2008 Suburban 1500 LT 5.3L
Just finished a long block replacement. Leaving the coils & injectors unplugged and plugs out, I went to turn the motor over to prime the oil system. The first time I turned the key it tried to turn over but battery was too low. After charging I tried again but nothing happened. No click. Nothing. All the usual dash lights come on. Everything inside the cab works (windows, door locks, radio etc). The security light comes on and off in a couple seconds. The check engine light does not ever come on though. I got it to turn over and oil primed by jumping the start relay. It seems the ignition system will not energize with the key anymore.

Is there a problem with the ignition switch at the key? Or is this a BCM problem?

I need help!

 

It has a non-serviceable fuel filter on the fuel pump so it could be clogged or bad fuel pump. Need to check fuel pressure with gauge. Might be a timing issue too or an electrical problem. Are you getting any OBD II codes?

 

Fuel system has full pressure. No codes.

 

Are you getting any spark from the plugs?

 

No spark because the ignition circuit will not turn on.

 

I think you might have an issue with the camshaft sensor, or possibly the crankshaft sensor. Is the coil getting power? Could be the PCM or the ICM, but not likely.

 

think im confused. will the engine turn over with the key or will it not just run? are you getting 12v to the starter signal wire on the starter?

 

The engine will not turn over with the key. I have checked continuity of all fuses. All good. Fuses that should have 12v when the ignition is on have 0v. I can only make the started work be jumping the start relay. I can’t find any ignition switch wire diagrams for a 2008 anywhere. ???

 

have you tried starting in neutral?

 

Tried in neutral. No difference.