Engine cranks but does not start

1995 BUICK LESABRE
137,000 MILES • 3.8L • V6 • 2WD • AUTOMATIC
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CHARLES STEELE
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  • 37 POSTS
Started fine turned off put some gas in and now wont start. turns over but no spark. i cannot run a scan my scan tool will not work on this car it is not compatible obd11 plug but not obd11 system right at that time when they were changing to the new system.
Mar 14, 2021 at 7:46 AM
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ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
Good afternoon,

Yes, during the changeover, they had an OBD2 plug that would not connect with the system. You needed a special adapter.

This sounds like it could be a crank sensor not sending a signal to the ECM.

https://www.2carpros.com/articles/car-cranks-but-wont-start

https://www.2carpros.com/articles/how-to-test-an-ignition-system

I attached the procedure below and a picture of the sensor.

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

Roy

EMOVE OR DISCONNECT
1. Negative battery cable.
2. Serpentine belts from crankshaft pulley.
3. Raise vehicle.
4. Right front tire and wheel assembly.
5. Right inner fender access cover.
6. Using 28 mm socket, remove crankshaft harmonic balancer retaining bolt.
7. Crankshaft harmonic balancer using special tool (J 38197).
8. Crankshaft position sensor shield.
9. Sensor electrical connector.
10. Sensor from block face.

INSTALL OR CONNECT
1. Crankshaft position sensor to block.
2. Bolts to hold sensor to block face.

^ Tighten to 20-40 Nm (14-28 lb. ft).

3. Crankshaft position sensor shield.
4. Electrical Connector.
5. Balancer on crankshaft.
6. Apply thread sealer to threads of crankshaft balancer bolt.

^ Tighten bolt to 150 Nm + 76° (110 lb ft + 76°).

7. Inner fender shield.
8. Tire and wheel assembly.

^ Tighten lug nuts to 140 Nm (104 lb. ft).

9. Lower vehicle.
10. Serpentine belt.
11. Negative battery cable.
Mar 14, 2021 at 8:10 AM
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CHARLES STEELE
  • MEMBER
  • 37 POSTS
any thing to check before replacing? i know it is not getting spark on at least one plug have not tested all.
Mar 14, 2021 at 3:13 PM
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ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
You would need a scan tool that will communicate with the system to see if you have a crank signal to the ECM.

I attached the diagram of the sensor as well as the location and a picture for you.

https://www.2carpros.com/articles/how-to-check-wiring

Roy

REMOVE OR DISCONNECT
1. Negative battery cable.
2. Serpentine belts from crankshaft pulley.
3. Raise vehicle.
4. Right front tire and wheel assembly.
5. Right inner fender access cover.
6. Using 28 mm socket, remove crankshaft harmonic balancer retaining bolt.
7. Crankshaft harmonic balancer using special tool (J 38197).
8. Crankshaft position sensor shield.
9. Sensor electrical connector.
10. Sensor from block face.

INSTALL OR CONNECT
1. Crankshaft position sensor to block.
2. Bolts to hold sensor to block face.

^ Tighten to 20-40 Nm (14-28 lb. ft).

3. Crankshaft position sensor shield.
4. Electrical Connector.
5. Balancer on crankshaft.
6. Apply thread sealer to threads of crankshaft balancer bolt.

^ Tighten bolt to 150 Nm + 76° (110 lb ft + 76°).

7. Inner fender shield.
8. Tire and wheel assembly.

^ Tighten lug nuts to 140 Nm (104 lb. ft).

9. Lower vehicle.
10. Serpentine belt.
11. Negative battery cable.
Mar 14, 2021 at 7:50 PM
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CHARLES STEELE
  • MEMBER
  • 37 POSTS
could a low battery voltage cause this? after all night on 2 amp charge to battery it started just fine this morning. i know the battery is not holding a charge but seemed to turn over fine but now it starts.
Mar 15, 2021 at 4:25 AM
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ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
No, not at all.

Roy
Mar 15, 2021 at 5:43 AM
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CHARLES STEELE
  • MEMBER
  • 37 POSTS
do the sensors work intermittently? Because it started and runs fine now.
Mar 15, 2021 at 8:53 AM
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ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
Yes, it can. You need to have it tested when it does not start to confirm the failure.

Roy
Mar 15, 2021 at 8:57 AM
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CHARLES STEELE
  • MEMBER
  • 37 POSTS
i will have to see if i can buy a tester. it is a 3 hour drive each way from were i live to the nearest town that has more then a bar and gas station. i am in the north east corner of Nevada old ghost town.
Mar 15, 2021 at 9:02 AM
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ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
Okay, keep us updated.

Roy
Mar 15, 2021 at 9:06 AM
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CHARLES STEELE
  • MEMBER
  • 37 POSTS
thanks.
Mar 15, 2021 at 9:20 AM
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ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
Anytime.
Mar 15, 2021 at 9:21 AM
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