starting problems
 

i have a 91 740, i have replaced the fuel pump, fuel pump relay, fuel pressure sensor ,air temp sensor,map sensor, o2 sensor, distributor cap and rotor button. it has a regina ingition system. it will turn over but will not start. please advise what them problem could be..... I have all but given up

thats a lot of parts to replace without doing any diagnostics.

to start, you need compression, spark, and fuel. you need to figure out whats missing.

It could be your crank positioning sensor or your ignition control module, but do what Pierce says because if you don't you will keep replacing parts and throwing money out the window.

failed CPS == no spark *or* fuel

past that, I dunno, I have zero experience troubleshooting regina systems, I've never even seen one up close.

Also check your timing belt. Remove the oil cap and peek inside while a friend cranks the engine. If you don't see the cam moving then your timing belt is broke.