Issues after engine replacement
 

Hey guys, hoping someoneay be able to help me out. I gotta give a little back story, it is pertinent to the rest of the info...

I bought an abandoned HHR with no keys and a bad engine. After I got the title, I decided to start messing with the car. I had no keys at first but wanted to see if the engine was seized or not. So, I took out relay 34 "crank" and jumped the terminals (30/87) and the engine cranked just fine but, obviously, didn't start.
I got a new steering column with keys from a junkyard, installed it and relearned the key. The engine started right up and ran but did have a lower end knock, I drove it a bit to see if there were any other issues and I didn't notice any, so I bought a replacement engine from a Junkyard. So, last night I got it installed.

I made sure get the car running and driving before touching anything just to be sure I would know if any problems after the swap were new or preexisting. The battery wad dead (had been sitting for months now) so I had to jump start it to drive it into the garage, so I did. I did the engine swap, pretty easy and straight forward, took me about 5-6 hours in all. Now, I put the car in neutral and disconnected the battery before I did any work on the car (needed to be able to push it forward/backward while it was in the garage.
After the swap was completed, I hooked up the battery (forgetting it was still in meutneu with the key on from earlier) and everything started flickering/flashing really fast. So I threw it in park, pulled the key out and disconnected the battery. I let the battery charge overnight and hooked it back up this morning. Now the car won't do anything. Headlights work, radio, power windows, wipers, etc... But when I turn the key, nothing. Not even a click. The fuel gauge isn't working now either.
Now it gets more concerning. Before, when I took the relay out and jumped the pins, the engine would turn over, now.it doesn't. I also jumped the fuel pump relay beforehand and it would run just fine, fuel pump won't run when I jump the terminals on that relay now either. Its also saying "low fuelf now when the tank is nearly full and it was showing that before the swap. On top of that, my scanner will no longer communicate with the OBD diagnostic port.


I have a good battery in it (borrowed the one from my '14 Camaro SS just to eliminate that as a concern), I went back and checked every harness connection and ground in the engine bay, they're all good. I checked EVERY fuse and relay in the car and under the hood, they're all good. I tried have the car in P and N, won't turn over either way. I even disconnected the shift linkage and manually put the switch into P/N, no change.
It got a new starter because I broke a terminal on the old one, I had them test it when I bought it, it's definitely good too. I'm leaning toward an ECM issue... I'm mostly confused by the fact that jumping the relays in the fuse box no longer works. I think that may me helpful in diagnosing the issue but I thought I'd come to the experts.

Since it has happened before; Did you hook the cables up right when you re installed the fuse box?

Did you check for voltage on the fuses or just continuity?

not sure what you mean by "since it happened before". Also not sure what you mean about the fuse box, I never unhooked it. Fuse wise, I just checked the continuity on em all

How did you get the engine in & out without moving the fuse box?

What I mean is "don't get offended" some other guy hooked the battery cable up to the power steering lug, It has happened before.

I suspect that there is no power going to the fuses, so continuity doesn't tell anything.

I took the intake, alternator and AC compressor off the engine, unbolted it from the trans, unbolted the front engine mount and pulled'er right out the top in about 2~ hours.

I checked and there is power going to the relays/fuses under the hood. However, if I jump the relay, it doesn't activate the fuel pump, or starter. If I jump the DRL relay, they turn on, jump the headlights, they turn on, etc...

So, whatever is between the relay box and the actual components (starter, fuel pump) must be the issue. I'm not sure exactly how that works. Do signals go through the ECM then to the fuse panel on those things or through the fuse/relay THEN into the ECM...? if the fuse box gets the signal first, then goes through the ECM, I'd say that has to be my issue really.

I'm gonna swap out ECM's here in the next day or two and see if that gets me anywhere.