1969 GTX....The T stands for tetanus

[threewood]

Slight update. Back from vacation. Pulled the carb off and ran temp sheathing down the fuel line to the pump. I took the carb top off and one of the floats was not set up correctly so I adjusted it per the manual. While I was in it I upped the secondary jets and used the next step up rod for the primary just to see how it reacts up top.

I have the fuel gauge and fittings so it should be ready to drive and test tomorrow.

 

[threewood]

I have it all hooked up and ready to go. I fired it up and at idle the fuel is a rock steady 7psi which is pushing the limits of the carb. I believe 6.5psi max is called for in the manual and it does smell a bit rich at the tailpipe. Maybe pushing past the float?

I also rotated the needle covers over and observed the step down operation. Both are pulled down tight at idle and they pop up when revved. Should be good. Road test is next although it is a cool 103 today so we shall see.

You can see the psi gauge tee and the fuel line sleeve.

 

[69 GTX]

I have "heard" the rubber hose is more prone to vapor lock than steel, but I can't confirm this. Good luck.

 

[oldbee]

Wellll "back in the day" I ran a Holley elec. pump with 5/16" neoprene to a 440 with a Holley 850, shifting at 6000 and never had a problem, aluminum foil around line to behind alternator w/o a vapor cannister and never had a problem, course that was "good" gas back then. I know what everyone says about rubber fuel lines but you have to remember a hose is measured by I.D. and a steel line is measured O.D. Just saying. Oh, 5/16" pickup in the tank.

 

[oldbee]

Also had a regulator hooked up to limit press. to 6-6.5#.

 

[threewood]

I have "heard" the rubber hose is more prone to vapor lock than steel, but I can't confirm this. Good luck.

Rubber is minimal. Only connecting the steel line going to pump and on both sides of the filter.

Road test results. At cruise and idle, pressure is between 5 and 4.5psi. At moderate throttle it dips down to 3. If I go wot, it will eventually drop to zero. I assume this isn't normal? When I feather it the psi catches up.

Drove it home tonight, 89 degrees outside. At cruise it was steady at 6psi. At WOT it didn't drop below 3psi. Ran great and it revved a little quicker at the top end. Hot, crappy fuel....yay! 91 octane is highest available out here, all corn gas too.

 

[threewood]

I have "heard" the rubber hose is more prone to vapor lock than steel, but I can't confirm this. Good luck.

I heard it as well. It cannot shed heat as fast as steel. It should "hopefully" be a moot point as I just ordered a holley black pump and regulator. Mount the pump by the tank, install relay to run pump, run steel line up to inner fender, mount regulator to inner fender and connect hardline, remove edelbrock pump and hopefully get my money back for it since it cannot keep up.

 

[69 GTX]

Which Eddy pump was it? Also do you have a phenolic spacer under the carb?

 

[threewood]

Which Eddy pump was it? Also do you have a phenolic spacer under the carb?

Yes to the spacer.
Pump is a Performer RPM Street Fuel 1723. 110gph free flow, 6psi, 3/8 npt fittings

 

[69 GTX]

I bought a Eddy for mine, I'll check it to see which one it is. I think it's on my thread, so I'll look. Thanks!

 

[threewood]

I bought a Eddy for mine, I'll check it to see which one it is. I think it's on my thread, so I'll look. Thanks!

Like I posted earlier it is only an issue in the afternoon heat, 100*+. I don't know how hot it gets in Iowa but I doubt it comes close to AZ summers. Plus, if you have access to non ethonol blend fuel the better.

I have re ran the hard lines away from any heat, used heat sheathing, phenoletic spacer, so my last option is to try an electric pump. I can venture to guess the pump body is transferring enough heat to boil it before the carb. I don't have access to good gas, maybe race fuel if I can find it.

 

[69 GTX]

I thought about plumbing my AC condenser water drain to drip on the fuel line to help cool it off. I'd be interested to know how loud your fuel pump will be.

 

[dryheat]

http://www.sellerspetroleum.com/racing-fuels

 

[threewood]

http://www.sellerspetroleum.com/racing-fuels

Hahaha!!!!! Great minds think alike. I got off the phone with them an hour ago. They sell 110 by the gallon, into containers of course. I'm going to guess it is not cheap either.

 

[threewood]

I thought about plumbing my AC condenser water drain to drip on the fuel line to help cool it off. I'd be interested to know how loud your fuel pump will be.

I have heard it may be loud, but I will let you know.

I'll figure out a mounting location when it gets here. I am thinking of modifying a muffler hanger to mount it and get as much isolation as possible. I cannot wait until I can get in, drive and enjoy my car.

 

[threewood]

On a lark, I ran a 1/4" hardline from a vented fuel filter to the return line on the sending unit. No real change other than a slight decrease in idle psi. I can take it medium to medium high throttle and it will stay at 3psi but as soon as I get into the secondaries the psi goes to zero.

Anyone recommend whether to run the electric fuel pump by itself or in conjunction with the mechanical?

 

[oldbee]

Bypass the mechanical.

 

[showard]

You've been busy. Your car sure looks and sounds great!

 

[Glenwood]

I was having a similar problem at idle. On a hot day, the car would stall if idling too long in traffic. Seemed to run out of gas. Adding a sock on the fuel line and spacer seemed to help, but it hasn't been that hot since, so I'm keeping my fingers crossed! My starter croaked yesterday leaving me high & dry and a $200 tow home. What a PITA.

 

[threewood]

I was having a similar problem at idle. On a hot day, the car would stall if idling too long in traffic. Seemed to run out of gas. Adding a sock on the fuel line and spacer seemed to help, but it hasn't been that hot since, so I'm keeping my fingers crossed! My starter croaked yesterday leaving me high & dry and a $200 tow home. What a PITA.

That stinks. I have found out there is percolation and vapor lock. Mine seems to be percolation as there is never a hot start issue, while vapor lock is fuel boiling out in the carb. My pump just cannot keep up at wot. I'm really hoping the electric pump does the trick and keeps up.