This repair manual covers the following Buick, Oldsmobile, and Pontiac automobiles, 1970 through 1990:
- Buick: LeSabre, Estate, Electra, Limited
- Oldsmobile: Delta 88, Royale, Custom Cruiser, Ninety-Eight Luxury, Regency, Brougham
- Pontiac: Catalina, Grandville, Brougham, Bonneville (1970-1981), Parisienne, Safari
Note: this manual does not include diesel engine info., FWD models, turbo models or 4.3L V6 information.
Book Excerpt: 1970-1990 Buick, Oldsmobile, Pontiac Full-Size Models Repair Manual
ENGINE ELECTRICAL SYSTEMS
IGNITION COIL | CHECK AND REPLACEMENT
EMISSION CONTROL SYSTEMS
- If the engine is hard to start (particularly when it's already hot), misses at high speed or cuts out during acceleration, the coil may be faulty.
First, make sure that the battery and the distributor are in good condition, the points (pre-1975 vehicles) are properly adjusted and the plugs and plug wires are in good shape.
If the problem persists, perform the following test:
BREAKER POINTS IGNITION SYSTEM
(Refer to illustrations 11.3a and 11.3b)
- Before performing any of the following coil electrical checks, make sure that the coil is clean, free of any carbon tracks and that all connections are tight and free of corrosion.
Also make sure that both battery terminals are clean and that the cables are securely attached (especially the ground strap at the negative terminal).
- Detach the coil high tension cable from the distributor cap. Using an insulated tool, hold the end of the cable about 3/16-inch away from some grounded part of the engine turn the ignition on and operate the starter.
A bright blue spark should jump the gap.
- If the spark is weak, yellowish or red, spark voltage is insufficient. If the points, condenser and battery are in good condition, the coil is probably weak.
Check the coil primary and secondary resistance (see illustrations).
Refer to the Specifications listed in the beginning of the Chapter. If the coil windings are damaged the resistance will be excessively high. Replace the coil.
- If there is no spark at all, try to locate the trouble before replacing the coil.
Remove the distributor cap. Turn the engine until the points are open, or separate the points with a small piece of cardboard.
Turn on the ignition switch. Using a 12-volt bulb with two test leads, attach one lead to ground somewhere on the engine and the other lead to first one of the coil's primary terminals and then the other.
TRANSMISSION CONTROLLED SPARK (TCS) SYSTEM
- This system is designed to eliminate the vacuum advance at the distributor under certain driving conditions. The system is incorporated on certain models through 1974 and on all vehicles with manual transmissions.
The Transmission Controlled Spark (TCS) system used for 1971 models is also known as the Combination Emission Control (CEC) system.
- Vacuum for the advancing mechanism in the distributor is shut off until the transmission is in High gear or 3rd and 4th gears with the 4-speed transmission.
Vacuum is allowed in Reverse for the Turbo Hydra-Matic automatic transmissions.
- This system is made up of: a transmission switch; engine coolant temperature switch; time delay relay; vacuum advance solenoid; and an idle stop solenoid.
Although this system is somewhat more difficult to service, check and maintain than the other emissions systems, when each component is examined individually the operation of the TCS system can be easily understood.
- On manual transmissions, the electrical switch is actuated by the internal shifter shaft. The switch is located on the outside of the transmission case, adjacent to the shifter shaft.
- Automatic transmissions use a pressure-sensitive switch which is actuated by the fluid pressure as the transmission reaches High gear (and Reverse in the case of the Turbo Hydra-Matics).
This switch is located on the outside of the transmission on Powerglide and Turbo Hydra-Matic 350 transmissions. Turbo Hydra-Matic 400 transmissions have the switch mounted internally in the transmission.
- When activated in the proper transmission gears, the switch sends an electrical input to the vacuum advance solenoid. This TCS component remained basically unchanged through the four years in which it was used.
Subject: 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985 1986, 1987, 1988, 1989, 1990 Buick, Oldsmobile, Pontiac Full-Size Models service, maintenance, repair. ISBN-10: 1563922479 | ISBN-13: 9781563922473 | Haynes 19025