de-pressurizing fuel system

Mustang_289 · 01-23-2002, 07:52 AM

I want to install a new fuel filter and I need to de-pressurize the fuel system.. The chilton's manual says to hookup a hand vacuam/pressure pump and apply pressure to the fuel regulator which will blow back into the gas tank to relieve pressure.

I do not have a hand vacuam/pressure pump do you guys know of some other way to relieve the pressure without buying the pump?

MustangDanny · 01-23-2002, 08:49 AM

If you don't mind being a little messy... just get an old rag and bunch it up right by the valve right behind you alternator (looks like a tire valve stem). Then with a long, small screw driver push the valve in to release the pressure. Some gas will spill out (that's what the rag is there for). This is what I did when I changed my fuel pump/filter.

cyberstang5.0 · 01-23-2002, 08:54 AM

I know this will work for Mustangs 87 and up.... ( I did it to my 92 and my friends 01)

There is a fuel pump shut off switch in the rear of the car. It is on the driver side for the fox body's and 99-02 models. I am assuming it's the same for the 94-98 models. It's is hidden in the plastic stuff right behid the tail lights inside the trunk. They have this so if a person read-ends you, the fuel automaticaly shuts off.

There is a little red round button on the top of it. Start the car and keep it in park/neutral. Then trip the switch. This will cut off the pressure from the pump to the engine. The car will die a few seconds later.

Unscrew the gas cap and that will releave any pressure in the tank. Gasoline weighs 7lbs per gallon so make sure that you run the car's gas as low as possible before you do this. If you make the gas inside as light as possible, it will make the job that much easier.

After you install the pump, don't forget to reset the switch and put the gas cap back on. Prime the car. All you have to do for that is turn the key like you are going to start it but don't. You will be able to hear the fuel pump wine. You should be all set.

fiveohpatrol · 01-23-2002, 10:36 AM

he's just putting a new filter in, so the tank can stay in place

You dont really NEED to de-pressurize the system. I changed about 30 fuel filters over the summer at a Ford dealer and never released the pressure. A little gas will spill out, but just cover your eyes and you'll be ok.

But if you insisit on doing it, just unplug the inertia switch that cyberstang was talking about, then start the car. After it uses the remaining fuel in the lines, the car will die. Change the filter, plug it back it, hit the button on it to reset it and start it back up.

hope this helps

cyberstang5.0 · 01-23-2002, 10:44 AM

OMG!

I must be dislesic. I thought he was going to replace his fuel pump. My bad! Sorry about that...

Mustang_289 · 01-23-2002, 10:48 AM

Thanx guys - I'm just replacing the filter!

Stang Runner · 01-23-2002, 10:49 AM

de-pressurizing fuel system is a good Idea and should Take at the most 45 sec just unplug the inertia switch was talking about, then start the car. I would DO it fiveohpatrol Dont know what he is talking about I HATE gas in the Face!!!!!!!!!!!!

fiveohpatrol · 01-23-2002, 11:11 AM

What is it with the guys on here trying to make other people look bad lately?

I DO know what I am talking about, I just said that it isn't completely necessary to de-pressurize the system. I've done plenty and didn't get one drop of fuel in my face.

Yes it takes very little time, but the reason I never did it is because I already had the car on a lift doing other things and it was easiest just to pull the lines and replace it.

you can do it whichever way you like Stang Runner, but don't tell me what I do and do not know

01-23-2002, 07:52 AM	#1
Mustang_289 Registered Member Join Date: Sep 2001 Posts: 512	de-pressurizing fuel system I want to install a new fuel filter and I need to de-pressurize the fuel system.. The chilton's manual says to hookup a hand vacuam/pressure pump and apply pressure to the fuel regulator which will blow back into the gas tank to relieve pressure. I do not have a hand vacuam/pressure pump do you guys know of some other way to relieve the pressure without buying the pump?

01-23-2002, 08:49 AM	#2
MustangDanny Registered Member Join Date: Nov 2001 Location: Dover, DE Posts: 70	If you don't mind being a little messy... just get an old rag and bunch it up right by the valve right behind you alternator (looks like a tire valve stem). Then with a long, small screw driver push the valve in to release the pressure. Some gas will spill out (that's what the rag is there for). This is what I did when I changed my fuel pump/filter. __________________ -- -1991 LX 5.0 Sedan, 5 spd (new 'Z' tranny), 3.73, aluminum DS, Hedman headers, 190 LPH, MAC CAI, Flowmaster catback. (170K miles on motor) Best ET: 14.434 @ 96.04 MPH - 2.205 60' (Radials) My Notch

01-23-2002, 10:36 AM	#4
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	he's just putting a new filter in, so the tank can stay in place You dont really NEED to de-pressurize the system. I changed about 30 fuel filters over the summer at a Ford dealer and never released the pressure. A little gas will spill out, but just cover your eyes and you'll be ok. But if you insisit on doing it, just unplug the inertia switch that cyberstang was talking about, then start the car. After it uses the remaining fuel in the lines, the car will die. Change the filter, plug it back it, hit the button on it to reset it and start it back up. hope this helps __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

01-23-2002, 10:49 AM	#7
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	de-pressurizing fuel system is a good Idea and should Take at the most 45 sec just unplug the inertia switch was talking about, then start the car. I would DO it fiveohpatrol Dont know what he is talking about I HATE gas in the Face!!!!!!!!!!!! __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

01-23-2002, 11:11 AM	#8
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	What is it with the guys on here trying to make other people look bad lately? I DO know what I am talking about, I just said that it isn't completely necessary to de-pressurize the system. I've done plenty and didn't get one drop of fuel in my face. Yes it takes very little time, but the reason I never did it is because I already had the car on a lift doing other things and it was easiest just to pull the lines and replace it. you can do it whichever way you like Stang Runner, but don't tell me what I do and do not know __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

01-23-2002, 08:54 AM	#3
cyberstang5.0 347ci of HORSE POWER!!! Join Date: Jul 2001 Location: Houston, TX Posts: 1,416	I know this will work for Mustangs 87 and up.... ( I did it to my 92 and my friends 01) There is a fuel pump shut off switch in the rear of the car. It is on the driver side for the fox body's and 99-02 models. I am assuming it's the same for the 94-98 models. It's is hidden in the plastic stuff right behid the tail lights inside the trunk. They have this so if a person read-ends you, the fuel automaticaly shuts off. There is a little red round button on the top of it. Start the car and keep it in park/neutral. Then trip the switch. This will cut off the pressure from the pump to the engine. The car will die a few seconds later. Unscrew the gas cap and that will releave any pressure in the tank. Gasoline weighs 7lbs per gallon so make sure that you run the car's gas as low as possible before you do this. If you make the gas inside as light as possible, it will make the job that much easier. After you install the pump, don't forget to reset the switch and put the gas cap back on. Prime the car. All you have to do for that is turn the key like you are going to start it but don't. You will be able to hear the fuel pump wine. You should be all set.

01-23-2002, 10:44 AM	#5
cyberstang5.0 347ci of HORSE POWER!!! Join Date: Jul 2001 Location: Houston, TX Posts: 1,416	OMG! I must be dislesic. I thought he was going to replace his fuel pump. My bad! Sorry about that...

01-23-2002, 10:48 AM	#6
Mustang_289 Registered Member Join Date: Sep 2001 Posts: 512	Thanx guys - I'm just replacing the filter!

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