The engines have 2 timing belts: One belt is the acceleration timing belt that drives the camshaft from the crankshaft. This belt also drives a balance shaft that must be correctly timed to avoid engine vibration (more on this below). The second belt, inboard of the timing belt, is the drive belt for the oil pump and a second balance shaft. Although this belt usually does not break, it should be replaced whenever the timing belt is replaced.
Tools Needed
The following tools are needed as a minimum:
Floor jack.
Jack stands.
Metric combination wrenches: 10mm, 12mm, 14mm, 17mm.
Slotted & Phillips screwdrivers.
Wheel lug wrench.
Now the procedure is as follows:--
Park the car on a level surface. Raise the front off the ground and secure with jack stands.
Remove the drivers side front tire/wheel.
Remove the plastic panel inside the wheel well. This panel is secured to the chassis with some 12mm head bolts up in the wheel well and along the front radiator cross-member. There are also some plastic push fasteners that look like Phillips screws: Unscrew and pull out the plastic screw, and then pop the plastic retainer out of the panel. Keep the panel and hardware together and set aside.
Place a floor jack under the engine oil pan. Make sure you place it so that it does not damage the pan, or put some rags between the two. Raise the jack enough the support the engine.
Remove the drivers side engine bracket. There are 2 (14mm) head nuts on the forward side, and 2 (14mm) head bolts at the other end of the bracket. Once unbolted, remove the 2 nuts securing the engine mount through-bolt to the chassis, and remove the through-bolt after removing its (17mm) retaining nut. Keep all this hardware with the bracket as you pull it out and set it all aside.
Loosen the tension on the alternator, power steering pump and air conditioning compressor belts.
Remove the water pump pulley from the water pump by removing the (4) 10mm head bolts.
Remove the harmonic balancer/pulley from the crankshaft by removing the (4) 10mm head bolts.
Remove the air conditioning belt tensioner bracket/assembly on the 2.0 engines by removing the (3) 12mm attach bolts.
FOR more detailed help:--
Mitsubishi Eclipse 1998 Repair Guide 
Engine
REMOVAL & INSTALLATION

Relieve the fuel system pressure.
If not already done, disconnect the negative battery cable.
If equipped, remove the engine under cover.
Matchmark the hood and hinges and remove the hood assembly. Remove the air cleaner assembly and all adjoining air intake duct work.
Drain the engine coolant into a suitable container, then remove the radiator assembly, coolant reservoir and inter-cooler. 
If equipped with AWD, remove the trans axle and transfer case. 
Tag and detach the following components: accelerator cable, heater hoses, brake vacuum hose, connection for vacuum hoses, high pressure fuel line, fuel return line, oxygen sensor connection, coolant temperature gauge connection, coolant temperature sensor connector, connection for thermo switch sensor, if equipped with automatic transaxle, the connection for the idle speed control, motor position sensor connector, throttle position sensor connector, EGR temperature sensor connection (California vehicles), fuel injector connectors, power transistor connector, ignition coil connector, condenser and noise filter connector, distributor and control harness, connections for the alternator and oil pressure switch wires.
If equipped, with A/C, remove the A/C drive belt and the compressor. Leave the A/C lines attached. Do NOT discharge the system. Wire the compressor aside.
Remove the power steering pump and wire aside.
Remove the exhaust manifold-to-head pipe nuts. Discard the gasket and replace with a new one during installation.
Attach a hoist to the engine and take up the engine weight. Remove the engine mount bracket. Remove any torque control brackets (roll stoppers). Note that some engine mount pieces have arrows on them for proper assembly. Double check that all cables, hoses, harness connectors, etc., are disconnected from the engine. Lift the engine slowly from the engine compartment.
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