1990 cutlass ciera w/3300 v6, won't start, fuel presure is 45psi, has good spark, has new crank sensor. still won't start, what next.

Check for spark when it won't start. If you have spark, might be your fuel pump relay, maybe the map sensor. If no spark, check another or all plug wires. If ignition isn't working, it could be Crankshaft Position sensor, Camshaft position sensor (or pick-up coil), ignition control module, coils, pcm, or the wiring associated with them. PCM determines spark timing after inputs from crank and can sensors, and sends ground signal to ignition module, cutting primary voltage to coils, initiating spark or high voltage from coil to sparkplug. All these parts have to be working right for ignition. All can be tested too. You'd need a digital volt ohm meter (DVOM) and a repair manual for your car with the test procedures. That Mitchell alldata-diy site has a special on subscriptions, pretty reasonable for a 1 month subscription, and excellent info and troubleshooting flow charts, wiring diagrams, etc.

Check all vacuum lines, if ok then do a smoke test, sounds like there is a vacuum leak. hope that helps.

You need to figure out what you are missing. What is the fuel pressure at the rail when you are cranking the engine? It needs to be above 40PSI. If you have sufficient fuel pressure you need to check for spark at the plugs while cranking. If you verify you have sufficient fuel and spark then you need to look to timing and compression. These are the four things an engine need to run. Fuel, spark, compression, and timing.

the most common problem next is the crank sensor. use a heat light to warm up the sensor to see if it is that. by using a heat light you can narrow down what part has the temperature glitch. Don't forget to try the engine computer.

Most of the time when it starts for 1-5 seconds then dies, its a failing of the antitheft system. Read about it thru this link. Some possible solutions too. http://vatspasslockpasskeysecurityhelp.yolasite.com/

The pressure will revive itself. Just start it and check for leaks.

replace the crankshaft position sensor, it will cure the problem.

most common cause of no spark is the ignition module located under the coil

CRANKSHAFT POSITION SENSOR

Fig. 8 Ignition Coil Module Assy 2.5L/4-151 The Crankshaft Position Sensor is mounted remotely on the bottom side of the ignition module.

RH Side Of Engine.

Front RH Side Of Engine

Applicable to: Cutlass Ciera & Cutlass Cruiser w/V6-231/3.3L

Try testing the crank sensor.