so im about to finally change my fuel filter. but have no idea how to depressurize the fuel line. i have a 1996 GMC Jimmy 4.3 vortec. some places i read say fuse #9 or pull the fuel pump relay then try crank it. also i cant find a definite anwser what relay in the glove box is the fuel pump one.

 

This task isn`t hard at all.First of all unscrew the gas cap.I have an (haynes)repair manual.It says"To attach a fuel pressure gauge to the test port and open the valve to drain the excess fuel out of the drain tube into a gas safe small container.It really doesn`t have anything saying where the fuel relay is located.But I bought mine 5 months ago.The fuel filter was the first thing I changed.But only difference is that I knew where my relay was..It was under the hood.Another way to find out where the relay is?Take each one out till you find the correct relay.When you do find it will run for a few seconds than kill.While your at it, spray some W-D40 on the fittings.Also not sure if you have 2 metal gas lines or 1 metal line/1 plastic line.If you do have a plastic line,it has a clip on it.They make a special tool to release the clip.I didn`t have a tool so I just used a small screwdriver to break the clip off.I would advise you not to use a screwdriver like I did.I don`t want to get blamed for something if it breaks.Also make sure you have lots of rags,because you will have some gas coming out of the gas lines.After it`said and done.Reinstall the gas cap,turn the key on and off 3 to 4 times,but don`t start it right away.This will prime the fuel pump.After you start it..Look for leaks.

 

we are supposed to depressurize? i just wear glasses and hope for the best. but i just make sure the key is off, find the fuel pressure valve under the hood and push it to release the pressure and done. just make sure the engine is cool as some gas will come out

 

You don`t have to if you choose not to.It just helps keeping the gas from spraying all over you while your unlooseing the gas lines.

 

Another way to do it is to remove the fuel pump relay and turn the truck over.

 

He doesn`t know what relay is for the fuel pump.

 

Two more glittering examples of why to lose the Haynes manual, (they're worthless). #1. When you connect the fuel pressure gauge to the service port, that alone will depressurize the system. No need to open the valve, IF your gauge even has one, (not all gauges have them). Like abig84 mentioned, it will depressurize when you take the lines off the filter, use a drain pan to catch it. Better than spraying all over the engine and making a mess or starting a fire. #2. A GM factory shop manual will tell you right where each relay is. Pitch the Haynes in the trash where it belongs. Half of the information is wrong, (it's up to you to decide which half) and the other half is nonexistent.

 

Since the truck is not going to be driven, and just needs to de-pressurize the fuel pump, remove all the relays back there.. Simple as that. Once that is done, put relays back in once the job is done.


THIS!

The haynes manual is worthless. A true GM shop manual will tell you where everything is, You can find them on ebay all day long. I have even found people on craigslist with a full collection of them selling each year for GM.

 

Please don't quote a Haynes or Chilton manual on this forum. Someone could mistake it for technical information. The shop manual will pay for itself the first time you use it. I use my Chilton book on my lap when I eat soup so the bowl doesn't burn my legs.

 

The old school Chilton and Haynes manuals that were hard covered and around two inches thick were not too bad, not as good as a GM shop manual but still worthwhile with a large grain of salt - the new style soft cover excuses that you buy in the parts stores are not even good for John Wayne TP or rolling papers - Too slick for TP and burns way too harsh - save your twenty bucks and buy beer instead, at least you will have a worthwhile hangover when done