only in a jeep cj is online now  
post #3 of 7 Old 04-19-2009, 04:35 AM
keith460
Jeep. There's Only One
 
keith460's Avatar
1984 CJ7 
 
Join Date: Jan 2007
Location: Doylestown, PA
Posts: 7,043
This is what you should as mentioned above:





keith460 is offline  
 
post #4 of 7 Old 04-21-2009, 06:18 AM
mundy1
Registered User
1976 CJ7 
 
Join Date: May 2008
Location: Michigan
Posts: 23
Keith,
You photos are great.
I am in the same spot as the OP. I only have the feed line and the vents currently with no return or canister. Even with your photos I am still confused about the location of the filter with the return.

I see the location of your filter between the pump and carb, but won't the pressure be relieved by the return line leaving the carb with very little presure? I thought the carb needs around 5PSi to fill proper.

Am I not looking at it right or just thinking too hard?

Any insight would be a great help.

Mundy
mundy1 is offline  
post #5 of 7 Old 04-21-2009, 06:30 AM
Mike Romain
Registered User
1986 CJ7 
 
Join Date: Nov 2007
Location: Off the Grid in Chester Grant
Posts: 18,083
Quote:
Originally Posted by mundy1 View Post
I see the location of your filter between the pump and carb, but won't the pressure be relieved by the return line leaving the carb with very little presure? I thought the carb needs around 5PSi to fill proper.
The stock filter has a metered hole in the return line nipple. This is set to hold the right back pressure for proper carb running so there are no issues with pumping all the gas back to the tank.

That is also one reason it is important to have that return line at the top of the filter. The other reason is gas will just siphon back to the tank vapor locking it when it sits if the return isn't up top.

Folks that need a lower fuel pressure like for some aftermarket carbs 'could' just open this metered hole up more which would lower the pressure. It can likely even be mathematically figured, stock hole size allows X back pressure, etc...

Mike
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00, 'New' frame,wires and plumbing in '09. Carter BBD Carbed 4.0 HO in '10.
89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
Some Canadian Bush Jeep Runs and Build Photos:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
(10 new albums added Sept 16/10)
Mike Romain is offline  
post #6 of 7 Old 04-21-2009, 07:42 AM
keith460
Jeep. There's Only One
 
keith460's Avatar
1984 CJ7 
 
Join Date: Jan 2007
Location: Doylestown, PA
Posts: 7,043
Quote:
Originally Posted by Mike Romain View Post
Folks that need a lower fuel pressure like for some aftermarket carbs 'could' just open this metered hole up more which would lower the pressure. It can likely even be mathematically figured, stock hole size allows X back pressure, etc...
I would be interested in this mathematical formula as I have a Weber carb installed and do not want to use a fuel pressure regulator to reduce pressure to the desired 3 psi. I guess I'll wait until start up of the engine, carb adjustments and or if any new jets are needed to get the Weber carb to run correctly.

Another reason to have the fuel return line is the fact that fuel may be heated during idle and the return line insures a fresh fuel supply as it circulates through the system. This helps to prevent vapor lock also.
keith460 is offline  
post #7 of 7 Old 04-21-2009, 07:51 AM
mundy1
Registered User
1976 CJ7 
 
Join Date: May 2008
Location: Michigan
Posts: 23
Thank you so much.
It all makes sense now.

Mundy
mundy1 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user 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 e-mail address for yourself.



Email Address:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
What would happen ifyouhad your fuel filter on wrong... Blthomas Jeep CJ Forum 3 07-17-2009 07:00 AM
Fuel Filter-Did I get wrong one? what is this for... Floridazed Jeep CJ Forum 8 12-14-2008 01:15 PM
Temp/Fuel gauge? What did I do wrong? ultramax Jeep CJ Forum 8 07-18-2007 01:00 PM
Fuel Gauge read wrong mike.clubb@hotm Jeep CJ Forum 4 03-20-2006 11:34 AM
RE lift brake lines wrong size? Jermy01 Jeep CJ Forum 4 05-28-2005 01:33 AM

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 Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome