E30 Zone

i recently changed my 2.0l engine to a 2.5l the problem i am now getting is an intermitent one but what happens is when i rev the engine above 2000rpm the rev counter dies and the inspection light flashes quite rapidly, when it happened before i checked the oil and that was low so i topped it up and the problem stopped for a few days, it happens now at least every other day i checked the oil and that is fine, please can someone help me as i dont know what to do next.

thanks

What light do you mean by "inspection light"? I can think of three that could be described as this.

above the green service inspection lights there is the word INSPECTION thats the one that keeps flashing.

I now have the same problem,
I reset my dads service lights on his 325i e30
and now the Inspection light won't stop flashing and the rev counter won't work............... Help !!!

The inspection light should come on when the SI board tells it to, and stay on untill it is manually reset.
I've come across numerous different faults caused by a duff SI board,or more likely it's batteries, but this is a new one on me.
Must be the SI board though. Take out the instrument cluster, remove the SI board, and measure the voltage on it's batteries.
I and others have posted many times on how to change these batteries, so do a forum search.
Also search for "220 ohm resistor" while you've got the cluster apart, and check the nuts holding the fuel and temp gauges as well.