[AftermathAlero]

Did you ground the engine to the chassis in the front? If not.. then the engine is drawing powering from backfeeding in grounds in the electrical system. Add some grounds btw the engine block to the chassis. It will solve your problem.

Your ground in the trunk is fine.. the one from battery negative to the trunk. (make sure your surface is clean. i.e. grind or sand the paint off in that spot where the ground is going to be on.