Fuel pressure and fuel flow?

[carlospena96]

Hello,
I need to know what is the fuel presseure and fuel flow of the OE fuel pump on a FI fiat spider?
I put a mercedes benz fuel pump, but the car don't go more than 3.5 - 4k rpm

[RRoller123]

OEM fuel pump output pressure is 39-45 psi.

Regulated pressure in the rail is 33-39 psi at the CSI.

Factory manual page 10-106.

[carlospena96]

and the fuel flow? the fuel pump of the mercedes benz is about 2.7 l per minute

[RRoller123]

No idea on the flow data spec

[DieselSpider]

and the fuel flow? the fuel pump of the mercedes benz is about 2.7 l per minute

2.7 liters per minute is 162 liters or 42.79587004 gallons per hour so that should be plenty of flow. At how many psi is it able to deliver 42.79587004 gallons of fuel per hour or enough fuel to drive over 1,000 miles at 25 mpg?

[carlospena96]

I guess you are wrong with that, the flow keeps the fuel on the injectors at high rpm with the same pressure, thats why depending on your car and fuel injection (or carburator) you need more or less flow

[DieselSpider]

But at what pressure? It has to meet that pressure requirement and then the excess fuel flows from the fuel rail back to the tank. You have to meet that specification and the best tell is with a fuel pressure gauge at the fuel rail to see if your pump is up to meeting that requirement. You may have a tired or defective used pump there so regardless of the original specs of the Mercedes pump a current pressure reading of whats going on with it installed and the car running at idle and at speed will be your best tell. If the pressure at the pump is less than 39 psi at speed then you have a defective or undersized pump if it is 39 to 45 psi at the pump but not between 33 to 39 psi at the rail at speed then you may have a defective regulator or may be needing a new fuel filter.

[sptcoupe]

Hmmm. Why not just put a FIAT fuel pump on it?