My son's '94 Saturn began will not start.

So the spark he gets is a orange/yellow?Also is there battery voltage going to the ignition module?So what is the actual fuel pressure?Have you checked for injector pluse?Also have you checked for codes?Its cranking over normal speed when trying to start it?

It is not throwing a code. A spark tester used at a plug wire boot gives him a 'weak' spark readind intermittently while the care is cranking, and it is cranking at normal speed while cranking.

Have not checked the actual fuel pressure or for injector pulse. I told him to unplug the injector and then crank it and see what that does to the reading the spark tester gives him.

Spark is bright blue.

Bright blue spark is not a weak spark yellow would be.Unpluging the injector shouldnt effect spark.You need to check actual fuel pressure and see if you have injector pluse.So is it sparking good on all the cylinders when checked with a spark plug?Also another i would check is if the spark is good is the coolant temp sensor that can cause a no start.It would be the bottom sensor with two wires going to it a black one and a yellow one.Also inspect the connector too it the inside of it if the terminals are blue or green instead of silver then you have to replace the connector.

I'm headed to his apartment today and we'll check all the things you've listed when I get there.

The one thing that threw me was the fouled and burnt plugs he found when the car originally started giving him trouble. This thing was a basket case when we bought three years ago and everything that he's checked and you've suggested checking was replace at that time, even the coolant temp. sendor.

The coolant temp sensors have a high failure rate i have had my 1999 saurn SL2 for 6yrs now and iam on my fourth coolant temp sensor.Let me know what you find also make sure you check the bottom coolant temp sensor with two wires going to.it and thr cannector.let me know what you find.