E30 Zone

converting my car from motronc 1 to 1.3 just had it running but,
is the smallest of the three starter wires (black/green) meant to go to the solenoid earth?
if i put a chip from a 173 ecu in a 172 will it be ok for a 2.5?

Black/green goes to a dedicated terminal on a facelift starter motor. If you are using a pre facelift motor, change the ring terminal for a 8mm one and fit it to the inner large stud on the solenoid - the one that has a link or braid going into the motor body.
A 172 ECU with a 325 chip becomes a 173.

great thats what i thought thanks again.
another problem i've got is the abs light is on due to the conversion and i can't find what wire i'm meant to splice from the dme relay to where?

Conversion shouldn't have affected an existing ABS system. An E30 with M1.0 should have the ABS switched power controlled by a silver relay above the glove box catch, completely independent of, and unaffected by, an engine or loom change.
The silver relay doubles up as a voltage spike quenching device, but unfortunately, it's a one shot device.
Any chance you could have caused a voltage spike while firing up the engine with the new loom?

unfortunately yes. i'll have to try the externel fuse mod.