Ways to restrict fuel pressure? - JeepForum.com

Reply
 
LinkBack Thread Tools
post #1 of 17 Old 05-18-2012, 09:05 AM Thread Starter
bluedaffy
Registered User
1989 YJ Wrangler 
 
Join Date: Oct 2011
Location: Stevens Point
Posts: 291
Ways to restrict fuel pressure?

I have a weber 32/36 that is showing all the signs of running rich from gas bypassing the needle and seat. I have checked the needle (rubber type) and seat many times and the function appears to be clean and promising, but yet the bowl overfills.

I have the return line hooked up on my fuel filter (12 o'clock position) and the return line is clear, but I'm still getting too much pressure at the carb.

Can I drill out the return line to allow more flow back to the tank?
Is there a way to use two fuel filters to reduce the pressure?
Is there a replacement fuel filter that has a larger return opening?


I know that I could probably get a fpr, but I don't want to add another thing that can go bad, when I could plumb something manually.

Evan

bluedaffy is offline  
Sponsored Links
Advertisement
 
post #2 of 17 Old 05-18-2012, 09:16 AM
skyj
Web Wheeler
1990 YJ Wrangler 
 
Join Date: Jan 2011
Location: Helena
Posts: 4,163
Quote:
Originally Posted by bluedaffy
I have a weber 32/36 that is showing all the signs of running rich from gas bypassing the needle and seat. I have checked the needle (rubber type) and seat many times and the function appears to be clean and promising, but yet the bowl overfills.

I have the return line hooked up on my fuel filter (12 o'clock position) and the return line is clear, but I'm still getting too much pressure at the carb.

Can I drill out the return line to allow more flow back to the tank?
Is there a way to use two fuel filters to reduce the pressure?
Is there a replacement fuel filter that has a larger return opening?

I know that I could probably get a fpr, but I don't want to add another thing that can go bad, when I could plumb something manually.

Evan
I just use a fuel pressure regulator. I've had it for 3 years and no problems. It works great, and its just a cheapo Mr gasket one.

build thread: http://www.jeepforum.com/forum/f22/skyj-eccentric-build-1467426/ '90 YJ 5.2 magnum MPI, AX15, NP231 SYE, Dana 30 4.56 open/ 8.8 4.56 detriot locker. 1" shackles
2" BL, 4" stretch all on saggy waggy springs.
skyj is offline  
post #3 of 17 Old 05-18-2012, 09:24 AM
superj
Registered User
 
Join Date: Mar 2008
Location: corpus christi
Posts: 7,057
Have you put a gauge to actually see what pressure is at the carb?

I don't feel like working on anything at this time so i sold my yj.
superj is offline  
post #4 of 17 Old 05-18-2012, 09:52 AM Thread Starter
bluedaffy
Registered User
1989 YJ Wrangler 
 
Join Date: Oct 2011
Location: Stevens Point
Posts: 291
No I haven't superj. I have a vacuum tester that says was advertised to be a vacuum and fuel gauge. I suppose this would work, I'm just not sure how to safely do that.
bluedaffy is offline  
post #5 of 17 Old 05-18-2012, 09:58 AM Thread Starter
bluedaffy
Registered User
1989 YJ Wrangler 
 
Join Date: Oct 2011
Location: Stevens Point
Posts: 291
The only reason I'm blaming fuel pressure at this point is because I don't know of anything else that can overfill the bowl other than needle/seat operation, but I am a newbie with carbs and I'm all ears if you have any ideas.
bluedaffy is offline  
post #6 of 17 Old 05-18-2012, 10:23 AM
Jeepsr4me
Registered User
 
Join Date: Dec 2004
Posts: 8,831
Quote:
Originally Posted by superj View Post
Have you put a gauge to actually see what pressure is at the carb?
This 1st... Stop not knowing. Know what pressure you got.
Jeepsr4me is offline  
post #7 of 17 Old 05-18-2012, 10:24 AM
Jeepsr4me
Registered User
 
Join Date: Dec 2004
Posts: 8,831
Quote:
Originally Posted by bluedaffy View Post
The only reason I'm blaming fuel pressure at this point is because I don't know of anything else that can overfill the bowl other than needle/seat operation, but I am a newbie with carbs and I'm all ears if you have any ideas.
A bad float can do it............
Jeepsr4me is offline  
post #8 of 17 Old 05-18-2012, 10:38 AM
Jax89Jeeper
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2011
Location: Jacksonville
Posts: 344
If tou are still on the mech pump, you should be running at 4 or 5 psi at the carb inlet... This is too much for the Weber which doesn't like more than 3 psi. If your float is all good, try a fuel pres. reg and that should fix the issue.
Jax89Jeeper is offline  
post #9 of 17 Old 05-18-2012, 10:47 AM Thread Starter
bluedaffy
Registered User
1989 YJ Wrangler 
 
Join Date: Oct 2011
Location: Stevens Point
Posts: 291
If by "bad float you are referring to a cracked one, or one that is somehow allowing fuel into the float, then no, the float is fine.

