Hey guys. Buckner and Rocketraider commented some on this subject in a previous post. My car is a 63 Olds with the Starfire Ultra High Compression engine. I'm having similar issues that Buckner had. The previous owner rebuilt the mechanical fuel pump and also added an electric pump further back. According to my mechanic the electric pump was so strong it was holding the diaphragm closed in the mechanical pump. Currently I'm running with the mechanical pump bypassed but it's not sufficient for highway driving. Does anyone know of a good, known fix for these fuel issues? Do I need a less powerful electric pump in tandem with the mechanical pump - a more powerful electric pump to run on it's own - and also I need to learn about fuel pumps and their ratings.
Any advice is appreciated fellas.

 

on my 76 Custom Cruiser I was having stalling issues and an aux pump was added to the rear - I was against it but the car no longer stalls - I turn on the key, wait 5 seconds, pump the gas and it fires right up, idles high, and does not die like it used to

 

Thanks Jeffreyalman
Beautiful cars by the way!

 

thanks! the receipt says CARTER 12V PRIMER PUMP

 

ahhh...more good info....thanks!

 

I added the Mr.Gasket 12v fuel pump in tandem on a switch and it works great. No issues so far.

 

Hey Buckner, did the package indicate what psi ranges that pump operates in? I think my electric pump might be too string holding the diaphragm closed on the mechanical pump....

 

It says 4-7 psi. Its the Mr. Gasket 12s. I got mine at autozone but they are cheaper elsewhere on the nets.

 

awesome info buddy....
I think mine is too strong. Right now the mechanical pump is disconnected and I'm running only with the electric pump that a previous owner installed. I'll reconnect the mechanical pump and try a lower pressure electric pump.

 

The electric pump would be holding the valves in the pump in the open position
if every thing is assembled correctly. The pump pressure forces open the the inlet and outlet valves and the diaphragm chamber acts like a straight pipe. All the electric pump installations I've seen are in line with the mechanical pump and work that way.

Many are hidden in the rear and have a hidden switch so that the fuel delivery lines and pump look original for judging purposes.

If the electric pump is working properly you must have another undiscovered issue with the fuel system. Your pump should be delivering a steady standing pressure at the needle and seat in the carb.Check it at that location. The brass fitting that enters the carb at the end of the fuel line has a fine screen . If you are getting fuel with the fitting out of the carb., you have a problem with the carburetor not accepting the fuel provided by the pump.

But no matter what you do, even if you are using fuel with no ethanol, it is still RFG or Reformulated Gas and it will cause some vapor lock in high heat (parades) slow traffic and high speed or power situations. Don't forget you have an engine with 10+:1 compression and that creates a lot of internal heat. I have the same problem you have and I just turn the electric pump on before starting cold and when the driving situation requires it. Ditto that on my 1961 Dynamic 88 with 8.75 compression it still wants to vapor lock in those conditions with the crap we are sold as gasoline.
The convertable with the people standing around is at the top of Pikes Peak,made it O.K. (14139 feet) . Had a rough time the last half mile and found number 8 spark wire disconnected when I got home. ????????WTH.

Good luck with your problem,

Dave