IR XP750 air compressor.

Not sure if this is the right forum but here goes anyhow.

I am helping out a friend in the sandblasting business with a problem on his IngersolRand XP750 compressor. It's a 1996 model with a cummins 8.3 engine. I am in need of basic info on the unit. We have two problems.

1) unit wiring. Only have the operators manual and wiring diagram does not match unit.

Problem with building operating air pressure with service air button.

2) Oil carryover out discharge after running a minute or so at operating volume.

Any help will be appreciated.

Thanks

IR XP750 air compressor.