Jax89Jeeper, I have read that the weber likes anything up to 3.5 psi. Could 4 or 5 really be enough to overpower the needle/seat? And no, that wasn't sarcastic, I'm actually quite curious.

For a quick test to see if too much pressure is the problem could I just use a pair of pliers and pinch the fuel line going into the inlet of the carb and see if my idle smoothes out? Would that give me an accurate idea?

Thanks all!
bluedaffy is offline  
post #10 of 17 Old 05-18-2012, 10:55 AM
Jax89Jeeper
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2011
Location: Jacksonville
Posts: 344
Quote:
Originally Posted by bluedaffy
If by "bad float you are referring to a cracked one, or one that is somehow allowing fuel into the float, then no, the float is fine.

Jax89Jeeper, I have read that the weber likes anything up to 3.5 psi. Could 4 or 5 really be enough to overpower the needle/seat? And no, that wasn't sarcastic, I'm actually quite curious.

For a quick test to see if too much pressure is the problem could I just use a pair of pliers and pinch the fuel line going into the inlet of the carb and see if my idle smoothes out? Would that give me an accurate idea?

Thanks all!
A bad float could be cracked or sticking or out of adjustment... And yes 4 or 5 could really over power the carb inlet to the bowl. You are 30-50% over the spec the carb was designed to handle. This is a common issue when installing a Weber. If you already have the fuel pres./vac gage it is perfectly safe to follow the instructions and hook the gage up to the fuel line. Again, a good mech pump will read 4-5 psi.
Jax89Jeeper is offline  
post #11 of 17 Old 05-18-2012, 10:59 AM
Jeepsr4me
Registered User
 
Join Date: Dec 2004
Posts: 8,831
Floats need adjustment, they also can be bad as in cracked. All that will cause a raise in the needle and allow too much fuel in.
Jeepsr4me is offline  
post #12 of 17 Old 05-18-2012, 11:06 AM Thread Starter
bluedaffy
Registered User
1989 YJ Wrangler 
 
Join Date: Oct 2011
Location: Stevens Point
Posts: 291
Good to know! I don't know why, but I thought a little bit over 3.5 wouldn't affect things.

Now to test the fuel pressure with my gauge... How exactly would I go about doing that safely?
bluedaffy is offline  
post #13 of 17 Old 05-18-2012, 11:07 AM Thread Starter
bluedaffy
Registered User
1989 YJ Wrangler 
 
Join Date: Oct 2011
Location: Stevens Point
Posts: 291
I thought when the needle "raises" that is when it seats and does NOT let fuel in. Am I wrong on that?
bluedaffy is offline  
post #14 of 17 Old 05-18-2012, 11:31 AM Thread Starter
bluedaffy
Registered User
1989 YJ Wrangler 
 
Join Date: Oct 2011
Location: Stevens Point
Posts: 291
Okay, so I figured out how to measure the fuel pressure by doing some internet searches. You guys were right about making sure that was all in line, because it was bouncing between 1-2 psi which I think is normal because it's a mechanical pump. I measured after the fuel filter, basically taking the fuel line off the carb inlet and hooking the gauge up to that line.

Well then what could it be? The float isn't letting fuel in, and the needle and seat are absolutely clean...
bluedaffy is offline  
post #15 of 17 Old 05-18-2012, 11:50 AM
Jax89Jeeper
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2011
Location: Jacksonville
Posts: 344
What brand is the vac gage? Are you sure it is accurate? The results don't match the problem you are having with the carb, but could point back to the needle not seating on the carb showing a float or seal issue.
Jax89Jeeper is offline  
Reply

Tags
fuel filler , fuel pressure , fuel pressure regulator , weber

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
Gas Tank PRESSURE??? Or Fuel RELIEF PRESSURE?? 915kingwrangler YJ Wrangler Technical Forum 22 03-21-2016 05:33 PM
How do you release the fuel pressure at the fuel rail on a 2005 4.0? msully TJ Wrangler Technical Forum 7 11-14-2010 12:11 PM
Ways to make my jeep more fuel efficient 94YJTech YJ Wrangler Technical Forum 30 11-23-2009 05:17 PM
Fuel pressure too high - Fuel return line problems ChiroSean YJ Wrangler Technical Forum 4 08-11-2009 09:57 AM
Fuel Pump !!! No Pressure at Fuel Rail!!! turfman* YJ Wrangler Technical Forum 2 11-18-2002 10:26 PM

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