Fuel Pump Replacement

[XWrench3]

well,i found the trouble. the fuel pipe came off from the top of the housing. i thought i might have trouble with that. because i could not get the pipe on very far. after immersing the pipe in boiling water for a few minutes, i finally got it on over the first barb. but that was as far as it would go. i was hoping that after the pipe hardened up from cooling, it would stay put. but i guess the pressure was just to much. now, i am not sure what to do. i cut the old line off from the top to make sure i did not break the fitting, which would render the housing useless. so i can not put that back on. and i can not force the new hose on all the way, even with heat. i know regular rubber fuel line would blow apart under that much pressure. any ideas???

[XWrench3]

oh, i forgot to mention, the hose fitting on the fuel pump itself, and on the top of the housing are 2 different sizes. the one on the top of the housing is larger. the fuel pipe that was included in the fuel pump kit has both ends the same size. which is why i heated the pipe up in boiling water, so it would hopefully stretch enought to fit.

[old_master]

Should be 3 lines on the top of the module all with quick connect fittings. Lube the O ring with engine oil and push them on until they click.

1/4" is fuel vapor going to vapor canister.
5/16" is fuel return from the regulator.
3/8" is pressurized fuel going to the injectors.

Post some pictures that show what line you're having trouble with. The pump kit that you bought... did it come in a box labeled "AC Delco"?

[XWrench3]

yes, it is a genuine ac delco pump kit. the problem line is the clear hard plastic line that connects the fuel pump to the top of the module INSIDE of the tank. the hose barbs on the top of the module are huge by normal standards, and i can not find a way to get the hard plastic to go over them. out of desperation, knowing that bad nasty weather is coming tonight, i purchased rubber fuel injection hose, and fitted it with clamps where the clear line goes. then put it back together and checked for leaks. it does now start and run, and holds 62psi on the gauge that i bought this morning at advance auto parts (THANKS for telling me about that!) the worry that i have is if the rubber hose will hold up in that environment. if nothing else, i hope it will make it to spring. i really hate laying in wet half melted snow, or 30 mph winds especially working in gasoline!

[old_master]

Gotta be sure it says "Fuel Injection Rated" on the line. No worries about being exposed to gasoline, it will not deteriorate BUT, what might be a concern is the "accordian" style clear plastic line is designed to bend without kinking when you push the spring loaded module down into the tank. If it's restricted, fuel flow will decrease and the pump will have to work harder which will shorten it's life expectancy.

Holding 62psi is great! What is the key on, engine off, fuel pressure while the pump is running?

[XWrench3]

yes, the line says right on it "fuel injection", i know regular line will burst around 25 pounds (don't ask me how i know). i did think about the line kinking, and tried it. it looked to me like it may restrict the flow. so, i measured the length between the pump and module hose barb when fully open. then i measured how far the module collapsed as i installed it into the tank, and shortened the hose that much. the result was i could just feel the bottom of the module hit the bottom of the tank with about the thickness of the circlip left. so the hose will have to compress whatever that thickness is. the 62 psi is with the pump hotwired with the engine off, and the battery fully charged and connected to the battery charger(10 amp). when i first start the pump, i can watch the pressure raise rapidly, and i can see the needle hit almost 70 pounds for just a half second or so until the pressure release valve opens. i let the pump run for about an hour like that as i finished up installing the fuel tank crash gaurd, and lowering the vehicle and taking care of tools. i wanted to make sure if there was going to be a problem, it would hopefully show up in the driveway before it left me stranded somewhere. i did not check the pressure while it was running. i know the pump has way more flow than the engine could ever use at max rpm wide open throttle. and since it takes wide open just fine, i can not imagine there is a problem there. now, i did not replace the filter, it was replaced this spring, and it probably has less than 3000 miles on it. the inside of the tank was cleaner than our kitchen floor usually is. so i really do not see a need to. i did notice one thing that i am not so sure about. i noticed that the pressure bleeds off from the rail. it is pretty slow, and it took probably an hour to get down to around 35 psi. since the pump runs for a few seconds prior to starting the engine, (i always wait till the pump is done running before starting the engine) i would think this is ok. please tell me if it is not!

[old_master]

Sounds like you did your homework on the line in the tank, should be good. GM does not publish any "engine running" fuel pressure specs for this engine, there are far too many variables involved.

Testing fuel pressure and leakdown: Ignition in the RUN position, engine OFF, (or hot wire the fuel pump). While the fuel pump is running, the fuel pressure must be 60psi to 66psi. After the pump shuts off, fuel pressure must remain above 55psi for at least 10 minutes. This checks a ton of stuff and if it meets those requirements, regulated fuel pressure to the injectors is good. There is also a volume test for the pump; it's rare that you'd ever perform the test though, usually the pump just takes a crap.

Allowing the pump to shut off before cranking is actually a good idea, (cuts down on starter wear). Tough to get into the habit, but if you're there, cool.

[XWrench3]

just something i picked up on with our first fuel injected vehicle. i figured if they wanted the pump to run before you started the engine, they had a good reason for doing so. and it only takes a few seconds, so why not start the engine after the system is primed and ready to go. in severe weather, it may mean the difference between the engine starting or not. especially if the battery has had a drain on it, or is weak. and who knows when that is going to happen, until you hit the key. my battery is less than 2 years old, so there should not be an issue with it.

[old_master]

It's a good habit to get in to.... turn the ignition switch to the RUN position, wait for the fuel pump to stop running, then turn the ignition switch to the START position. This allows the fuel pump to receive full battery voltage to prime the system.