EXPERTEC TSB (T85-108A)

Publication date: 1985-08-05
Reference number: T85-108A

EXPERTEC TSB

TECHNICAL SERVICE BULLETIN

Reference Number(s): T85-108A, Date of Issue: 08/05/85

INTERMITTENT RICH OPERATION - ERRATIC TCC OPER. CODES 15/38

Model(s): 1980 Cadillac Eldorados and Sevilles with 6.0L DEFI Engine

1981 Cadillac Fleetwood Broughams, De Villes, Eldorados and Sevilles with 6.0L DFI Engine

1981-84 Cadillac Limousine with 6.0L DFI Engine

1982-85 Cadillac Fleetwood Broughams, De Villes, Eldorados and Sevilles with HT4100 DFI Engine

1983-84 Cadillac Cimarrons

1985 Cadillac FWD Fleetwoods and De Villes with HT4100 DFI Engine

1985 Cadillac FWD Limousine with 4.1L DFI Engine

Bulletin No.: Cadillac T85-108A

Date: 08/05/1985

SERVICE INFORMATION

This bulletin supersedes 85-108, Group 6E, which should be destroyed.

Some 1980-1985 vehicles with fuel injection may experience intermittent rich operation, black smoke during restarts, erratic Torque Converter Clutch engagement and disengagement, and/or ECM diagnostic codes 15 or 38. These conditions can result from an open circuit or excessive resistance in the Manifold Air Temperature (MAT) and/or coolant sensor circuits. These conditions can be diagnosed by using diagnostic engine data display parameters P.O.4 and P.O.5. Display parameter P.O.4 (coolant temperature) and observe the parameter while an assistant moves or manipulates the coolant sensor wire harness connector. An open circuit condition will cause the coolant temperature to read an unrealistically low temperature (i.e., 0 deg. C, -38 deg. C etc.). Repeat this procedure with parameter P.O.5 (MAT). An open circuit in the MAT circuit will also result in an unrealistically low temperature reading. The coolant temperature should not vary rapidly under steady throttle conditions.

To correct the above conditions, it is necessary to replace either the MAT sensor and MAT connector or the coolant sensor and coolant connector with Metri-Pack type connectors.

BULLETIN ILLUSTRATION LIST

Fig 1: Graphic

Fig 2: Graphic

Fig 3: Graphic

Fig 4: Graphic

Fig 5: Graphic

Fig 6: Graphic

PARTS INFORMATION

The following part numbers are required to equip a vehicle with the new Metri-Pack connectors.

PARTS INFORMATION

Part Name	Part Number
Coolant Sensor	25036708
Coolant Sensor Wire Harness Kit	12046623
MAT Sensor	25036751
MAT Sensor Wire Harness Kit	12046624

To replace the MAT and coolant wire harness connectors, refer to the attached instructions on wire splicing and soldering.

NOTE: The MAT and coolant wire harness connector wires must be spliced and soldered. Do not use solder less lock type connectors to secure the wires.

Coolant and MAT sensors with the old style connectors are still available from GMWDD. It is important to specify Metri-Pack type connectors if an intermittent problem is suspected.

SPLICING INSTRUCTIONS FOR MANIFOLD AIR TEMPERATURE (MAT) OR COOLANT

TEMPERATURE METRI-PACK WIRE HARNESS CONNECTOR SERVICE KIT

The Manifold Air Temperature (MAT) or Coolant Temperature sensor must be replaced when a MAT or coolant wire harness connector service kit is installed on a vehicle which does not have a Metri-Pack (flat connector pin) MAT or Coolant sensor. The sensors should be ordered using the following part numbers:

PARTS INFORMATION

Parts Number	Description
25036751	Coolant Sensor
25036708	MAT Sensor

SERVICE PROCEDURE

NOTE: Due to the very low currents in the MAT and coolant circuits, it is very important to solder the wire splice joints to ensure good electric conductivity.

STEP ONE: OPEN THE HARNESS

If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores).

If the harness has a plastic conduit, simply pull out the desired wire.

STEP TWO: CUT THE WIRE

With the wires pulled out of the plastic conduit, cut the first wire at least three inches into the conduit to ensure that the splice will be protected by the conduit. Cut the second wire 1 1/2 inches further into the conduit, or 4 1/2 inches from the end of the conduit.

STEP THREE: STRIP THE INSULATION

If you aren't sure of the wire size, start with the largest opening in your wire stripper and work down until you get a clean strip of the insulation. Be careful to avoid nicking or cutting any of the wires.

Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat the procedure on a new section of wire. The two stripped wire ends should be equal in length.

STEP FOUR: CRIMP THE WIRES

Locate the clip contained in the service kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the two stripped wire ends and hold them between your thumb and forefinger as shown (see Fig 1 ). Then, center the splice clip under the stripped wires and hold it in place.

Open the crimping tool to its full width and rest one handle on a firm flat surface.
Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip.
Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes (see Fig 2 ).

Before crimping the ends of the clip, be sure that

The wires extend beyond the clip in each direction,
No strands of wire are cut loose, and
No insulation is caught under the clip.

Crimp the splice clip again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wire (see Fig 3 ).

STEP FIVE: SOLDER

Apply 50/50 rosin core solder to the opening in the back of the clip as shown (see Fig 4 ). Follow the manufacturer's instructions for the solder equipment you are using.

STEP SIX: TAPE THE SPLICE

Center and roll the splicing tape. The tape should cover the entire splice.

Roll on enough tape to duplicate the thickness of the insulation on the existing wires (see Fig 5 ). Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness (see Fig 6 ).

STEP SEVEN: REINSTALL WIRE IN CONDUIT OR RETAPE HARNESS

WARRANTY INFORMATION

For warranty purposes use the following labor operations and times when installing Metri-Pack type sensors and connectors:

T6127 - Replace Coolant Sensor and Coolant Connector 80 E/K - .7 Hr. 81 C/E/K - 1.2 Hr. 82-83C, 84-85D - .5 Hr. 82-85 E/K - .5 Hr. 83-84 J - .7 Hr. 85C - .6 Hr.

T6129 - Replace MAT Sensor and MAT Connector 80-85 E/K - .5 Hr. 81-83C, 84-85D - .5 Hr. 85C - .6 Hr.