'99 Suburban extremely hard on fuel pumps

[j cAT]

since the return line being squeexed did not show any pressure increase I would say you did not squeeze it enough becausw it should have moved somewhat. therefore place guage on the fuel filter . key on eng will be off see what the pressure goes to should be over 75 psi and hold for a few min at the high pressure. using steel repair lines or the nylon and steel to complete the line repair is up to you the steel lines are cheaper. using compression fittings and the steel with a bender not too hard about 30 USD or so... surprised 1 yr old filter and it was rusted solid.. perhaps you need better wrenches.. the real bitch will be the quick disconnects at the front/top of the fuel tank/canister .. these with rust and grit are tough to remove.. I did do my return line and supply line in this area recently. then I used a rust preventive on all these metal lines ..

[Joe Bltsphlk]

I removed the pump from the tank. There was a lot of debris inside the "cup" that the pump sits in. Check out the photo. It was a mixture of fine particles and some bigger rusty ones. The "internal" sock looked like it was clogged up. The fuel tank itself did not have any of the debris. My theory is that the return line is starting to rust on the inside, and the debris is getting carried back into the fuel pump where it gets trapped in the cup. The pinhole leaks in the tank are much smaller than some of the debris, so I don't think they are the source. I cleaned out all the debris, and my plan is to see if the pump can still be used.

I was going to replace the fuel lines with Goodyear fuel injection hose SAE 30R9, but tech support at summitracing said you're not supposed to run flexible line for the entire length of the vehicle, because it will result in too much pressure drop. So I'm looking at NiCopp rather than steel, because there are so many bends. My question is how exactly do I get it to mate up with everything else. For example, it seems like all Dorman connectors are for nylon tubing, like part 800-080. At the fuel filter connection, do I use a compression fitting to Dorman 800-153?

[j cAT]

I would replace the return line most of it with the nylon. one long piece. use loom to protect where needed. then on the ends use the nylon to steel adapters. use plastic tystraps/raps to secure this line to the old bending is not a problem and this is a faster way .. you still have a tank with rust holes this is not good.

steel tanks/steel fuel lines are not good with this ethanol fuel. nylon can take the supply pressure easy. I would not use rubber hoses not good with alcohol and other gasoline additives and injectors ... rubber is bad idea..back in the non alcohol era it was ok..