Single Point Injection
This system is a continuous flow, single point, fully electronically controlled system. A single system electronically monitors the ratio of air to fuel and compares it to an ideal ratio by adjusting it automatically to changing environmental and engine conditions. This system also provides an integrated and pre-programed computer that commands ignition timing, monitors air/fuel ratio and emission control systems. The system also has the ability to update its programing to suite the current engine operating conditions, as required.
The computer has been programmed to monitor various component systems. If a malfunction of a system occurs, a fault code will be stored in the computer. If the problem is repaired or corrects itself, the computer will erase the code after 20 to 40 vehicle starts.Mult-Point Injection
This fuel injection system is made up of an electronic fuel injection and spark advance control system. The multi-point fuel injection system uses an injector for each cylinder, where the single point fuel injection system has one injector that is positioned in the throttle body assembly. With the multi-point fuel injection system, fuel is pumped to the fuel rail by using an electric fuel pump that is mounted in the fuel tank. The injectors are secured to the fuel rail with lock rings. The rail and the injector assembly is bolted in position with the injectors inserted in the recessed holes of the intake manifold. The fuel rail takes the fuel from the fuel pump and distributes it to the injectors, the injectors then atomize the fuel and spray it into the air entering the individual cylinder combustion chambers.
The computer has been programmed to monitor various component systems. If a malfunction of a system occurs, a fault code will be stored in the computer. If the problem is repaired or corrects itself, the computer will erase the code after 20 to 40 vehicle starts.
The fault codes can be read using diagnostic readout tool C-4805 (or equivalent) or through the Power Loss/Limited lamp. If a fault code appears, perform a careful visual check of all vacuum lines and electrical connections before doing any repairs to the system. The diagnostic read-out tool can be used to check out two other problem modes. They are the circuit actuation test mode and switch test mode. The circuit actuation test mode is used to analyze various systems. The switch test mode is used to test various switch circuits.Diagnostic Mode
- If available, connect Diagnostic Readout Box tool C-4805 or equivalent, to the diagnostic connector located in the engine compartment near the passenger side strut tower.
- Start the engine if possible. Cycle the transmission selector and the A/C switch if applicable. Shut off the engine. Cycle the ignition switch three times within five seconds.
- Record all the diagnostic codes shown on the readout tool or Power Loss/Limited lamp. Codes can be read from the Power Loss/Limited lamp by counting the number of flashes. For example, a code 35 would be three flashes, a pause, then five more flashes.
Code description is as follows:SINGLE POINT FAULT CODES
MULTI-POINT FAULT CODES
Circuit Actuation Testing
- Put the system into diagnostic mode testing and wait for code 55 to appear on the test screen. Press the ATM button on the diagnostic tool to activate the display.
- If a specific ATM test is desired, hold the ATM button down until the desired test code appears.
- The computer will continue to turn the selected circuit on and off for as long as five minutes or until the ATM button is pressed again or if the ignition switch is turned OFF .
- If the ATM button is not pressed again, the computer will continue cycling the selected circuit for five minutes and then shut the system off. Turning the ignition switch OFF will also shut the test mode off.
Code description is as follows:
Switch Testing Mode
- Put the system into diagnostic mode testing and wait for code 55 to appear on the test screen.
After code 55 appears, actuate the following component switches. The digital display must change its numbers when the switch is activated and released:
The computer will automatically erase the code(s) after 20 to 40 vehicle starts after the problem has been repaired. The code(s) may also be erased manually by disconnecting the negative battery cable for 30 seconds.