We bought a 98 Saturn SL2 we had a full diagnostic done while doing the smog and everything. We ended up replacing the fuel pump. Over the next 8 weeks the pump has been replaced 3 times and the fuse once. Now the service engine light is on and we were told it is the solenoid. Shouldn't this have shown up in the diagnostic? Or would it have gone out with all the changes of the fuel pump?
There's lots of solenoids for all different things. Parts fail all the time. There's no way of knowing when that will happen and there's no reason for something to show up as defective before it has broken. If that were the case, every part on the entire car would have to be replaced because they're going to fail or wear out sometime in the future.
As for repeat fuel pump failures, Chrysler had a lot of trouble with that years ago. Their pumps were built to very tight clearances to make them quiet, but they got plugged up from microscopic debris in the tank. Each time the pump was replaced, more of that debris got "collected" in it until it stopped working. By the fourth or fifth pump, people got frustrated and bought one from the dealer and didn't have any more trouble. In fact, it wasn't that the pump came from the dealer. It was that all the debris was gone. NAPA buys their Chrysler pumps from the same supplier that Chrysler buys them from, so they're just as quiet and just as likely to plug up. The proper fix was to have the tank steam cleaned at a radiator repair shop when installing a new pump. Mechanics who did that had no repeat pump problems.
As for the blowing fuse, it's possible the new pump is locking up, but given the recent history, it's more likely the wire going to the pump is rubbed through and shorting intermittently causing what APPEARS to be a pump failure but is really a wiring problem.