The 93-97 optispark distributor commonly malfunctions on higher mileage vehicles or if you get it wet. Some people notice immediate problems with the optispark after washing their engine.
You will start with disconnecting your negative battery terminal.
Then remove all the intake tubing, elbow, maf, etc.
Then remove your ICM bracket along with the coil (they are connected as one) which is held by two nuts/bolts [14 or 15mm] along with the ground wires). Of course, unplug all of the connections going to the coil and ICM prior to removing them.
[red dots indicate the two bolts and blue dots indicate plugs/straps that need to be removed]
Drain coolant from drain plug located at the bottom of the radiator.
Remove all hoses connected to the water pump and kinda push them aside. Now is where the fun starts.
Remove the water pump by removing the 6 bolts (9/16 deep socket). Driver side should take a few minutes to get the 3 bolts out, and the passenger side should take longer. One of the bolts on the passenger side in right behind the AC pump pulley, so in order to get it out, you will need a swivel-head to get in there,and by removing the belt (takes likes 1 minute), it would be a hell of a lot easier to get to. You may have to get underneath the car for some of this stuff (removing 2 of the water pump bolts, removing the belt, etc.). When you get the water pump off, make sure you don’t lose the sleeve that connects the drive gear from the water pump to the drive gear on the cam. The connector will be on either side, just don’t lose it.
Now comes the opti.
First you will have to remove the balancer (crank pulley- 5/8 bolts) using a puller that you can buy from advanced auto parts for like $30 and return it for a full refund when you’re done.
Once you remove the pulley, it’s pretty straight forward. If you have a vented opti, remove the two hoses going to the opti, then disconnect the optical plug very carefully so you don’t snap the clip (GM gets expensive with stupid little plugs like that).
Once you do that, label all of your spark plug wires (using duct tape or something), remove them from the opti and begin removing the (3) 10mm bolts.
If you have a 93-94 it should be just a gear on the back of the opti with a little notch. If that’s the case, make sure you line up that notch with the notch inside the timing chain cover.
If it’s a 95+ car/opti, the cam dowel has to be lined up with the oval on the opti.
Connect vacuum lines, optical plug, wires, and put everything back on.
Now do everything you just did backwards and put it all back together (Don’t forget to scrape off the old gasket off of the water pump housing). Make sure you put RTV sealant on the water pump gaskets (to stick onto the pump) and also apply it on the water pump bolts)
Install water pump (bolts should be torqued at 31 ft/lbs) and connect all hoses.
Install the Harmonic balancer (bolts should be torqued to 75 ft/lbs) and put the belt back on
make sure you connect all the ground wires/straps when installing the ICM/coil bracket on to the head.
Fill cooling system using your preferred coolant (I use straight distilled water with a bottle of water wetter and water pump lubricant – runs a bit below 180 for me), and DON’T FORGET TO BLEED THE SYSTEM via the two bleeder screws