2001 V70 N/A wont start after replacing fuel sender

[marsplex]

I had a gas leak, it was from the top of the fuel sender, i got the parts, unplugged the fuel sender on the left top side of the plastic tank, put the new gasket and a new black large black screw OEM parts from the dealer, i plugged the fuel sender back in now the car starts and instantly dies, Little to no fuel pressure at the rail. The previous owner said the fuel pump was new.

What am i doing wrong here? All i touched on this car was the fuel sender.

Anyone else have any clues or tips?

No codes, i used 2 different keys to try to start the car in case maybe it was an immobilizer issue

[oragex]

Immobilizer won't even crank. Was the car running upon purchasing it ?

[firstv70volvo]

I had a gas leak, it was from the top of the fuel sender, i got the parts, unplugged the fuel sender on the left top side of the plastic tank, put the new gasket and a new black large black screw OEM parts from the dealer, i plugged the fuel sender back in now the car starts and instantly dies, Little to no fuel pressure at the rail. The previous owner said the fuel pump was new.

What am i doing wrong here? All i touched on this car was the fuel sender.

Anyone else have any clues or tips?

No codes, i used 2 different keys to try to start the car in case maybe it was an immobilizer issue

A few questions to better understand the problem...
Did the car start and run okay before the work that was done to fix the leak?
Does the fuel gauge work when the ignition is at position II?
You say little to no pressure at the rail, did you measure the pressure with a gauge? If so is there any pressure? Is the fuel pump running?
Was there a fuel leak on the sender only side (not the pump side)? This would be unusual.
Does the car always start then die? If it always starts then I would think the fuel pump is running but pressure is very low.

I'm attaching the power path to the fuel pump in case it's not running. If you think the fuel pump may not be running you can check the fuse and also measure for power on pin 1 of the connector. You can also measure pin 4 to ground to see if this good (likely okay). Since the fuel pump is new doesn't mean it's good and may also mean there was a previous problem that's wasn't diagnosed or fixed correctly.

[marsplex]

Yes leak on sender side, car was running great. I unplugged and replugged in all the wires so many different times, unplugged and pulled the fuse, check relay, disconnect the battery then reconnected it and nothing would work. THEN suddenly it just started and now it's running fine so I have no idea what's going on but I did notice the fuel pump wasn't working during the time of no start condition then I heard the fuel pump prime and the car started out of the blue.

[firstv70volvo]

Yes leak on sender side, car was running great. I unplugged and replugged in all the wires so many different times, unplugged and pulled the fuse, check relay, disconnect the battery then reconnected it and nothing would work. THEN suddenly it just started and now it's running fine so I have no idea what's going on but I did notice the fuel pump wasn't working during the time of no start condition then I heard the fuel pump prime and the car started out of the blue.

So you determine it was the fuel pump not running causing the die after starting problem, which is good to know. Because it's an intermittent problem though and you didn't determine the exact cause you know this could happen again and it's not a problem you want to have on the road.

The problem started when you replaced the gasket and cover so I would first suspect the wiring or connector first but it could also be the new pump. Is there anyway to contact the previous owner to find out why the pump was replaced? Were there similar start and die or stalling symptoms prior to replacing the pump and the new pump didn't really fix the problem or was it replaced for a different reason? You could also trying moving the wires around some while the pump is running to see if there's any interruption in the pump running due to bad wiring or a poor contact in the connector. This is a problem where you really need to find the root cause since it's a safety issue out on the road if it happens again. Normally I wouldn't recommend replacing parts without knowing root cause but in this case if you can't determined the exact cause I would error on the side replacing everything; pump, sending unit, relay and fuse.