when i start this motor for the first time i have no clue where the fuel pressure will (or should) be at. to adjust it obviously you have to pull the vacuum line, should this be done before the motor starts?

can you even adjust the fuel pressure with the car running or does it has to be off??

 

i really dont think it matters i drove for like 9 months with no vac. hose on it.

 

If nothing else, set it to stock fuel pressure (42-45 psi). You can set it by putting the key into the accessories position, it will be the same as if the engine was running with the vac line plugged.

 

The reason fuel regulators are vacuum referenced is to maintain a constant pressure differential across the injector.

Less vacuum, more vacuum, it is referenced to keep the fueling the same in both situations.

Without running a referenced regulator on a port type setup, most conventional ecms in our day we have it seeing more lean under throttle.

Its a good idea to keep t vacuum referenced.

later
Jeremy

 

so i can set it without the motor running then just hook the vacuum line back up??

 

thats probably true but i had the fuel pressure set at 52 and it never ran lean if anything to rich but its safer that way i would check the plugs see how they were and go about my day