2008 ForTwo odor, chasing fuel leak (bad fuel pump)

Disconnected battery. I loosened the hose clamp & disconnected the fuel filler hose at the fuel tank. I then siphoned most of the gas from the tank. Removed the 5 screws securing the tank, driver side rear screw removed last, eased the fuel tank down onto a couple 2x4s (to not overstress the fuel lines) on the floor. Left it under the car. Visually I saw nothing obvious wrong. Disconnected the outer fuel-return hose connection from the pump, saw no fuel, no obvious issue. Reconnected that hose. Decided to try powering-up the fuel system to see exactly where it leaks, expecting fuel under pressure to start leaking. Fire extinguisher handy. I turned on the ventilation fan blowing rearward, reconnected battery, turned key to ON position, looking carefully… no leaks. Cycled the key OFF then ON several times, no leaks. Turned key to START, let engine run about 60 seconds then OFF, continuously watching the fuel pump hose connections, no observable leaks. Disconnected both fuel pump hose connections, some fuel under pressure sprayed out for a moment from the center hose. I can’t see a problem with either hose or fuel pump connection - pump connectors appear structurally strong.

It’s puzzling. I really expected to see an active leak somewhere at the pump. All I did at first was disconnect & reconnect the return line hose. Had that been the leaking connection that was resolved when I mechanically refreshed that connection? I’ll revisit this again in the morning. I may have to put some fuel back into the fuel tank & let the engine run for a while (probably an hour) to be confident the leak is resolved. Feeling lucky I don’t have to chase a $200+ fuel pump, at least not yet. Update tomorrow.

This morning I reconnected the fuel pump electrical connectors & hoses, sealed the fuel tank fill port using a baggie & rubberband, turned on the fan to blow air rearward from the front of car (for cooling as well as ventilation). I tilted the fuel tank to put more fuel in the fuel pump end of the tank. Turned on the key to pressurize the fuel lines, no leaks. Started the engine & my stopwatch. Watched continuously for a fuel leak. Engine began to sputter then ran out of gas after 15 minutes, not a single leaking drop observed.

I guess my next step is to add a couple gallons of gas, re-orient the gas tank flat, try running it again for an hour, watching for a leak.

I'm not too impressed with a fuel connection that can be so easily disconnected by depressing a spring-loaded catch. It opts for quick & easy versus the security of time-proven hose clamps. I'd happily replace both fuel hoses if I could, just for connection insurance. Has anyone replaced fuel hoses?

I'll try the 60-minute run trial this afternoon. I'm open to any ideas about what else to consider now. Please add your $0.02, thanks.

I added a gallon gas to the fuel tank then resealed the tank, turned the ignition key ON, fuel is leaking at the main, pressurized fuel pump connector. There is a little play in the connection, I can slide that hose forward & backward at the pump connection, fuel squirts out with the slightest hose movement. There could be an unseen crack, but at this point I think the hose connector is bad. I base that on noting when I'd had both hoses off, I pushed / pulled on those pump hose connections gently, they were surprisingly firm. I guess I'll have to remove the remaining hoses & free the fuel tank from under the car to have a definitive look at the top of the pump.

Searching our archives, I can't find an instance where someone found & replaced a defective fuel line except for one instance where there's speculation the dealership may have damaged one during a fuel pump replacement. I think the hose in question goes directly to the fuel injector rail. Anyone ever replace a ForTwo fuel hose? The part# may be 451-476-1601 according to my local Smart Center.

If I conclude its the (weak-link) connector, I'll consider my repair options, like conventional fuel hose & hose clamps. Thoughts?