In your initial post you mentioned crankshaft position error codes.
Seems that could be a place to look at for a problem.

 

Swapped crankshaft position sensor. Didn't change anything.

 

Do you smell fuel in the cylinders when you remove the plug after trying to start? You may have a functioning fuel pump but is fuel reaching the cylinders?

I would also remove all of the air ducting and spray the starting fluid directly into the throttle body.

Just remember, if it is not firing, it is not combusting, and the more you continue to spray in there, the larger boom it will make when it does ignite. Yes it is in vapor form, yes it will dissipate with time, but done sequentially in a short amount of time, it can become problematic and in some cases shoot flames. So don't build a bomb out of your engine.

Highly suggest doing a loan a tool at AutoZone or similar for a compression tester. don't believe you have mentioned that it has attempted to fire. If the timing belt/chain/can't remember has broken or slipped you will certainly see it in the compression readings as the valves will be out of sync with the compression stroke itself. Target is probably around 190 200 with less than 10% variation across all 6 cylinders. The kit comes with adapters and what of them will match the threads for the plugs in the block.

If this has indeed happened, you may have already crushed valves or damaged Piston or both. The internal damage might explain the under load comment you mentioned in your last post as mechanical aspects of a freely properly timed rotating engine may no longer be intact

Please read up on the proper way to perform dry and wet compression tests, both cold and at operating temperature. Wide open throttle is a must while cranking. Otherwise you get unrepeatable incorrect data. All plugs removed while doing the tests as you do not want any head gasket issues and leakage between neighboring cylinders to influence each other.

 

Try removing all six plugs and having your wife crank the engine well you listen and observe sounds coming from the cylinders. You will get a brisk whoosh sound in the cylinders with good compression as they come up on the compression stroke. If you find this is not happening on all the cylinders, you likely have an internal problem. Consider this the poor man's qualitative compression test. It's not a substitute for the real thing but it will give you a clue if you have dead cylinders.

Have you done any investigation into the ignition system itself rather I should say the ignition module and what controls it? That would include what conditions inhibit it. Security tripped? Crankshaft position sensor bad? Food for thought.

 

Picked up a compression tester this evening on my way home. I'll read up on it and post what I find in the AM. I know I have good fuel flow at the fuel rail but I can't test at the injectors. I have definitely taken it easy on the starting fluid and it showed no sign of helping at all. Ignition relay and fuse are both good. Spark at each coil and plug. Swapped crankshaft pos sensor. I'm really hoping its not an internal problem but I'm feeling less confident each day. I'll repost when I have compression readings.

 

Removed all 6 plugs, disconnected all coil packs, removed fuel pump relay and did a dry compression on all 6 cylinders. None moved from zero. Decided to test compression on lawnmower just to make sure I performed it correctly. Had 30-40 psi there. So I guess I'm left to assume timing chains have popped? Any way of checking/knowing if there is any internal damage before taking the time to do a timing chain kit? Any tale tale signs that something else is really jacked up?

 

If you still have the tester, pull a plug on one of your other vehicles and ensure you get a valid reading in the 190- 210 ish range to be 100% sure that the tester is not the issue before you start tearing the engine apart. Given the amount of work involved, even better get a different tester if they have more than one laying around.

Sometimes the fittings work loose when you disconnect from cylinders before moving to the next cylinder. Or some yokel has trashed the tool and the seals are missing.

It's worth the time to be sure in this case.

Also, be 100% sure you have the right adapter on there and that it is fully threaded in there.
You had mentioned that at one time you saw some "stuff" blow out of one of the spark plug holes. Though it may no longer be the case, again, it's worth a second check.

0 compression across the board COULD be the result of 2 completely annihilated head gaskets, but that's not how they usually go and the chances are slim.

You haven't mentioned oil in the coolant or coolant in the oil -- "the milkshake" -- so I also doubt it's a head gasket issue.

Again, it's worth the double-check.

Was this vehicle ever run horribly low on oil?

 

How many miles on this engine? Sounds like a chain failure which probably bent all the valves. It will depend on where you live as to whether it is worth fixing your car. If you live in the rust belt and your car is showing signs of rust then it is probably time to move on. However if there is no rust issues then it is a completely different story. I live where cars do not suffer from rust so I am going to put a hot rod engine in my car and it has 245,000 miles on the chassis and will run for many more years.

 

I did attach compression tester to Tacoma and it had compression, so tester was good. The truck has around 130,000 miles on it and we live in SC so no rust issues here. I was thinking about doing the timing chain job while engine was still mounted in car. Watched several videos that shows its possible but I feel like if its a great possibly that the valves are bent then it would make more since to go ahead and pull it. What do y'all know about Cloyes kits. Is there a better option and has anyone done a timing job yet on there 3.6?

 

I think you have experienced what the early L61 2.2 Ecotec engine owners experienced. GM is notorious for letting the public do their testing on new designs. My engine came with a chain oiler that easily plugged and then timing chain failure quickly followed. It took GM 3 years to finally start using a much larger oil nozzle. The first 3 or 4 years of the 700r4 automatic transmission back in the 80s also had extreme failure rates. I now run one behind my 6.5L diesel in a one ton truck, this is after many updates and some aftermarket parts.
So I said all that to say this. If Cloyes is the OEM manufacturer which is logical because they are the OEM fo my L61 engine then yes buy the latest version of the parts for your engine. If you are set up to pull the engine and repair it on an engine stand then do this. The engine can certainly be repaired in chassis if you choose. There is probably no damage to the pistons or crank. There is most likely 20 or so bent valves. Of course you might have damage but since it drove home and failed to restart the damage was low speed. Low speed is better, things bend rather than break. I would probably just remove the front of the engine and the cylinder heads. I have repaired many L61s that have lost chains and bent all the valves. I have never had any piston damage.
Good luck with your repair. I assume that your engine has had regular oil change maintenance.