While driving engine started losing power and then shut off and will not start

Hi,

What you described sounds like a bad crankshaft position sensor. Was it the tachometer that was jumping around? I ask because that would support my thoughts. At first, I thought fuel issues, but the needles jumping around is what changes that idea. Let me know if it was the tachometer.

Do me a favor. Take a look through this link. It discusses common symptoms of a bad crankshaft position sensor. See if it seems to mirror what you are experiencing.

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

If it doesn't and the vehicle doesn't start at all now, try this. Using starting fluid, see if it will start for a couple seconds before it stalls. If it does, then we can assume it is a fuel related issue, possible fuel pump. If it doesn't even try to start, then suspect ignition, specifically the crankshaft position sensor.

If you would rather, here are two links you may find helpful. One explains how to check for ignition spark and the other how to check fuel pressure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

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

Let me know what you find and I can further direct you.

Take care,
Joe

Hi,

Have you checked fuel pressure? I realize the pump is new. However, the idea that you are hearing a high pressure sound after it stalls could indicate a pressure issue. Likely, it's too high.

Is it possible for you to record it starting and the sound so I can hear it?

Let me know.
Joe

I hear you cycling the key. Are you continuing to try to start it and nothing is happening? (no starter engagement)?

If that isn't the case and pressure is good, it is likely ignition related. If I had the vehicle, I would check to see if spark is lost when it refuses to start. If it's lost, replace the crankshaft position sensor. You can use the test procedure I listed above. If you guys have a live data scanner, check to see if the RPM signal is lost when it won't start which would indicate the same thing.

With pressure where it should be, my first suspect is the crankshaft position sensor. Check to see if spark if lost when it won't start at all.

If you determine the sensor is the issue, here is a link that shows how in general one is replaced:

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

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Here are directions specific to your vehicle. The two attached pics correlate with the directions.

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2006 Chevy Truck TrailBlazer 4WD L6-4.2L VIN S
Crankshaft Position Sensor Replacement
Vehicle Powertrain Management Sensors and Switches - Powertrain Management Sensors and Switches - Computers and Control Systems Crankshaft Position Sensor Service and Repair Removal and Replacement Crankshaft Position Sensor Replacement
CRANKSHAFT POSITION SENSOR REPLACEMENT
CRANKSHAFT POSITION (CKP) SENSOR REPLACEMENT

REMOVAL PROCEDURE
1. Raise and support the vehicle. Refer to Vehicle Lifting.

pic 1

2. Disconnect the crankshaft position (CKP) sensor harness connector.
3. Remove the CKP sensor retaining bolt.
4. Remove the CKP sensor from the engine block.

INSTALLATION PROCEDURE

IMPORTANT: Inspect the sensor O-ring for the following conditions:
- Any wear
- Any cracks
- Any leakage

Replace the O-ring if necessary. Lubricate the new 0-ring with engine oil before installation.

pic 2

1. Install the CKP sensor into the engine block.

NOTE: Refer to Fastener Notice in Service Precautions.

Tighten the bolt to 10 N.m (89 lb in).

2. Install the CKP sensor retaining bolt.
3. Connect the CKP sensor harness connector.
4. Lower the vehicle.
5. Perform the CKP System Variation Learn Procedure.

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Let me know what you find.

Joe

Try this for me. Connect the scan tool and when the engine will not start, see if there is an RPM signal.

Let me know.
Joe