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What causes a 2010 Buick Lacrosse not to start if the starter is good and the battery is new but there is no clicking of the starter when the key is turned in the ignition? The grounds are tight and connected to the starter and the battery.

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  • Welcome to Motor Vehicle Maintenance & Repair! Do the dash and interior lights come on? Do the headlights come on like you'd expect? If no to these, you probably don't have your connections in good shape. I'd go back and take a look again. If the lights do come on, there might be an issue with the ignition switch or any of another hundred things. Commented Sep 29, 2018 at 0:32
  • All of the lights and electronic components come on..radio, dashboard..etc. I checked for blown fuses under the hood but there is a trunk fuse compartment. Commented Sep 29, 2018 at 1:19
  • Did you recently replace anything?
    – N8sBug
    Commented Sep 29, 2018 at 13:16
  • How was the starter tested? Is it new? Does it have ground? Is the s-terminal receiving voltage? Is the battery voltage on the b+ terminal?
    – Ben
    Commented Sep 30, 2018 at 0:42

1 Answer 1

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what causes a car not to start

To be brutally honest, a lot !

Start with turning the ignition to the on position, do you hear a hum, that means the fuel pump is good and priming, if no hum is present you need to check the fuel pump relay

Second, grab a fuel pump tester and connect it to the shader valve on the fuel injector line by the manifold, is their pressure, yes. 55psi and stable. good, now you can pinch the fuel line before the fuel pressure regulator, does fuel build up, good. The regulator is doing its job.

Third, Does the battery read 12.7 to 10.7 volts after a hour, good, Does the battery read 9.6 - 12.7 for 3 seconds while starting the car, great.

Fourth, Does the starter read 12v power to ground, good, Does the starter to solenoid still read 12v while cranking, great.

Fifth, Do you have ohms on your plug wires, any abrasions, blisters, burn marks indicating a bad wire

Sixth, is the coil pack good, any black marks, do the ohms match up. Use a 6 cyc coil pack for example, every 2, adding up to 6 should have the same ohms of resistance, I can't tell you the exact ohms because every car is different

Seventh, Crankshaft sensor, does it have ohms. Good

Eighth, PCV value, is it clogged ?

Ninth, MAF sensor do you have at least 0.1 ohms, not O.L, are you getting a voltage

Tenth, A bad coolant temperature sensor can prevent a car from starting, the ohms would rise as the temperature rises, should be around 1500 to 2000 cold

Eleventh, Alternator. If the alternator is bad it won't start the car because it can't keep the battery charged, the battery only starts up the car, the alternator keep it active.

Twelveth, spark plugs capped correctly ?

That's all I got, hope you can find your issue easier than checking everything inside of your engine :)

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    Overall, you list a lot of valid reasons why an engine might not start, but most seem to NOT address the OP's issue. Apparently his engine does not CRANK. This rules out anything like fuel, crankshaft sensor, PCV, coils, etc.
    – mike65535
    Commented Sep 29, 2018 at 10:06
  • Ignition control module or fuse ;)
    – user38183
    Commented Sep 29, 2018 at 10:07
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    Fuse, maybe. IIRC a 2010 is COP. Why would a ignition control module (which on gms is integrated into each coil) on a car that doesn’t crank be the problem? Even on the older 3.x engines why would a bad ICM cause a no crank?
    – Ben
    Commented Sep 30, 2018 at 0:39
  • Same reason a car won't even click if a coolant temp sensor is defective :)
    – user38183
    Commented Sep 30, 2018 at 0:56

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