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Home >> Buick >> 1991 >> Regal V6-191 3.1L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Related Tests, Information and Procedures >> A Charts >> Chart A-3 Engine Cranks But Will Not Run >> Production Release After VIN 800,000 >> Part 1 of 3

Part 1 of 3

Chart A-3 Part 1 Of 3:




Chart A-3 Wiring Diagram:






*** UPDATED BY TSB # 92-6E-20 DATED AUGUST 1992

CIRCUIT DESCRIPTION:

This chart assumes that battery condition and engine cranking speed are OK, and there is adequate fuel in the tank.


TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. A MIL "SERVICE ENGINE SOON" light "ON" is a basic test to determine if there is a 12 volt supply and ignition 12 volts to ECM. No DLC, may be due to an ECM problem and CHART A-2 will diagnose the ECM. If TPS is over 2.5 volts the engine may be in the clear flood mode which will cause starting problems. The engine will not start without reference pulses and therefore the "Scan" should read rpm (reference) during crank.

2. For the first two seconds with ignition "ON" or whenever reference pulses are being received, PPSW should indicate fuel pump circuit voltage (8 to 12 volts).

3. Because the direct ignition system uses two plugs and wires to complete the circuit of each coil, the opposite spark should be left connected. If rpm was indicated during crank, the ignition module is receiving a crank signal, but no spark at this test indicates the ignition module is not triggering the coils.


4. The test light will determine if there is B+ at the injectors. The injectors are powered by a 10 amp fuse located in the right hand side underhood electrical connector.

5. This test will check the integrity of the ECM injector driver.

6. This test will determine if circuit 467 is open between the mini-harness connector and the the injectors.

7. This test will determine if the ignition module is not triggering the problem coil or if the tested coil is at fault. This test could also be performed by using another known good coil.

8. This test will determine if the ignition control module is not generating a reference pulse signal or if the ECM or wiring is at fault. By touching and removing a test light to 12 volts on circuit 430, a reference pulse should be generated. If rpm is indicated, the ECM and wiring are OK.
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