How to relieve fuel pressure on 91?

I have a fuel injected '91 and I want to replace the fuel filter. I looked it up in my Haynes and it said to remove gas cap, negative battery cable and in order to relieve the fuel pressure you have to use a pressure guage, (except you remove the guage portion) and hook the hose up to the check port on the fuel rail. So, basically it is just a hose w/ the correct fitting for the valve and it just drains the fuel that's in the system. Autozone doesn't rent pressure guages, so I'd have to buy one and it's $37 - kinda a waste just so I can change my filter. Is there another way? Could i just loosen the filter and let the fuel drain form there? I know I have the potential to get soaked in fuel this way, but I don't think my system holds pressure that well anyway b/c it takes long to start unless it was just run.

I just removed the filter. I put a rag around the lines so it didn't spray everywhere.

yeah you can just remove the filter, just make sure you don't get any in your eyes, sometimes it squirts pretty good.


if you really want to "relief" the pressure, open the hood and look at the fuel rail. towards the #1 #2 fuel injector, there is a little black plast cap on a fitting on the fuel rail.....if you unscrew that cap, you can gently stick a screw drive in there......basically like letting air out of a valve stem......

WARNING: IF RELIEVING THE FUEL PRESSURE IN THAT LOCATION WILL SPRAY FUEL.........COVER EYES, AND DON'T DO IT WITH A HOT ENGINE.

FUEL IS FLAMABLE, SO CAUTIONG NEEDS TO BE USED WHEN WORKING AROUND IT.


incase anybody is going to flame me, yes i typed that in caps, and yes i typed a well known warning.........but i'm not going to give advice about spilling fuel near and engine and have somebody burn themselves alive and then try to say i didn't warn them.

scorpio_vette said:

if you really want to "relief" the pressure, open the hood and look at the fuel rail. towards the #1 #2 fuel injector, there is a little black plast cap on a fitting on the fuel rail.....if you unscrew that cap, you can gently stick a screw drive in there......basically like letting air out of a valve stem......

Click to expand...

Yeah, that's what they referred to in the Haynes. I think I'll just remove the filter - the Jeep has been sitting for a few hours now, so it's probably lost quite a bit of pressure, so I think I'll be safe w/ just that. Good to know that I don't have to keep the $37 guage.

gone postal said:

Yeah, that's what they referred to in the Haynes. I think I'll just remove the filter - the Jeep has been sitting for a few hours now, so it's probably lost quite a bit of pressure, so I think I'll be safe w/ just that. Good to know that I don't have to keep the $37 guage.

Click to expand...

if you are talking about a fuel pressure gauge and you work on all your own problems with your jeep, then just hold on to it, you'll need it eventually.

I clamp off the line to the filter with needlenose vise grips, and just take off the filter. It never made sense to me to say you should avoid dripping a little fuel on the ground by squirting it onto the engine instead.

Matthew Currie said:

I clamp off the line to the filter with needlenose vise grips, and just take off the filter. It never made sense to me to say you should avoid dripping a little fuel on the ground by squirting it onto the engine instead.

Click to expand...

I think the object is to avoid getting gasoline on myself or my clothes while I am under there. Plus, I try to squirt it into a cup or bottle and return the few ounces of fuel to the tank but I'm stingy like that. $$ I also empty the gasoline from the clean (outlet) side of the filter and return it to the tank.

I just removed the filter and used a large bowl to catch the gas. It wasn't more than a cup or two, so no big deal.

I have a '94 and I used the fuel rail method to bleed off the pressure. I think the '93 - '96 used this method-or I thought I read that in the Haynes Manual. I did however cover each end of the filter as I removed clamps and such to keep it out of the eyes-I WOULD WEAR SOME SAFETY GLASSES OR GOGGLES AT LEAST, since sometimes the dirt around that area can get in the eyes, then you can't see that you're spilling fuel all over the place---that sucks.

Jeff