Carter HP 4601 pump pressure ???

[Broncman]

Running a carter pump and pressure has held at 15 psi...until it got cold. Temps have got into the thirties and guess the fuel has gotten thicker. pressure has went to about 20-25 psi.

Do these need external regulators?

[comotionman]

hey, yeah this sucks. thanks for responding to my thread. did not see your thread. never read anything about this before, maybe i did not look hard enough. this is probably why the oe lift pump is so low pressure. so when temps drop and the pressure spikes it is still within acceptable levels. is this info in a sticky somewhere that i overlooked? it should be included in the info for people that go to an aftermarket lift pump whether electric or mechanical that puts pressure much closer or right at the safe limit that colder temps cause pressure increases which mandate a regulator. i am also going to be adding a heater loop to my fuel tanks. got my regulator on the way, should have it friday. already have my hose nipples and in town now getting ready to get a bushing and plug for the extra port which i may use for a gauge later.

[Broncman]

I put my regulator on tonight. Limited it to about 13 lbs.