Routing of the Spark Plug Wires for a 1989 5.7 GMC 1500

The 1989 GMC C/K 1500 trucks were equipped with an optional 5.7-liter V-8 engine, more commonly called the 350. The spark plug wires carry spark from the distributor to the spark plugs on the 1989 C/K 1500 trucks. Proper spark plug wire routing is essential to the ignition timing on a vehicle.

Instructions

1

Open the hood on the truck. Disconnect the negative battery cable from the battery using a ratchet and socket. Go to the passenger side of the engine compartment. Familiarize yourself with your distributor cap. Read the "Tips" section below to better understand your engine and distributor cap wire orders.

2

Match the old spark plug wires from the engine as you remove them, with a wire of the same length from the new set of wires. If you do not have the new set of wires, you will have to judge the new wires as you install them. Install the No. 8, 4, 3 and 6 wires onto the passenger side towers of the distributor cap, in that order from front to rear. Install the No. 1, 2, 7 and 5 in that order on the cap, in that order from front to rear.

3

Set the No. 2 and No. 3 wires across the distributor cap so that they are lying on the side of the engine that they are going to be installed on.

4

Route the No. 8 spark plug wire to the rear of the engine and install the wire into the bottom groove of the wire clip on the rear side of the valve cover. Wrap the wire around to the bottom groove of the passenger corner clip, then install the wire on the rearmost spark plug.

5

Route the No. 6, 4, then 2 wires in the same manner. Fill the wire clips from bottom to top with the wires, then lock the clips. Route the No. 4 and 2 wires to both the two-wire clips on the outboard side of the valve cover, from bottom to top. Lock both of the two wires clips. Install the three remaining passenger spark plug wires onto their spark plugs. Push all four spark plug wires onto the plug until they click and lock into place.

6

Route the No. 7 spark plug from the cap directly to the support clip on the valve cover. Route the wire to the corner support clip bottom groove, then to the spark rearmost spark plug. Route the No. 5, 3 and 1 wires in that order, in the same manner. The No. 1 and 3 spark plugs are held in two additional clips toward the front of the engine. Route the No. 5 and 7 wires on the outside of the metal EGR tube alongside the exhaust manifold. Route the No. 1 and 3 wires inward from the EGR tube.

7

Push all four spark plug wires onto their spark plugs until they click and lock into place. Route the ignition coil wire from the coil to the center post on the distributor cap. The ignition coil is the cylindrical device directly forward from the distributor cap.

8

Install the negative battery cable onto the battery and tighten it snug with your ratchet and socket.