No gas in clear fuel filter but car runs great, why??? - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
LinkBack Thread Tools Display Modes
post #1 of 10 (permalink) Old Apr 19th, 05, 06:42 PM Thread Starter
Senior Tech
 
Join Date: Apr 2001
Location: Newark, Ohio
Posts: 712
No gas in clear fuel filter but car runs great, why???

After getting my new 383 dialed in and running really good, I just cant figure out the fuel system on this car. I have a Holley 110 mechanical fuel pump running into -6 hose to a NAPA Gold clear filter right up to the carb. Sometimes the filter is full at idle but most of the time the filter only has about 1/4" of fuel in it and the fuel pressure guage reads zero but the car runs great. Sometimes it is full and reads about 7-8 at idle but for the most part always reads zero pressure. I have the stock lines going into the stock tank with an SS cap on the back. Should I be worried about this or since its running fine its obviously getting fuel. I will be taking it to the track sometimes and dont want any problems. This car should run low 12's to high 11's.

Any suggestions? I can get pics of setop if needed.

Thanks, Erik

67 Camaro Pro Street, 540 Bill Mitchell Merlin big block, Merlin Aluminum heads, Holley 870, hydraulic camshaft, 2" Hooker Super Comp headers, Mallory and Crane ignition system, TH400, 2600 stahl, Ford 9" w/ 4:10 gears and posi.
Erik Beckett is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old Apr 20th, 05, 08:43 AM
Super Moderator
Jake-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 29,444
Re: No gas in clear fuel filter but car runs great, why???

Some thoughts pop into my head,
1. Gas cap a vented one? An unvented cap will create a vacuum in the tank and after awhile, no fuel.
2. Pump not primed?
3. Leak in fuel line from tank forward? A pinhole in the steel line, a dry rotted fuel hose at the tank sending unit, or right behind the pass rear wheel.
4. Sending unit sock at pickup is broken and restricting the line?
5. Fuel line close to an exhaust component and causing fuel to evaporate?

I take a long, 6-8 foot, clear vinyl hose and place it over the pump inlet tubing and dump it into a gas can. The long length so I can see the hose and delivery from the rear of the car. I remove the gas cap and insert an air nozzle covered by a rag into the fill tube. I pressurize the tank and watch the flow from the vinyl hose. It should be coming out very good. I give the tank about a 3-5 second shot of air, don't worry, you're not going to damage anything with short squirts of air.

If no leaks are found, you could do a vacuum check on the pump to see if it does draw a vacuum on its inlet side with a vacuum gauge. It should at least develop 10 in/Hg. of vacuum.

You might even hook your Mighty Vac gun to the fuel line and see how easy/hard it is to suck fuel from the tank.

Fuel filter should be full. It could be due to evaporization. You might try a different brand and hopefully get a 'summer' mixture. Winter mixtures don't do well in warmer climates.

Give a man a rescued dog for the health of both their souls.
'With age comes wisdom, but then wisdom ages you even more.'Other Stuff' CUBS - 2016 World Series Champions
Everett#2390 is offline  
post #3 of 10 (permalink) Old Apr 20th, 05, 01:57 PM
Senior Tech
67 Camaros Rock
 
Joe Harrison's Avatar
 
Join Date: Oct 1998
Location: Tucson Arizona
Posts: 7,111
Re: No gas in clear fuel filter but car runs great, why???

Mine does the same thing with and edelbrock carb and stock fuel system. I know I don't have any leaks and don't have restriction at the fuel pick-up in the tank. Never been able to figure it out. I don't have a fuel pressure gauge on it to see what's happing so no info there. I have had 4 different fuel filters and they all do the same thing. I have thought maybe a weak fuel pump? Sometimes it's full and sometimes you don't see much fuel in it at all?

Joe

"If you can leave black marks on a straight from the time you exit a corner till the time you brake for the next turn.......
Then, you have enough horsepower."
-Mark Donahue
My 67 Camaro Time Line http://www.camaros.net/forums/133-build-projects/211805-my-67-camaro-time-line.html
Joe Harrison is offline  
post #4 of 10 (permalink) Old Apr 20th, 05, 10:05 PM
Senior Tech
Brandon
 
Join Date: May 2004
Location: Monroe, NC
Posts: 1,977
Re: No gas in clear fuel filter but car runs great, why???

If your carb is getting too hot, the fuel will expand as vapor and push the fuel back too. I solved that problem on mine by putting a spacer between the carb and manifold.

Brandon J. licence 1NASTY67
My 67 Camaro
Nantooch is offline  
post #5 of 10 (permalink) Old Apr 21st, 05, 04:50 AM Thread Starter
Senior Tech
 
Join Date: Apr 2001
Location: Newark, Ohio
Posts: 712
Re: No gas in clear fuel filter but car runs great, why???

