Has anyone had overfuelling issues at low rpm using an SU fuel pump? I read the Holley manual which says fuel delivery pressure should be 5-7 psi, and the SU delivers (in theory) 7psi..
I switch it on and tictictic-tik---tik-----tik and the pump comes to a complete halt, but it feels surgey if I use very light throttle at low rpm, kinda as if it's fuelling too much with every pump of the SU.
Beyond fitting a recirculating pressure relief (I have an inline one I'm tempted to fit) and wearing the pumps out prematurely, I'm not sure what to do. The Facet I had on it just was too much for the system, even on a pressure regulator. A bit stuck for ideas.
Holley 390 + SU fuel pumps.
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If I remember correctly the SU pumps used a spring behind the diaphragm to provide the effort during the delivery stroke, the solenoid stroke was used to restore the spring pressure.
If I am right you could remove the spring and reduce it's coils or height slightly giving you a lower working pressure.
jw
If I am right you could remove the spring and reduce it's coils or height slightly giving you a lower working pressure.
jw
Nige
Am I mising something but shouldn't a regulator solve this?
I had a silvertop facet pump that died on me in the first week.
I bought a red top and fitted a regulator to lower the pressure to 5 psi.
Did you have a gauge on the regulator to see the pressure?
I only have a bog std 3.5 but have no problems with this set-up.
Dave
Am I mising something but shouldn't a regulator solve this?
I had a silvertop facet pump that died on me in the first week.
I bought a red top and fitted a regulator to lower the pressure to 5 psi.
Did you have a gauge on the regulator to see the pressure?
I only have a bog std 3.5 but have no problems with this set-up.
Dave
