System Wiring

Fig. 9 "Weather Pack" Terminal Repair:

Fig. 10 Wiring Harness Repair:

Fig. 11 "Micro-Pack" Terminal Replacement:

Due to the electronic system control and low system voltages, certain precautions must be taken to ensure accurate diagnosis and avoid system damage.

*** THIS PROCEDURE HAS BEEN UPDATED BY TSB #87-T-4, Dated 9/86
The need for the technician to wear special static reducing equipment such as a wriststrap or grounding mat is recommended. This will prevent the possibility of (ESD) electro static discharge damage to electrical parts. Also recommended:

1. Do not open package until it is time to install the part.
2. Avoid touching electrical terminals of the part.
3. Before removing the part from it's package, ground the package to a known good ground on the vehicle.
4. Always touch a known good ground before handling the part. This should be repeated while handling the part and more frequently after sliding across the seat, sitting down from a standing position, or walking a distance.


Do not disconnect or connect electrical connectors with ignition on unless specifically instructed. Do not connect test equipment directly to ECM, except where noted, and never attempt to measure oxygen sensor output as sensor will be damaged.

Due to low system voltages, special weather resistant connectors and wiring harnesses are used in most parts of the TBI system. If wiring and/or connectors are diagnosed as defective, special repair procedures must be followed. Damaged molded connectors must be replaced by splicing a new connector into the harness. Damaged "Weather Pack" connectors can be repaired as shown, Fig. 9. If "Weather Pack" terminals are damaged or bent, or if connector housings cause terminal misalignment, they must be replaced. Terminals should only be removed from "Weather Pack" connectors using tool No. J-28742 or equivalent. Use of any other type tool may deform the terminal or housing, and unlike standard blade-type terminals, these terminals cannot be straightened.

If damaged or defective, engine compartment wiring harness must be replaced with an exact replacement. However, single wires can be repaired as shown, Fig. 10. Use only wire of the proper gauge with high temperature insulation. To ensure the best possible bond at wire splices, all connections must be soldered.
If ECM connectors are equipped with "Micro-Pack" terminals and connectors are damaged or defective, refer to Fig. 11 for replacement procedures.

Before repairing or replacing any TBI system component diagnosed as defective, check wiring harness connections as follows:

1. Disconnect electrical connectors from component and check for bent, broken or dirty terminals and mating tabs.
2. Clean, straighten or replace terminals and connectors as needed.
3. Reconnect electrical connector and repeat test procedure.