I need to change my fuel filter tonite on my wife's 88 IROC...since she has to leave for work tom. I have changed them before on my previous cars....etc. I cant remember the easiest way to relieve fuel pressure....the wire(s) or plug by the batt. or the plug above the fuel tank.????? Also, since the car is on ramps I have another question.....when I take off the old filter, I know some fuel will come out from being in the lines....BUT, since the car is elevated downward from being on the ramps...will the fuel keep coming out of the tank??? Or does the pump not let anymore go thru after you relieve the press?? Please forgive the ignorance....havent done this in a long time. I need some immediate help as the car is up on the ramps now....thanks in advance guys.....

 

I just remove the fuel cap. The official way is to pull the fuel pump relay & run the engine until it dies. You are always going to have some fuel run out, but it wont drain the tank as long as the pump is not running.

 

Thanks Rick, Ive always heard you could do that with the cap...but wasnt sure. Thanks again......

 

The oil pressure switch bypasses the fuel pump relay, so disconnecting the FP relay isn't going to do anything for you.

The only way to kill powet to the fuel pump without turning off the ECM too is to disconnect the connector by the tank in the back. And since you're already laying under the back of the car to do the FF anyway, it's no big deal.

And yes it takes a couple minutes for pressure to go down running it like this.

And yes fuel will syphon out constantly when you disconnect the fuel filter. Be ready to operate fast.

 

Thanks Ed....I got it last nite....it was like changin the coolant temp sensor or the knock sensor...lol I had to work fast. I dont think I lost that much fuel. Car runs MUCH better now. Thanks guys for all the help.....

 

Just disconnect it and forget about taking pressure out of the system.

 

I have done this many times on several different GM vehicles including my 87 Z & 00 Silverado. After the intial few ounces drain out of the line, that's it, no siphoning action with the cap off.

 

Wouldnt that cause fuel to spray out? Im going to change the filter on my 91 LT1 Z in a few hours.....I wasnt so worried about my wifes car as it has the original pump. But, my car has a brand new Walpro pump....much stronger than the old stocker. Im thinking I should disconnect the plug above the tank and let it run until it dies.....would that be sufficient?? I just dont want to get sprayed with fuel....its really not fun..lol

 

1. You can siphon the tank dry. Happened on my 86. Dont know why, it never did it before.

2. Yea, fuel will leak/spray out. Get yourself a shop towel and wrap it around the line. It'll just about saturate the towel, and thats about it. No big deal IMO. Been there, done that too many times to count. Also the pump you have doesnt matter, the line pressure is the same. Thats what you are dealing with, not volume.

 

ok thanks guys. Just wanted to make sure before I blew myself up..lol