I know how to release the pressure on the system,but how many lines are there to disconnect ? do you just pull them out ?? how are they secured ? what about electrical connections . Is there a thread that exdplains it all ?? I want to check the o-ring on the fuel pump seal at the tank Iam getting p0442 error code after having my fuel pumup replaced

 

I just helped a friend replace the fuel sending unit on a 1998 GMC Jimmy, which is obviously similar, but perhaps slightly different. On his tank (and in general) there are three smaller (~1/4") fuel connections going to the sending unit, an electrical connector going to the pressure sensor on the sending unit, and an electrical connector going to the sending unit pump itself. There was also a vent line (~1/4") attached to the far front of the top of the tank (this can be removed last after the tank is almost completely out as it is somewhat harder to get to, but the line has plenty of play). And then there is the fuel filler neck and filler vent hoses towards the back of the tank. The fuel lines have tabs on either side that you squeeze while pulling the line out. The tank is connected to the filler neck and filler vent with short lengths (~3") of hose. Theoretically you could undo the hose clamps and remove these hoses, but I think you will save some skin on your knuckles by just cutting this hose and replacing it. Note that the large diameter hose, we were only able to find at a NAPA store. The electrical connectors wires leading to the tank have a decent amount of play; however, if you are not replacing the sending unit, be very careful of the smaller fuel line connections. You must try to disconnect them as soon as you can get your hand above the tank. Dropping the tank any significant amount without unhooking these risks breaking the connections on the sending unit. If you are replacing the sending unit you can just pull the tank down without unhooking these lines and the sending unit part of the connection will break and then you can worry about unhooking them from the broken-off piece after the tank is removed (this is what we did and it worked well).

You will need something to prop up the tank after the restraints are removed, before you get all the connections undone.
I would put thispretty solidly in the category of '2 man job.'
Good Luck...

 

I would add that when we replaced the sending unit, we ended up reusing our old o-ring, as the new one was too hard and wouldn't allow the sending unit to be properly seated.

 

How is the sending unit with the o-ring secured ? is it a twist lock ?? I want to check the o-ring for a proper seal. Thanks for the info

 

There is a lock ring. The sending unitjust sitson top of the o-ring. The lock-ring then goes on top of a lip on the sending unit and underneath a lip that sticks up on the gas tank.

 

Do you think if you drop the tank a few inches it would be possible to unlock the sending unit and check out the seal withoutremoving the tank completly

 

If you can keep the tank supported properly, you should not have any issue doing so. However, you will likely still need to remove most of the connections to gain enough space...

 

Thanks again

 

It might be possible, but I think you'd have to have one of those 'mirror on a stick' tools so that you can see the lock-ring before/while you are trying to undo it. The real savings of this would be not having to reattach thefiller neck and filler vent hoses, but I'mnot sure it would be worth it depending on how long it takes to get theo-ring out without dropping the tank. Also I think it would be a challenging toget the sending unit and0-ring properly reinstalled without having the tank dropped.