g9m3c Posted November 17, 2008 Share Posted November 17, 2008 From my understanding, my 10/74 260Z has both a mechanical fuel pump and an electric fuel pump in front of the tank. What is the purpose in having two of them? Can the electric one by replaced by a universal in-line pump, or deleted all together? I've never heard of a car with two fuel pumps. Someone smarter than I, please enlighten me. Quote Link to comment Share on other sites More sharing options...
g9m3c Posted November 17, 2008 Author Share Posted November 17, 2008 Anybody? Quote Link to comment Share on other sites More sharing options...
clayton 260Z Posted November 17, 2008 Share Posted November 17, 2008 g9m3c, The electric fuel pump was added to help with fuel delevery when the car was hot and to try and help with vapor lock issues, it only starts working when the starter is engaged I believe. It is located in front of the tank and is a pusher. Under normal use the mechanical pump should work fine without the electric. I use a carter electric pump all on its own with a fuel regulator set at 3 psi with SU carbs. Mike Quote Link to comment Share on other sites More sharing options...
Lukaniuk Posted November 17, 2008 Share Posted November 17, 2008 I have used just the mechanical pump with triple webers before with no issues. Quote Link to comment Share on other sites More sharing options...
g9m3c Posted November 17, 2008 Author Share Posted November 17, 2008 Alright, thanks guys. If I can't get the electric pump to work, then I'll just bypass it and see how it goes. Quote Link to comment Share on other sites More sharing options...
Daeron Posted November 20, 2008 Share Posted November 20, 2008 Yah, the mechanical is the primary pump; the electric is there to supplement it. You may have noticed (or I may be wrong about your flattop setup and this only applies to the earlier, mechanical pump only cars) but there is no fuel pressure regulator either.. the mechanical pump delivers the fuel needed for the engine at any given RPM. More than enough to keep the float bowls full anyhow. Its probably hard to see it, looking at your Falttops, but when it was first put together the dual SU carburetor setup used by nissan was an AMAZINGLY WONDERFULLY well designed fuel intake; Essentially the same setup is used on everything from the mid sixties through 1980s and fuel injection. A few vehicles came with downdraft setups (mostly larger 4 cylinders or the ultra econobox 210s) but any of the cars COULD be run with SUs if you could get a manifold for the engine, and frequently were. Simple, Effective, Potent, and Reliable. Then the US Gov'mint told 'em they had to comply to fifty bajillion pollution control laws because the American Public couldn't dontrol their own excessive behavior, and they (the cheap Japanese economy car company) decided it would be cheaper and easier to go with computer controlled fuel injection. Not many other inexpensive car companies switched over their entire US production line to EFI like Nissan did.. Starting in '75 with the Z, every car in due time was FI, and the last to succumb was the venerable Datsun Pickup; Not until it was a Nissan Hardbody (late 86) but when it did, All nissans (AFAIK) were fuel injected. /history lesson Quote Link to comment Share on other sites More sharing options...
a1953mdl Posted June 20, 2009 Share Posted June 20, 2009 Daeron write: ) but there is no fuel pressure regulator either.. I know this is a little old post but ..... What controls the flow back thru the return line? Seems like there would need to be some type of pressure regulator to maintain the 3 psi to the carbs. I am thinking of changing to an electric only fuel pump as both mech and electric is bad on my project. Or could I just run the aftermarket electric pump and not worry about the pressure. i think it has 6-7 psi. Would the return line handle the extra pressure? Lee Quote Link to comment Share on other sites More sharing options...
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