Uluz2a6

2006 2.2 Cobalt.

Just removed, rebuilt, and replaced engine. I am experiencing a crank but no start condition. Injectors are not spraying. I am comfortable with engine mechanical, but fall short on the electrical side.

I think it has an open ground because the crankshaft position sensor harness has 2.4 volts on both sides of the connector.

I have scoured the engine bay for a pinched or missed ground wire with out any smoking gun. I have tried to read the wiring diagrams, but cannot seem to find which ground(s) satisfy the ECM.

If I am reading the diagrams correctly, the crankshaft position sensor (CKP) is what signals the ECM to pulse the injectors. That's why I checked for resistance at connector after verifying it has continuity all the way to ECM. Finding voltage on both sides of connector screams missing ground... Right?

USMCFieldMP

iTrader: (1)

Are you sure that you have fuel pressure?

Does the tachometer move when you're cranking? Honestly, I've never paid attention and don't know if Cobalts do this, but I know it's the way to diagnose bad crank sensors on almost every other car that I've owned.

Uluz2a6

No reading from tachometer or on scanner while cranking. But that is not a surprise with voltage on both sides of sensor connector.

USMCFieldMP

iTrader: (1)

I'm not sure that it's a missing ground so much as maybe a misplaced ground or a shorted ground. A missing ground should tend to not allow the flow of electricity.

There are a couple grounds that connect to the starter/transmission area. A large ground connects the engine block to the body (behind/under the driver's side headlight) and there are a couple others scattered about.