Got an 07 charger 2.7 6cyl back in April. Since then have replaced the pcm, ac clutch, thermostat n housing. The end of August car overheated really bad on highway n wouldn't turn over. Have now replaced the head gaskets, harmonic balancer pulley, map sensor, egr valve, n gor a new battery but still won't turn over. Reading codes 403 n 406. It has backfired a few times so have checked timing n at one point someone said cylinder 6 wasn't getting spark. What do I need to look for next to help it turn over?

 

sounds like a nightmare. Sell it

 

get new coil packs or switch cylinder 5 pack with 6 and see if problem follows

 

I would definitely look into the timing, and if you have to go in there I'd replace the water pump since it is driven by the timing chain. I can't recall the details on how to check timing on that particular engine off the top of my head, but if you have a Haynes manual it'll tell you.

 

When you write "won't turn over" do you mean the starter doesn't engage or try to spin the engine, do you mean the starter spins the engine but it won't fire and run?

For the diagnostic codes, please provide the complete number. It makes a difference. If the codes you got were P0403 and P0406, those both relate the EGR system. You might have a nasty vacuum leak causing the engine to not want to start, assuming the engine is spinning just never starting and running.

Do you know how the "someone" determined cylinder number 6 is not getting spark? Were they maybe getting the P0406 code confused with a P0306?

-Rod