New alternator not charging

[Uniquestrain]

Hi everyone
I recently put a "new" m42 engine in my e30 and ive been having problems since then
When i wired everything up it started up but would die out after a few minutes, got so bad it wouldnt start.
I noticed my fuel pump wasnt turning on so i jumped the relay and now fuel pump turns on.
Guess that wasnt the problem cause it keeps turning off, i tested my alternator to see if it was charging and it wasnt so i went and bought a new one
Still nothing...im wondering if i connected something wrong or if my engine harness is bad

[romkasponka]

Is your engine ground cable connected?

[Uniquestrain]

Passenger side of the car is not the one next to the alternator
Can it be that ground? And if so where can i connect it to?

Is your engine ground cable connected?

[DesktopDave]

IIRC the stock E30 ground strap bolts between a stud on the passenger side inner frame member and the right motor mount arm.  I'd also be inclined to put a big fat wire off the alt mount bracket or bolt to the driver's side grounding block.