For the sake of completeness, here's the full no-start Troubleshooting Guide for the 2001 6 cylinder 3.5L MFI Mitsu Diamante, but the problem with your car is line item #6 - the ECC (Engine Control Computer) is shorted/dead. Without an ECC, the Diamante will (a) get no spark, since the ignition timing comes from the computer, and (b) get no fuel, since the fuel injectors are operated by the computer as well. The engine will turn over, since running the starter motor is a non-computer controlled matter of a correctly functioning ignition switch, a charged battery, and good wiring to a functional starter motor/solenoid, but will never start.
The clue pointing directly to the ECC failure is the blowing ECC fuses. These fuses are blowing to tell you that the ECC is shorted dead.
Since the ECC is expensive, exhaustively check out all other possible sources of the problems, but with so few problems causing loww of both spark and fuel, combined with the blown ECC fuses pointing directly to the ECC, it seems that the ECC is the only culprit.
Here's a used 2001 Mitsu Diamante ECC at Ebay for $175.http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=270828804340+&item=270828804340&lgeo=1&vectorid=229466
Priority Action Part Type Cause
1 Inspect Choke - Stuck or Improperly Functioning Choke.
2 Inspect Fuel Filter - Clogged or Dirty Fuel Filter.
3 Inspect Fuel Pump Relay - Faulty Fuel Pump Relay.
4 Inspect Fuel Injector Pressure Regulator - Faulty Fuel Injector Pressure Regulator.
5 Inspect Fuel Pump - Low Fuel Pressure.
6 Inspect Engine Control Computer - Incorrect Operating Information Being Delivered and Sent From The EEC.
7 Inspect Fuel Pump Strainer - Clogged or Dirty Fuel Pump Strainer.
8 Inspect Ignition Switch - Improperly Connected or Faulty Ignition Switch.
9 Inspect Battery - Battery Discharged or Faulty.
10 Inspect Battery Cable - Coroded, Broken, Shorted or Poorly Connected Battery Cable.
11 Inspect Solenoid - Starter Solenoid Faulty.
12 Inspect Starter - Starter Motor Faulty.
13 Inspect Wireset - Worn or Damaged Spark Plug Wires.
14 Inspect Ignition Coil - Faulty Ignition Coil.
15 Inspect Distributor Cap - Loose, Cracked or Worn Distributor Cap.
16 Inspect Spark Plugs - Incorrectly Gapped or Fouled Spark Plug(s).
17 Inspect Distributor Rotor - Loose, Cracked or Worn Distributor Rotor.
18 Inspect Fuel Tank - Fuel Tank Empty.
19 Inspect Carburetor - Worn, Faulty or Damaged Carburetor.
The fuel pump strainer is a sock-like strainer in the fuel tank on the input side of the fuel pump designed to protect the fuel pump by straining out any debris in the tank (similar to the way that the fuel filter protects the engine/fuel injectors/fuel pressure regulator).