90 240sx alternator ground problem

[180wanabe]

Hey so i have a complicated problem that makes no sense to me that i need help with. basically my engine is instead oif being grounded to the negative terminal it is shorted out to the + terminal. i found this out initially when i had the engine lower harness wired up and i tried to connect the driveshaft and it sparked from the grounding out to the differential. alkso my motor is in the process of being put back togethor. there are no grounding straps on my motor to the chasis and my battery is relocated to the trunk BUT the battery worked fine until i tried to connect the driveshaft. i have gone through tweo different lower hanress's and two different fuse box harness's and they still show the same problem. basically when the alternator two pin plug si connected the engine is shorted and when its disconnected theres no problems. But if i remove the alternator from the engine itwith it fully pluged in theres no problems as long as the groundd is disconnected i guess. BUT i tested the alternator and it passed all the tests so i have NO clue what the problem is and this is pretty much the only thing i need to figure out in order to get my car running. It also has a 91 ka24de in it. all harness's and stuff came off of running cars so it should work fine its just this little problem holding me back. any helkp would be appreciated.

[180fan]

The power line from the battery runs to the starter and the other two little wires run to the battery as well. Make sure those are all getting juice. Other thing to check is make sure there is that plastic ring thing on the back of the alternator. Without that, your power will ground out.

[180wanabe]

yeah there is the plastic thing i checked out the alternator and i ran an ohm test thorough the thing and its getting like 4.16ohms or something like that (fairly high for good power transfer) between the ground and the power plug. its also getting around the same between the two plugs on the connector and the body of the alternator if that helps anything but it did test out good so im assuming that this is normal?

[180fan]

how do you have your alternator hooked up?

[180wanabe]

just normally with the main terminal on the main post the smaller one grounded on the alternator then the connector plugged in its showing 4.62 ohms and im not sure if thats normal or what.