Okay. I have some answers for you. I have a '92 LeSabre, so it is very similar to yours.
First, are you certain that is the fuel pump fuse? I ask because on my '92, the fuse and the fuel pump relay are under the hood in the fuse/relay block. It may be that on a '90 model, there is no fuse/relay block under the hood. So I will assume you are right, and that is the fuel pump fuse.
So there is only one fuse, and here is how the power goes: the fuse is "hot at all times", meaning it has a direct battery connection. The power goes through the fuse and to the Fuel pump relay. It is the power feed for this relay. When your pcm signals this relay with a current signal, the relay is energized and power goes through the relay and directly to the pump in the tank, on a gray wire.
Now you have a short, blowing this fuse. It is a break in the wire, or possibly a shorted out fuel pump. This might help" Unplug the connector at the gas tank, put a new 20amp fuse in the fuse slot, and turn the key to on. You can go ahead and even crank the engine over for a couple of seconds. Now see if the fuse has blown again. By havng the key on, you have sent power all along the gray wire to the gas tank. If there were a short in the wiring, the fuse will blow out. Then you know the short is in the wiring before the gas tank in the circuit. Try to follow the wiring harness from the relay to the tank, or maybe you will want to just run a new wire from the relay to the connector at the tank. That is IF the fuse got blown by turning key on and cranking engine over.
If the fuse does not blow, with tank unplugged and engine cranking over, that means the problem short must be in the pump itself. Put the rear end of the car up on blocks, or jack stands, and pull the tank off and replace the pump. Not very expensive, be careful, the real cheap pumps are junk. Buy an AC Delco or Delphi brand pump (about $65), the engine will run much better with one of them.
So you know: with key on-not start, the pcm signals the relay to turn the pump on for 2 seconds to prime the system. If key not turned to start, pump will shut off and hold pressure in the lines for several minutes. As soon as key is turned to " crank", the pcm again signals the relay and pump is turned on for as long as the engine is cranking. When the engine starts, another switch called the oil pressure switch is spliced into the gray pump wire, and when there is oil pressure in the engine, there is also power being sent to the fuel pump to keep the pump running. This is just so you know. you have a short in the circuit, and it is not that complicated of a circuit.
Go to autozone dot com and make a free account, put in the vehicle make model and year and look for the free repair guides.
20 AMP is a big fuse, I would say its the fuse to the motor check this web site http://www.beijing-fanyi.com/1990/1990-buick-lesabre-wiring-diagrams
SOURCE: upon replacing my fuel pump fuse (15amp)and
Pretty sure you need a new fuel pump, it may be shorting out inside or seizing up drawing too much current blowing your fuse. There easy to change, if you need info on R & R a fuel pump get back to me.
SOURCE: Fuel relay placement 1991 Buick LeSabre. Replaced pump & filter still won't start
Your vehicle's fuel pump relay is located on the relay center, behind the glove box, 2nd column of relays, 2nd one from the top.
SOURCE: fuel pump fuse blowing
replace the fuel pump, it is drawing to much current, this is common when the pump bearings get worn out, also make sure you replace the fuel pump connector at the fuel tank connection, it will be burnt..
SOURCE: Starter is dead.
Hi,
It does sound like a starter shorted out on you. You can remove the starter and have it checked... I think Autozone will do it for free. Plus if you needed a new starter, they'd want a core exchange anyway and you'd already have it in hand. Don't forget to disconnect your batery before you begin this operation!
Hope this helped... Good luck!
Testimonial: "The subtle comment about disconnecting the battery was a helpful reminder. Also, I was unaware that Autozone did this for free. Thanks!"
SOURCE: Intermittent fuel pump engagement when turning key - 2001 Taurus
try cleaning the connector that goes to the fuel pump, sometimes they corrode on inside. If that does not fix, test the wires feeding fuel pump with a multi meter until the condition shows itself again, if voltage drops to zero or very low then wiring problem, if voltage is unchanged with problem and fuel pump is not working and connectors are all clean, try replacement of fuel pump.
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