Solved

[Nick's e30]

Solved.

[AndrewBird]

Sounds like there is a short somewhere causing a large drain on the system. Double check all your wiring on the air stuff.

[rcsoundn1]

^I would agree. Seems the air system has a serious draw. At least you know what system to start checking

[DaveSmed]

I'd be more inclined towards looking for a poor connection or inadequate cabling. If the connections were good, battery and charging system ok and system voltage was being pulled down to 1.5v, diagnosis would simply be "whats on fire?"

Post a couple pics of how your setup is wired.

[DaveSmed]

And these connections are made directly at the +ve terminal in the trunk, presumably with ring terminals around the terminal bolt?

[DaveSmed]

So your connection is at the highlighted point in the print below?

[DaveSmed]

In that case, my recommendation is twofold.

Obviously I would recommend moving over to a direct battery connection. Having a largeish inductive load in the power feed for the DME probably isn't the best path to a smooth running e30. Though not really that bad, its not exactly good either. You simply will see large voltage sags every time it kicks on. The electronics will probably manage ok, but the fuel pump will probably change quite a bit.


That said, it sounds like there may be a marginal connection to your fusible link. Thats the kind of thing that leaves you on the side of the road someday. Perhaps troubleshooting the connection with the compressor connected there as a test load, then moving it over to a direct connection would be your best bet?