Fuel Filter Replacement How-To-Write Up Discussion Thread - Blazer Forum

lennyblazer · #1 10-06-2007, 12:02 AM

This is a write up on how to replace your fuel filter. This goes for Second Generation 2wd, 4wd, 4dr, 2dr, and ZR2 Blazers. It may work for earlier vehicles, but maybe slightly different. The process is similar for most vehicles too.

Tools needed:
* 16mm open end wrench
* 15/16" or 21mm open end wrench
* 13mm socket
* Pliers (to squeeze front fuel line fitting off)

First step is to relieve the pressure in the fuel system. There are two ways to do this. Personally I would use the first method since it is easiest and cleanest.

1A Go under the hood and open the main fuse block. You will need to locate the fuel pump relay and remove it. See the pictures below:

Make sure you remember the direction that the relay goes into the fuse block. Next go try to start your truck and let the engine starve for gas. Once it will no longer turn on, the gas line pressure has been relieved.

OR

1B Go under the hood and find the Schrader valve located behind the air intake and throttle body (see picture below). Take a flat blade screwdriver and depress the middle portion of the Schrader valve, make sure to catch the gas that will fly out of the valve with a towel or cup. Once the gas stops coming out of the Schrader valve, the fuel pressure has been relieved.

Second step is to jack up or raise the front of the vehicle and place jack stands and chocks behind the wheels.

Third step is to start removing the nuts on the back side of the fuel filter. You will need two wrenches (a 16mm and 15/16" (or 21mm) open end wrenches). The larger wrench is just to hold the filter in place and then loosen the rear nut with the 16mm wrench. Once loose enough remove the rest of the way with your hand. Then be prepared with a container to catch the gas (a tin can from having canned vegetables works great).

Fourth step is to remove the fuel filter bracket bolt (13mm socket and a small extension). After that, pop the bracket loose from the fuel and brake lines above. Then pull the filter and front fuel line around the other side of the torsion bar and allow to hang down.

Fifth step is to use your hands to squeeze the plastic clips holding the filter onto the front fuel line and pull filter from the front fuel line (this will release a little more fuel).

Sixth step is to finish draining all the gas from the filter and then pry the bracket off of the old fuel filter. Next test fit the filter in the bracket. If it is super snug cut off some of the tangs inside the bracket then just push the bracket to the middle of the filter.

Seventh step is to reinstall which is the reverse of removing the filter. Once everything is back in place, reinstall the fuel pump relay under the hood. When going to start your truck, turn key to run position and allow the fuel pump to pressurize. Then try starting, it will take about 10 seconds for the engine to start and run properly, so dont worry if it doesnt start right up. Afterwords it should start right up like normal. On the initial startups check for fuel drips/leaks at the fuel filter. If there is a leak, turn off engine and make sure all fittings are tightened properly, then try it again.

Now you are all done and have a nice clean new fuel filter. Enjoy. Any questions PM me or post in the discussion section.

*Edit by swartlkk* - Fixing the clipping problem.

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muleman · #2 10-07-2007, 12:09 AM

pain in the butt... getting these off.... you can tell that these were put on the frame before the body was set on at the factory... changed mine and got sooo pissed... but awesome how to do this... props....

lennyblazer · #3 10-07-2007, 12:14 AM

Yeah it wasnt too bad, just had to figure out how to get the dang brake and fuel lines off the top of the filter bracket and to get the new filter into the bracket.

blazinloud · #4 10-07-2007, 11:25 AM

thanks for the how to. I'm sure it will be used lots.

blzR · #5 10-09-2007, 02:15 PM

I have Never in my fuel filter changing travels ever touched the "Main-Block-Fuses"..is this really a neccessary project within projects?..i only pressed the relief valve to relive pressure.

**rriddle3** · #6 10-09-2007, 02:17 PM

Pressure valve is my method, but someprefer to pull the fuse.

lennyblazer · #7 10-09-2007, 07:40 PM

If you pull the relay all you have to do is start the truck and it will stop running once the fuel pressure is relieved. It just makes it so you dont have to deal with spraying gas in the engine compartment. Either method works fine, and the relay is very easy to remove. Its all just personal preference, hence why I posted about both methods.

muleman · #8 10-10-2007, 04:54 PM

when i did mine i didnt know you had to rel. pressue on it... i just disconected it from the fuel line, and maybe 1/4cup came out not much at all, and it just dripped out no spay, but next time i will do it the right way..

**swartlkk** · #9 10-10-2007, 04:56 PM

The fuel test port on my Rainier is back at the filter. I installed my fuel pressure gauge (with bleed hose) and I had almost a pint of fuel come out. Still got some fuel out of it when I pulled the filter, but this filter is just two snap fittings and a single screw for the clamp. Quite easy to replace!!

lennyblazer · #10 10-10-2007, 11:37 PM

Yeah the blazer has been the easiest vehicle I have replaced a fuel filter on out of 6 vehicles (not all mine only 3). Yeah I was reading that the new trailblazer, rainer, envoy chasis setup had a very nice and easy location for removing the fuel filter and depressurising the fuel system.