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> Need Diagnostic Help!, my carbs are starving for fuel....
nine14cats
post Mar 29 2004, 12:08 AM
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Bill Pickering -- 914-6 GT aka....Leeloo
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I have a problem with my carbs after they get heat soaked. It happened at a Time Trial at Buttonwillow earlier this month and again at a 2 day Zone Auto-x this weekend.

The morning runs when cool are fine...full power, great throttle response everything wonderful...then the afternoon comes, it warms up...the car has been run hard several times and bam.....the car feels like the fuel pump is giving out and is starving for fuel. The car sputters under hard acceleration and if I pump the throttle I will get the car to rev out. Normally redline is 7200....I can't get it past 6K after she heats up.

The car is a 2.7L 6 with 10.5 compression and triple throat webers on each bank...

Anyone have a suggestion on what it is?

oh yeah...I'm leaving for a 3 day event at Thunderhill this Thursday, so I 've got to find the problem ASAP.

Bill P.
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Brad Roberts
post Mar 29 2004, 12:12 AM
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Give me the current break down on the fuel supply system.

You ran the Airport ?


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nine14cats
post Mar 29 2004, 12:19 AM
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Bill Pickering -- 914-6 GT aka....Leeloo
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Hey B,

Yep, ran the airport...I think I finished 2nd overall both days...or somewhere close...but the car was driving me nuts with the friggin hiccups!

Fuel delivery system.....in order:

1. Stock tank
2. Fuel filter at tank
3. 911 fuel pump at tank
4. SS line through the tunnel
5. Flex hose to another fuel filter
6. Fuel pressure regulator
7. Into the carbs (I think)

The car is still in the trailer...just got back...will unload tomorrow and start fiddling.

Do you think the pump may be going bad?
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Brad Roberts
post Mar 29 2004, 01:07 AM
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Get rid of that POS pump and buy a Holley Blue or Red pump. Something with some real volume. It sounds like you are emptying the float bowls.


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ArtechnikA
post Mar 29 2004, 05:54 AM
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the "Float Bowl Vent Mod" also addresses this issue.
PMO sells the jig, but there has to be someone in your neck of the woods that had done it and has a jig sitting in a drawer...

the mods are described in Anderson/2 pp 149-150.

have you got the Bakelite insulator blocks ? are you running a Cool Can? (just wondering - i haven't had a heat-soak condition to this extent and was wondering if it'd help ...
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Gint
post Mar 29 2004, 08:49 AM
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And fuel starvation problems when hot could also be a result of a partially blocked fuel line or tank pickup. Sounds wierd I know, but BTDT.
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Rusty
post Mar 29 2004, 09:35 AM
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QUOTE
are you running a Cool Can?


A what? (IMG:style_emoticons/default/blink.gif)

-Rusty (IMG:style_emoticons/default/smoke.gif)
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ArtechnikA
post Mar 29 2004, 09:40 AM
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QUOTE(Lawrence @ Mar 29 2004, 07:35 AM)
QUOTE
are you running a Cool Can?

A what?

typically a drag racer / AX'er trick.

it's a container - typically limited in volume by regulation (IIRC SOLO-II is 1-qt) into which you put cold stuff. ice, dry ice & alcohol - something like that. plumbed into the fuel system, near the carburetor(s). flash-cools the fuel for increased density.
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nine14cats
post Mar 29 2004, 10:05 AM
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Bill Pickering -- 914-6 GT aka....Leeloo
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hmmm...holley pump huh?

Gint, I pulled the line last week and found some crap there, thought that might be it. Put it back together and bam...still the same problem.

I really think it's something with the pump or fuel delivery to the carbs...just haven't found it. No pressure, only a few days until 3 track days in mid 70's to mid 80's heat. I really want to fix this before getting there. I hate this shit at the track.

Thanks,

Bill P.
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KenH
post Mar 29 2004, 10:24 AM
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Hummm
You only need about 4# fuel pressure - I wonder if the 911 fuel pump is over powering the regulator when it is hot.

I would also inspect each main jet - it only takes 1 carb to cause that kind of problem.

See yea Friday.

Ken 180
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Rusty
post Mar 29 2004, 10:56 AM
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QUOTE
t's a container - typically limited in volume by regulation (IIRC SOLO-II is 1-qt) into which you put cold stuff. ice, dry ice & alcohol - something like that. plumbed into the fuel system, near the carburetor(s). flash-cools the fuel for increased density.


Ice and alcohol? (IMG:style_emoticons/default/w00t.gif)

I put that in a container called a GLASS! (IMG:style_emoticons/default/beer3.gif)

-Rusty (IMG:style_emoticons/default/smoke.gif)
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d914
post Mar 29 2004, 03:48 PM
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have heard some bad things about the new holleys, was told to look at the mallory or the aeromotive
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Gint
post Mar 29 2004, 05:17 PM
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QUOTE
Gint, I pulled the line last week and found some crap there, thought that might be it. Put it back together and bam...still the same problem.


Have you checked the bottom of the tank?
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