You might want to print out the following, to review with your mechanics teacher before he looks at the car. He might be familiar with Bosch Fuel and Ignition systems, but your Regina FI and Rex Ignition work the same way. Likely suspects (based on car age) are:

• Crank Position Sensor (a $30 item, mounted in top of bell housing)
• Radio Suppression relay (Allows +12V to injectors, with ground side being ECU controlled)
• Fuel relay
• Failing Fuel pump (in tank)

Start Sequence Analysis

1) During starter cranking, the Crank Position Sensor sends timing pulses to Ignition ICU.

2-a) The ICU propagates these timing pulses to the Power Stage (aka Ignition Amplifier) to initiate spark at the coil.

2-b) The ICU also propagates these pulses to the FI ECU, to allow FI operation
(no ICU pulses means no FI operation).

3-a) The FI ECU energizes the Fuel Relay, which has two outputs (3-b and 3-c below).

3-b) Fuel relay sends power to fuel pumps,

3-c) and also powers AMM, IAC, ECU, and Injectors (via Radio Suppression Relay)

Given these three events, the engine runs until the Ignition is switched off, which in turn shuts down the FI system.

Determining whether or not there is spark at the plugs (2a) —and whether or not the plugs are getting gas (3c)— will allow some analysis of this sequence.

For example, if 2a fails due to a bad Power Stage/Amplifier, there will be a no-start with gas-wet plugs. If 2b fails (practically never) symptoms will be Fuel-related: a no-start with spark at the plugs, but plugs remain dry.

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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.