I know i dont have any fuel leaks anywhere and i cant imagine the gas is evaporating because it will do it even when the motor isnt warmed up yet. I have a feeling it has to do with pressurizing the system. I know my last car did the same thing as well. I have a feeling alot of cars are like this but they dont run a clear filter to actually see it happen. I will try to pressurize the tank and see what happens.

Any other thoughts?

Thanks, Erik

67 Camaro Pro Street, 540 Bill Mitchell Merlin big block, Merlin Aluminum heads, Holley 870, hydraulic camshaft, 2" Hooker Super Comp headers, Mallory and Crane ignition system, TH400, 2600 stahl, Ford 9" w/ 4:10 gears and posi.
Erik Beckett is offline  
post #6 of 10 (permalink) Old Apr 21st, 05, 09:02 AM
Super Moderator
Jake-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 29,444
Re: No gas in clear fuel filter but car runs great, why???

As seen in my sig, I have a MCSS. Now has a carb and mech fuel pump with a clear filter at the carb inlet. Its always full of gas.

You can "tee in" a vacuum gauge on the fuel pump inler side to see what the pump is sucking. You can even run the gauge up to the w/shield and duct tape it on to view while driving.

Is the filter full when first startup of the day, when everything is at ambient temperature?

Give a man a rescued dog for the health of both their souls.
'With age comes wisdom, but then wisdom ages you even more.'Other Stuff' CUBS - 2016 World Series Champions
Everett#2390 is offline  
post #7 of 10 (permalink) Old Apr 21st, 05, 10:24 AM
Gold Lifetime Member
Robert
 
Join Date: Oct 2000
Location: Simpsonville, SC
Posts: 3,349
Re: No gas in clear fuel filter but car runs great, why???

Both my cars have the same issue, clear filter, sometimes full, sometimes almost empty, always run great. I gave up on trying to figure it out. Didn't ever check the pressure though. One has a Carter high vol pump, the other I've removed the sock, replaced the pump, the rubber lines and cap. There seems to be no pattern to it. The '69 had been sitting for awhile and last night I hit the switch and it barely fired and the filter went from empty to full in a blink. Other times it's idling almost empty. I found some old post on this sometime back but never a clear resolve. I've decided it must have something to do with which way the wind is blowing.

Robert
'69 355ci 10:1, 64cc Edelbrocks, Comp Mag 280H, Performer RPM, 700r4 (2000 stall), 3.55 posi A/C PS PDB Hotchkis
'67 369ci 10.3:1, 64cc Edelbrocks, Voodoo 276/284, Performer RPM, Holley 650DP ...T56 Magnum, 3.73 Moser 12 bolt
TC member #18
rojo is offline  
post #8 of 10 (permalink) Old Apr 21st, 05, 02:00 PM
Senior Tech
67 Camaros Rock
 
Joe Harrison's Avatar
 
Join Date: Oct 1998
Location: Tucson Arizona
Posts: 7,111
Re: No gas in clear fuel filter but car runs great, why???

Mine is the same as posts above. It never seems to be the same, I do run an e-brock carb anyone else running one with the same problem?

Joe

"If you can leave black marks on a straight from the time you exit a corner till the time you brake for the next turn.......
Then, you have enough horsepower."
-Mark Donahue
My 67 Camaro Time Line http://www.camaros.net/forums/showthread.php?t=211805
Joe Harrison is offline  
post #9 of 10 (permalink) Old Apr 21st, 05, 04:18 PM Thread Starter
Senior Tech
 
Join Date: Apr 2001
Location: Newark, Ohio
Posts: 712
Re: No gas in clear fuel filter but car runs great, why???

Well, today I installed an Autometer fuel pressure gauge and it works now. But I still dont understand why the fuel filter would not fill up to even half way. I am getting a steady 7.5 on the gauge so that makes me feel better.

Thanks, Erik

67 Camaro Pro Street, 540 Bill Mitchell Merlin big block, Merlin Aluminum heads, Holley 870, hydraulic camshaft, 2" Hooker Super Comp headers, Mallory and Crane ignition system, TH400, 2600 stahl, Ford 9" w/ 4:10 gears and posi.
Erik Beckett is offline  
post #10 of 10 (permalink) Old Apr 21st, 05, 05:01 PM
Gold Lifetime Member
Robert
 
Join Date: Oct 2000
Location: Simpsonville, SC
Posts: 3,349
Re: No gas in clear fuel filter but car runs great, why???

Joe, both mine are Holleys

Robert
'69 355ci 10:1, 64cc Edelbrocks, Comp Mag 280H, Performer RPM, 700r4 (2000 stall), 3.55 posi A/C PS PDB Hotchkis
'67 369ci 10.3:1, 64cc Edelbrocks, Voodoo 276/284, Performer RPM, Holley 650DP ...T56 Magnum, 3.73 Moser 12 bolt
TC member #18
rojo is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech 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 email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



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.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Best Method for Painting Z28 Stripes & Cowl? hugger_sixty_nine Body Shop 25 Mar 5th, 04 04:27 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 On
Pingbacks are On
Refbacks are On

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