1990 Oldsmobile Cutlass Will not start

Hi Michael Fitzwater, Welcome to 2carpros and TY for the donation

Inspect and test the coolant temperature, throttle position and manifold absolute pressure sensors-also clean out the idle air control valve and EGR valve to include the testing of the fuel pump relay and fuel pump/oil pressure sending unit

What's up Fitz? Engine coolant temp tells the computer how much fuel and air to send. On startup, the engine needs all the fuel and air it can get. When the engine coolant temperature sensor realizes that the engine is warming up (i.E. The temperature of the coolant flowing across the sensor) the computer retards air and fuel mixture.

These models of Oldsmobiles as well as other GM cars with the same platforms had high failure rates of the ECM (engine control module) or engine computer. It would help to see if the OBD1 (first generation) will allow you to communicate with it.

How long can you keep it running before it dies?

I hope they'll test the PCM. Just because it's at the dealer dosen't mean they have the best techs. Believe it or not, one of the best ways to test one of those was to slap it, (ECM) and see if the car died.

Alphabet soup is what it is. ECM, PCM, they are the same in the regard they are both engine contollers. But, there as many as 12 different CMs (Control Module) on most cars built after 2001, that monitor just about everything else on the vehicle. Lots of fun sometimes!