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Hal
Hal, Chevy Master Tech
Category: Chevy
Satisfied Customers: 1031
Experience:  ASE and Chevy Master , 31yr Dealership exp,
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96 Chevy s10 4.3 V6 with Enhanced Distributor Ignition. Turns

Customer Question

96 Chevy s10 4.3 V6 with Enhanced Distributor Ignition. Turns over but won't start. No spark on plugs or coil wire. ICM tested good at Autozone. ECM Batt and IGN fuses good. How can I pinpoint the problem?
Submitted: 6 years ago.
Category: Chevy
Expert:  Hal replied 6 years ago.

check the wire from the module to the ignition coil, the wires tend to break inside the insulation and or short out on the coil bracket.

 

If you need more info , or a diagram let me know

 

Thanks Hal

Customer: replied 6 years ago.
I don't get spark off the coil
Expert:  Hal replied 6 years ago.

The ignition module next to the coil. Has a power feed: Has a ground: has a signal from the Engine computer,: and sends a signal to the ignition coil. to fire the coil.

That wire is the one that if it is broken(open) or shorted to ground it will not trigger the coil to spark.

 

The diagram below shows the ignition circuit.

 

With a test lamp hooked to ground. : test for power( over 10 v) at terminal A ( pink wire) and D( white wire) of the ignition control module connector with the key in run position. Does it have power? Yes/ NO

 

Next turn ignition off: hook test lamp to battery positive post. Touch the end of test lamp to terminal C ( black wire) Does the test lamp light? Yes/ NO

Run these test and let me know the results.graphic

Customer: replied 6 years ago.

Pink wire yes, white wire no with key on....with key off lamp lights on black wire

Expert:  Hal replied 6 years ago.

The white wire is the one I mentioned above. it runs from the module to the coil, Check it close, they break the wire inside the insulation, and have a tendency to chafe/rub on the coil bracket. If in doubt , run a new wire from the D terminal of module to the C terminal of the coil.

 

 

Hal and 3 other Chevy Specialists are ready to help you
Customer: replied 6 years ago.
Maybe I misunderstood something. The light comes on when I probe the white wire on the coil connector (3 wires - pink white and white/black). The light does not come on when I probe the white wire on the ICM connector (4 wires - pink, white, white/black and black)
Expert:  Hal replied 6 years ago.

Look at the diagram. white/ black is terminal C of the coil This wire will have voltage on it. The Pink wire at terminal A of coil, feeds power through the coil and will come out of the coil on terminal C. This wire goes to the ignition module terminal D ( white/black)

So it should light( or have at least 10 volts) This wire triggers the coil to spark.

If you get no reading on the white / black wire at terminal D of ignition module. That indicates that wire is broken or shorted to ground. Thats why it wont spark. The coil is not being triggered.

To test to see if the module is sending the trigger signal. hook test lamp to the battery positive. touch the wire (connector hooked up) at the module.( use a safety pin to probe wire) . Have someone crank the engine. If it flashes the module is working. ( terminal D white/black)

The only thing stopping the coil from firing is the wire between the module and coil( white /black) shorted or open.

 

The white wire on the ICM connector is from the ecm. The white black wire is the one you want.

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