Hey everyone, I just have a question about the PCM connections on the engine.

Now I have dropped 2 engines so far from bottom, a LS1 and LT1. It's pretty easy straight forward to do. Both times I took the PCM out with the engine (just layed on top and dropped) I just unhooked it from the inside. And basically unplugged every sensor.

My question is, if you decide to drop the harness with the engine. Is it necessary to unplug all the sensors that are on on the engine? Like the injectors, stuff on the manifold, some sensors down below.

Or can you just leave those connected and only disconnect the PCM from the inside, the big plugs on top of the passenger fender (I think they're called c100 or whatever) and the grounds, and stuff that is connected to the body of the car.

If not, it's no biggie I plan to mark everything on my car anyway. And I did TW other 2 cars disconnecting all the sensors on the engine. But it makes sense since I'm dropping the PCM that they are just gonna drop down with it anyway connected or unconnected.

Thanks for your responses, I'll be dropping my engine LT1 soon for ported heads with bigger valves also a ported intake manifold and a CC503 cam. Doing all seals and gaskets and painting a bunch of stuff and cleaning.

And maybe if I feel like it I might make a video on all the steps on how to drop the engine.

 

you dont need to unplug any sensors on the engine if you take the harness

 

The whole point of leaving the PCM/harness with the engine while dropping it out is that you don't have to disconnect anything on the engine, itself.

 

Sweet ok, that's what I was thinking. Just wanted to make sure.