Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
3.3L Achieva, Grand Am & Skylark
1992 Saturn SC StandardSECTION 3.3L Achieva, Grand Am & Skylark
- Verify basic fuel system is okay. See BASIC FUEL SYSTEM CHECKS . Ensure TPS scans less than 2.5 volts. If TPS does not scan less than 2.5 volts, see code 21 in appropriate TESTS W/CODES article in ENGINE PERFORMANCE. If engine is cold, coolant temperature (CTS) should scan close to ambient air temperature. If coolant temperature does not scan close to ambient air temperature, see codes 14 and 15 in appropriate TESTS W/CODES article in ENGINE PERFORMANCE.
- Disconnect all injectors and install test light (J 34730-2A or equivalent) in an injector connector. Crank engine while observing test light. Test light should blink as engine is turned over. Test should be performed at one injector connector per bank. If test light lights as specified, go to step 5). If test light does not light as specified go to next step.
- If test light does not light at all on one or both banks, go to next step. If test light comes on solid, turn ignition off and disconnect black ECM "C-D" connector. Turn ignition on and note test light again at each injector bank. If test light turns off, ECM is faulty. If test light is still on solid, repair short to ground in Dark Blue or Dark Green wire between injectors and ECM. See Fig 1.
- Remove injector test light and turn ignition on. Using a regular test light, probe Pink/Black wire at injector connector to ground. If light does not light at every injector, repair open or short to ground in Pink/Black wire. If test light is on at every injector connector, go to step 9).CAUTION: When installing fuel pressure test guage, use a shop towel to absorb any fuel that may leak at fuel rail test fitting.
- Turn ignition off. Install fuel pressure guage. Turn ignition on and record fuel pressure reading after 2 seconds. Turn igniton off and repeat to ensure that all air is bled from fuel pressure guage. If pressure is 41-47 psi (284-325 kPa), go to next step. If fuel pressure is not as specified, see BASIC FUEL SYSTEM CHECKS .
- Check for spark using tool J 26792 (ST 125), or equivalent, at cylinder numbers 1, 3 and 5 plug wires, while cranking engine. Test is to be performed with cylinder numbers 2, 4 and 6 plug wires still connected. If there is no spark on all three wires, connection at ignition module poor, or ignition module faulty. If there is spark on only one or two wires, go to next step. If there is spark on all three wires, go to step 8).
- Check resistance of spark plug wires is less than 30k Ohms. Replace if necessary. If wires are okay, removed affected ignition coil and connect test light between two exposed terminal on ignition module. Test light should blink when cranking engine. If light blinks, repair poor connection between module and coil, or replace faulty ignition coil assembly. If light does not blink, replace igniton module. Primary coil resistance should also be checked. Primary coil resistance should be .5 - .9 Ohms. Replace as necessary.
- Disconnect injector connectors and measure resistance between terminals of each injector. Resistance of all injectors should be within .8 Ohms of each other. If resistance varies more than .8 Ohms, allow vehicle to cool to room temperature and retest. Replace any injector that does not measure between 11.8 and 12.6 Ohms at room temperature. If all injectors are okay, test IAC valve. See IDLE CONTROL SYSTEM in I - SYSTEM & COMPONENT TESTS article. If IAC valve is okay, inspect vehicle for mechanical faults and repair as necessary.
- Turn ignition off and disconnect ignition module 14-pin connector. Turn ignition on. Probe ignition module harness connector terminal "M" (Pink/Black wire) with a test light to ground. If test light turns on, go to next step. If test light does not turn on, repair open in Pink/Black wire or ignition fuse (20 Amp).
- Disconnect all injectors and turn ignition on. Hook test light to battery voltage. Install injector test light in any injector connector. Repeatedly touch test light to ignition module connector terminal "C" (Purple/White wire). Injector test light should blink. If injector test light blinks, go to next step. If injector test light does not blink, go to step 13).
- Turn ignition off. Rteconnect igniton module connector. Disconect dual crank sensor connector, and turn ignition on. Measure voltage between terminals "C" (Grey/Red wire) and "D" (White/Black wire) of dual crank sensor harness connector. Approximately 10-12 volts should be present. If voltage is as specified, go to next step. If voltage is not as specified, malfunction is due to poor connection at module, open or short in Grey/Red or White/Black wires, or faulty ignition module. Repair or replace as necessary.CAUTION: Keep hands and wiring clear of engine belt and pulleys during the following step.
- Turn ignition off and disconnect #6 spark plug wire from spark plug. Install spark tester (J 26792 (st125)) or equivalent to plug wire. Install injector test light in any injector connector. Jumper dual crank sensor connector terminals "A" (Light Blue/White) and "B" (Dark Blue/White). Connect a test light to ground. With igniton on, engine off, momentarily touch test light probe to terminal "A" while observing injector test light and spark tester. A spark should occur, and injector test light should blink. If results are as specified, malfunction is poor connection at dual crank sensor, faulty dual crank sensor, or damage to harmonic balancer interrupter ring. If results are not as specified, Malfunction is poor connection at igniton module, or faulty ignition module.
- Turn ignition off and reconnect injector connectors. Disconnect black ECM "C - D" connector and turn ignition on. Measure voltage between connector terminal "BC11" (Dark Blue) and ground, and between terminal "BC12" (Dark Green) and ground. There should be battery voltage at both terminals. If voltage is not as specified, repair open circuit in Dark Blue or Dark Green wire between injectors and ECM connector. If voltage is as specified, check for open or shorted Purple White wire between ignition module connector terminal "C" and black ECM connector terminal "BD8". Check for poor connection at black ECM connector terminals "BC11" (Dark Blue) and "BC12" (Dark Green). If all wires are okay, ECM is faulty.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.