Will the oil / temp sensors on a 225 ???

I would like to use a temp and oil pressure gauge in place of the indicator lights on my 03 225 will I have to replace the sending units ?

I don't think you can simply replace the sending units because the ECM depends on the readings from the oil pressure and temperature sensors, and to the best of my knowledge that signaling is proprietary. I believe that your only option is to add on additional sensors to drive seperate gauges. I did that for engine temperature, using off-the-shelf components. Send me an e-mail at [email protected] and I will send you the documentation on how I did that.

As for oil pressure, I don't know of any easy way to add on another sensor without drilling into the block, which I do not recommend. There are two oil pressure sensors - high pressure and low pressure. You must remove the cylinder heads to get to them.