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Fuel Pump Question
https://www.slantsix.org/forum/viewtopic.php?t=44726
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Author:  Omni Source [ Mon Apr 25, 2011 6:04 pm ]
Post subject:  Fuel Pump Question

Good Evening All

While troubleshooting the 64 Dart for a fuel related issue, I checked the fuel pump pressure (stock mechanical pump).
The factory service manual calls for 3.5 to 5 lbs.(The Dart was 4.5) It also says that when the motor is turned off the fuel pump pressure should either remain constant or drop very slowly. The Dart will drop to '0' in about a minute.
The car runs now idles and runs well. (18"vacuum at idle in park)Should this be an area of concern or just leave it be.
If the pump should be replaced, any particular brand?
Thanks to All
Omni

Author:  4speed [ Mon Apr 25, 2011 6:09 pm ]
Post subject: 

It's fine. A one min bleed down is ok. It may get better with use if the car was sitting for awhile.

Author:  SlantSixDan [ Mon Apr 25, 2011 7:43 pm ]
Post subject: 

Some of the slant-6 pumps are reported to have an internal bleed passage to drop the pressure off quickly after shutdown, which greatly reduces hot start/hot idle problems by dint of reduced tendency to percolate. I don't know if this is actually so; I haven't collected a pile of original \6 pumps, operated them and taken data on bleed-down time. But I do know the factory offered an anti-flooding kit for Dodge trucks with slant-6 engines, consisting of tiny passages, one on the inlet and one on the outlet of the fuel pump, connected by a short piece of small-diameter hose. These tiny fittings had a (literal) pinhole, that was all. The setup bled off vapour bubbles during hot engine operation and bled down the fuel pressure rapidly on shutdown. It helped.

As long as your fuel pressure comes up quickly when you crank the engine from cold, leave it be.

(What was the solution to your hot idle low vacuum and fuel load-up?)

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