E30 Zone

Hi, i do abit of mechanics on the side and at the garage we have a mk1 e30 325 which the engine was no good so we put a 2.5 out of a mk2 in it.
Everything works fine but the rev counter doesnt work, Ive read on here it could be due to pin 9 on the c101 onnector but the engine we put in doesnt have a pin 9 and has quite a few less pins then the engine that came out.

Anyone got a way around this? Have tried everything along with lots of other clusters but none will wk.

The engine loom of your new engine should have a black wire at pin 9. This is the engine speed signal from the ECU, and needs to go to the rev counter. Never seen an engine loom that doesn't have this wire or pin!

Found out the problem with abit of research on this site. My car is a mk2 but the engine that has gone in is a mk1. The mk1 engine only has 12 pins on the c101 and an extra 3 pin plug. The mk2 has a 15 pin c101 which has the 3 pin plug included in it. So from what ive read all i need to do is wire the 3 pin plug to the back of the dash.