Carburetors at high altitude
mriplaybass
Full Time Jeeper
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- 2,345
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- Location
- Wisconsin
- Vehicle(s)
- 1979 CJ7 304 T18 w/6.32 lo d20 w/3.15 TeraLo D44 rear & D30 Front w/4.56 Eaton Elockers front and rear,
1959 CJ5,
1954 CJ3B,
1967 CJ5,
1947 IHC KB1,
1947 IHC KB2,
1947 IHC KS5,
1967 Mustang Coupe,
Getting back to the fuel issues. A little more information from personal experience. Although there has been a lot of discussion on the carburetor, fuel filter orientation, OEM pump, etc., the problem that several of us have had is not occurring under the hood. As I stated before. The fuel is vaporizing in the fuel line before the pump, whether it is electric or mechanical.
I specifically wanted to test my theory, so we installed a digital fuel pressure gauge on the dash board. The sending unit is between the pressure regulator and the carburetor. That way, I know that if there is fuel pressure showing, barring a stuck float, gas will be getting to the carburetor. Every time we had problems, the fuel pressure suddenly dropped to 0. Once the gas in the float bowl was depleted, the engine quit. I could hear the fuel pump cavitating. After the Jeep sat for a while and cooled off, I would turn the key on, and could hear the pump catch prime. Once I could hear the pump slow down, I knew gas was flowing because the pressure gauge would go back to where the regulator was set. Once this occurred, the engine started immediately. I have seen and heard this happen to others who used a similar set up.
I specifically wanted to test my theory, so we installed a digital fuel pressure gauge on the dash board. The sending unit is between the pressure regulator and the carburetor. That way, I know that if there is fuel pressure showing, barring a stuck float, gas will be getting to the carburetor. Every time we had problems, the fuel pressure suddenly dropped to 0. Once the gas in the float bowl was depleted, the engine quit. I could hear the fuel pump cavitating. After the Jeep sat for a while and cooled off, I would turn the key on, and could hear the pump catch prime. Once I could hear the pump slow down, I knew gas was flowing because the pressure gauge would go back to where the regulator was set. Once this occurred, the engine started immediately. I have seen and heard this happen to others who used a similar set up.