GM 19179576
Distributor Assembly

Look for Distributor Cap defects including cracks and holes or carbon track formation between terminals. Acceptable symptoms include normal discoloration and white buildup at terminals along with yellowed rotor caps and dark deposits at the rotor segment. Only replace parts if driveability issues exist. Professional intervention for a new cap and rotor installation should occur only when driveability problems emerge. To test for carbon tracks move an ohmmeter lead to a cap terminal while using the other lead to probe all secondary terminals and the center carbon ball; move the first lead between each terminal in sequence until all secondary terminals receive inspection; change the cap if non-infinite readings appear during testing. The process calls for cap replacement when non-infinite readings materialize during the testing procedure. Inspect the terminals of the cap for extreme corrosion while cleaning away the built-up material and plan for a new cap when corrosion threatens the component's structural integrity. If the rotor segment shows substantial wear it should be replaced because of its significant looseness. Detect shaft bushing looseness by placing the shaft into the housing to check for movement. The housing assembly requires replacement whenever the shaft shows any type of wobbling motion. Check the housing for any signs of damage or cracks as the last step of inspection. To diagnose ignition systems on vehicles running 5.0/5.7l engines utilize enhanced software found in computers and control systems- 5.0, 5.7l while the diagnosis software for 7.4l engines runs on computers and control systems - 7.4l.

To service and repair the Distributor, carefully disassemble it, labeling the Distributor driven gear, Distributor shaft, rotor holes for correct reassembly, as incorrect alignment causes a no-start condition and engine damage. Remove two screws fixing the Distributor Cap to the housing and throw them away, and then remove the cap off. Line up the white paint mark in the bottom of the stem of the Distributor with the pre-drilled indent hole at the bottom of the gear. Position the rotor segment appropriately for v6 engine or v8 engine ; if not, replace the Distributor. Next, take out the two screws holding the rotor in place, take out the rotor, and remember the locating holes. Loosen the two screws that are keeping the camshaft position (CMP) sensor and dispose off these screws, position the square-cut opening of the vane wheel facing the cmp sensor before pulling out the sensor. Note the dimple under the roll pin hole on one side of the gear for the orientation at reassembly. Support the Distributor drive gear in a v block and drive the roll pin from the point using a suitable punch and removing the driven gear off the Distributor shaft taking the round washer and tang washer with it and the round washer if included for the 7.4l engine. Remove the old oil seal. For assembly align the square-cut hole in the vane wheel for the cmp sensor and place the sensor in the housing, then apply 2 new screws and tighten them to 2.2n.m (20 lb in). Locate the correct rotor mounting at rotor screw holes & rotor locator pin holes and then install the Distributor rotor with reference to the index marks and tighten the rotor hold down screws to 1.9 n.m (17 lb in). If necessary, put the round washer into place for the 7.4l engine, then the tang washer over the bottom the Distributor shaft and the round washer. Mount the driven gear by index marks in line with the rotor along the marks for a v6 or v8 production, having the white paint off the bottom stem of Distributor mark lining up with pre-drilled indent hole on the bottom of the gear. If the driven gear is improperly installed, the dimple will be around 180 degrees from the rotor segment. Rep the expound to a distributary bobble gear in a v-nose and accept the tonnret pin by using a rightful punch and hammer to affix the driven cusp. Lastly, install the Distributor Cap to the two new screws that need to be tightened to 2.4 n.m (21 lb in) and the new oil seal at the mounting flange of the Distributor base.

If using a new distributor assembly, mark the new housing in the same locations as the original.