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Split 1 Samba Member
Joined: May 03, 2005 Posts: 764 Location: Adelaide. South australia
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Posted: Fri Aug 21, 2009 1:53 am Post subject: Fuel Pressure Drop? |
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I am running an electric pump, have a holley guage and when I start the engine which has twin 40mm Dells with 38 venturies/chokes, the Holley guage reads 4 lbs pressure, after about 5 mins it reads nothing, the carbies still work, ( we are waiting on some jets but it runs) why would the presure drop, I switch the motor off, it still stays at less than 1 lb pressure.
Have changed the pump, have cleaned everything???
Come back to the engine in a hour os the next morning, first switch the ignition on the guage reads 4lbs, start engine same again??
Any ideas???
Dave |
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sturgeongeneral Samba Member
Joined: June 23, 2005 Posts: 2460 Location: Sacramento, California
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Posted: Fri Aug 21, 2009 12:39 pm Post subject: |
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Have you cleaned the screen in the bottom of the gas tank? Sounds like you have restricted flow. _________________ Street legal fiberglass rocket ship
2005 Lotus Elise supercharged
1974 Chevy Corvette
My fiberglass car collection!
In honor of bowtie56jw:Another victim of the nasty "C" Praying for ya Jeff!
My exwife said if I towed home one more bug she would leave me. You know, every once in a while I miss her |
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Split 1 Samba Member
Joined: May 03, 2005 Posts: 764 Location: Adelaide. South australia
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Posted: Fri Aug 21, 2009 3:11 pm Post subject: |
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Yes, even replaced the guaze sock in the tank and fitted a new in-line filter??
Dave |
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Guack007 Samba Member
Joined: June 23, 2009 Posts: 87 Location: Portland OR
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Posted: Fri Aug 21, 2009 3:45 pm Post subject: |
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You checked the floats? |
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Split 1 Samba Member
Joined: May 03, 2005 Posts: 764 Location: Adelaide. South australia
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Posted: Sat Aug 22, 2009 3:40 pm Post subject: |
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No havent checked the floats, ,,,how would that alter the pressure??
Thanks
Dave |
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A.J.Sims Banned
Joined: December 11, 2003 Posts: 1016 Location: LowBugget.com 982 N Batavia A4 Orange Ca 92867
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Posted: Sat Aug 22, 2009 5:16 pm Post subject: |
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vapor lock?
Take the cap off and retest! _________________ Have tech questions? Need real help? Give us a call.
www.Lowbugget.com
982 North Batavia A4, Orange Ca 92867.
68 drag bug 1915cc 10.50's @130mph
66 fastback 2387cc turbo street car
67 baja 2054cc turbo. |
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Split 1 Samba Member
Joined: May 03, 2005 Posts: 764 Location: Adelaide. South australia
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Posted: Sat Aug 22, 2009 6:38 pm Post subject: |
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Tried removing the cap, no change ????
Dave |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sat Aug 22, 2009 7:14 pm Post subject: |
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it could be just a bad sender. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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Split 1 Samba Member
Joined: May 03, 2005 Posts: 764 Location: Adelaide. South australia
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Posted: Sun Aug 23, 2009 4:45 am Post subject: |
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Tried new carbies, no change.
Tried squeezeing the pipe needle goes up??
Dave |
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Split 1 Samba Member
Joined: May 03, 2005 Posts: 764 Location: Adelaide. South australia
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Posted: Sat Aug 29, 2009 1:21 am Post subject: |
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If you come out to a cold engine, switch ignition on and pump, I get 4psi, then drive for 10 mins get 1psi but it still drives.
Guage working fine when you squeeze the fuel pipe ,the needle moves???
Dave |
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JustBarry1972 Samba Member
Joined: May 19, 2008 Posts: 263 Location: England
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Posted: Sat Aug 29, 2009 10:09 am Post subject: running out of fuel |
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Hi, i found this thread looking for a fix for my fuel prob... i drive about half a mile and run out of fuel - ie coughs and splutters, i jump out and with engine off give the throttles a blip (dual dells) and no fuel squirts from any barrell.
I wait a while for the fuel filters to fill before and after the pump to fill up (5 mins? ) then blip the throttles and see fuel from all.
ive rebuilt the carbs twice without finding any dirt. Ive replaced the fuel pump as it trickles into the empty filter pre mechanical pump.
ive left my car with the front jacked so the tank is above my carbs (cars raked when diving)
will the filters ever stay full once filled? or do they allways turn to vapour? |
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teamasr Samba Member
Joined: August 04, 2009 Posts: 159 Location: SF Bay Area
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Posted: Tue Jan 26, 2016 9:22 pm Post subject: Re: Fuel Pressure Drop? |
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Split 1, did you find a solution to the problem? My motor seems to be doing the same exact thing. Running duel webers, holley regulator, liquid filled gauge and electric pump. After a minute of idling, pressure drops to zero or near zero with engine running, but exhaust starting to make popping sound. |
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Split 1 Samba Member
Joined: May 03, 2005 Posts: 764 Location: Adelaide. South australia
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Posted: Wed Jan 27, 2016 3:12 am Post subject: Re: Fuel Pressure Drop? |
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Sorry never did fix it and it carried on driving?
Since sold it so not sure what it was |
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modok Samba Member
Joined: October 30, 2009 Posts: 26790 Location: Colorado Springs
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Posted: Wed Jan 27, 2016 3:19 am Post subject: Re: Fuel Pressure Drop? |
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The first thing I think if I hear "pressure falling" and "liquid filled gauge" in the same sentence
is
The gauge is leaking internally. |
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