Fuel Pump Pressure?

Swarzkopf1 · 08-31-2004, 08:50 AM

Tested the stock fuel pump in my 95 GT yesterday by connecting my fuel pressure tester to the test port on the fuel rail, and then turning the ignition to where I could hear the fuel pump priming and stopping it there. The car was cold and had sat overnight, so the system was depressurized from sitting.

The pressure gauge read 15 PSI. It held at 15 PSI, with no variation over several minutes. This seems awfully low to me.

Was this the correct way to check the fuel pump? This is how I was taught, but I was also under the impression that the fuel pump alone should be able to make ~30-40 PSI.

With the car running, the fuel pressure remained at my settings of 45 PSI vacuum off and 39 PSI vacuum on.

Should the fuel pump make more pressure on its own? Is it time to drop the tank and put a new one in?

Thanks.

GhOsT6_9 · 08-31-2004, 12:01 PM

With the car off my pressure is at around 15-20.

If with the car running the pressure stays at the 35+ psi under acceleration then you should be good. Unless you're running lean then you may need to bump your pressure up or get a bigger pump.

88fivepointoh · 08-31-2004, 01:57 PM

exactly what GhOsT6_9 said... if you getting good pressure when the car is on then your ok.. If you need to bump it up then do so.

Swarzkopf1 · 08-31-2004, 02:07 PM

Thanks for the feedback guys.

I won't make the fuel pump a priority at this point then.

Another reason I was concerned is that my fpr is turned close to all the way up, and my pressure is only 45/39...but I guess this would be normal for a stock pump.

I'll have to replace the pump in the next few months anyway, as I plan on spraying.

08-31-2004, 08:50 AM	#1
Swarzkopf1 Registered Member Join Date: Jul 2004 Posts: 18	Fuel Pump Pressure? Tested the stock fuel pump in my 95 GT yesterday by connecting my fuel pressure tester to the test port on the fuel rail, and then turning the ignition to where I could hear the fuel pump priming and stopping it there. The car was cold and had sat overnight, so the system was depressurized from sitting. The pressure gauge read 15 PSI. It held at 15 PSI, with no variation over several minutes. This seems awfully low to me. Was this the correct way to check the fuel pump? This is how I was taught, but I was also under the impression that the fuel pump alone should be able to make ~30-40 PSI. With the car running, the fuel pressure remained at my settings of 45 PSI vacuum off and 39 PSI vacuum on. Should the fuel pump make more pressure on its own? Is it time to drop the tank and put a new one in? Thanks.

08-31-2004, 12:01 PM	#2
GhOsT6_9 Registered Member Join Date: May 2000 Location: Ontario,Canada Posts: 233	With the car off my pressure is at around 15-20. If with the car running the pressure stays at the 35+ psi under acceleration then you should be good. Unless you're running lean then you may need to bump your pressure up or get a bigger pump. __________________ 1989 Mustang LX Notch 5.0L, T-5, 1969 351W heads, cut & welded stock plenum, F-303 cam, Mac 1 5/8 full length headers, Cat'd H-pipe, 3.73 gears, Underdrives, SSM lift bars, E-Fan, 3G Alt, Custom Chip, Autometer gauges, Weld Draglite wheels , M/T ET Street Radials Best 1/4: 13.33@101.53MPH

08-31-2004, 02:07 PM	#4
Swarzkopf1 Registered Member Join Date: Jul 2004 Posts: 18	!! Thanks for the feedback guys. I won't make the fuel pump a priority at this point then. Another reason I was concerned is that my fpr is turned close to all the way up, and my pressure is only 45/39...but I guess this would be normal for a stock pump. I'll have to replace the pump in the next few months anyway, as I plan on spraying.

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08-31-2004, 01:57 PM	#3
88fivepointoh Registered Member Join Date: Aug 2002 Location: Rochester Posts: 553	exactly what GhOsT6_9 said... if you getting good pressure when the car is on then your ok.. If you need to bump it up then do so.