Your fuel filter will be basically inside the frame rail under the driver's seat (or somewhere close). It is in front of the fuel tank. The box you are talking about is the EVAP canister.

About that fuel pump... I would be very skeptical as to whether it would work. If you are feeling adventurous, go for it, but it will require modification of your sending unit for it to be used. I love the last comment in the page - "can see better fuel consumption"...? That's good! Is the guy comparing fuel consumption from when the car wasn't running due to a faulty fuel pump? LOL

 

Very good point on that last commenter, Kyle! Didn't think about it that way...

I consider myself an adventurous guy, but not when it comes to repairs that require removing the gas tank. I want it to work right the first time. LOL

So do you think my best bet is to go with a stock GM part? Does GM make a performance version of the stock part? For that matter, would a pump designed for a 350 work in a 4.3 Vortec?

 

Tanks are different. Fuel pumps very rarely max out and are continuously circulating fuel through the system. At some point if you were to max out the stock pump, I would recommend you install an auxilliary inline fuel pump, but not until you have the need.

As far as I know, there are no GM performance pumps available. I would recommend an AC Delco pump though.

 

Okay, Kyle. If I need a pump, I'll take your advice and get the stock AC Delco. Thanks again.

 

Hello Everyone , This is my first post so i hope i do ok for all of you and any help on posting will be appricated.
I have a 95 blazer with simular fuel psi problems. I have changed the cpi spider and nut kit because of a leaky FPR . What made me change it was ,the blazer was very hard to start at first than wouldn't start at all and looking inside i could see washing on the passenger side around the FPR and the fuel pressure was low 40 to 45 psi. and drop to around 20 psi with key off. The confusing part was sometimes it would hold and othertimes it would not. After installing the spider and nut kit and supply lines,i reconnected the fuel pressure tester and found that i still had the low fuel pressure. There was no leakage from the installed parts so i put the thing back together and decided to check the fuel filter and pump .I put a test gauge on the supply line before the filter and found the same psi 40-45 psi. I than reconnected the supply line and figured its the pump. Just to see if it might be a voltage dropand after reading about it here, I ran a direct 12 volt feed to the pump test lead under the hood driver side and found that if i intermittentlytapped the wire to the voltage source( battery positive side ) I could bump the pressure upto63 psi. I cannot bump the psi up by bumping the key to on.
At the first crank of the engine at 63 psiit would try to start but the pressure would drop instantly to 45 to 50 psi. . At the low psi I could get it to start using starting fluid.
The pump runs when i turn the key to on , i hear the relay in the glove box click
and once running i show 55 psi fuel pressure while the engine is running and it runs real smooth. Anyone one have thoughts why i can Bump the pressure up to 63psi and the pump won't do it normally. I'm really not wanting to have to drop the tank yet and i would like to cover all the bases.

 

This sounds like a problem with voltage drop to the pump which could be from corroded connections or broken wires. However, it could also mean that your pump is toasted and needs higher voltage to start correctly, but once its warmed up and running off of alternator voltage (>13.5V), it runs fine.

How far does your battery voltage slip to when you try to start your truck?

 

Hello : Last night i bumped the pressure up yo 63 psi and decided to call it a night . this morning the fuel pressure gauge had droped to 20 psi . I will be checking the voltage that you suggested in an short time. I did however connect on of those portable battery jumpers you can buy .i connected it to the direct feed to the pump, the pump starts but needed to be bumped to 60 psi.I than kept the pump running and tried to start it and again it dropped to 45 psi. does the pump have a check valve in it ? just asking , but i think the pump must be the bad egg.

 

So you needed to start and stop the pump a few times to get the pressure to 63PSI? Is that correct?

And yes, there is a check valve in the pump that holds pressure in the lines.

 

yep yes

 

This definitely sounds like a failing fuel pump. You should not have to bump start it for it to reach is maximum working pressure.