I have 2003 Oldsmobile Alero 3.4L and it wont start. When I crank the engine it has spark and fuel pressure test shows 50-55 psi. Placed light in injector #2 connector and no light as I crank. Gynesis scan tool showed U1016. Earlier scan showed P1626c which is security code. I did the key on 10 minutes step to reset the security light. Any ideas why still no pulse at injectors?

Question edited for clarity and typos.
Question moved to model category.

It is a known issue. Fuel pumps can work, but not provide enough pressure, so you need to test with a pressure gauge. There is also a Pressure Regulator. Have a read of this.

https://www.justanswer.com/oldsmobile/6cz1n-oldsmobile-alero-olds-alero-starts-dies.html

Lots more here

https://www.google.com/search?q=2003+Oldsmobile+Alero+starts+and+then+dies

You may need an auto electrician with a pro grade scan tool computer.

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Is the security light staying on ?
Usually the engine will not crank and you have no power to the fuel pump if the security system is disabling the car.
No injector pulse but spark would point to the computer since both use input from the crank and cam sensors.

Probably the fuel pump going out.

Hi there:
You will have to pinpoint what the engine is missing... Spark / Fuel / Compression

All three of these are tested when the engine is being cranked over. There are two way of checking for fuel. Fuel pressure and fuel trigger. Both are very important and must be present for the engine to start. Fuel pressure is self explanatory. You just hook up the gage and see what the reading is. Fuel trigger is check with a noid light. The injector gets unplugged and the noid light gets plugged in to the injector clip. With the engine cranking over, this light must blink. This is the signal to the injectors from the computer. You can have all the fuel pressure in the world, but it wont matter if the injector is not pulsing gas into the cylinder like it should.

Compression tester, spark tester, fuel pressure gage and noid light are all accessible at your local auto store. All three tests play a very important part in diagnosing a no start condition. Be extremely careful when doing these tests.

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fuel pump relay or fuse to the relay

Some check engine or anti-theft light there? We will have to pinpoint what the engine is missing...
- Spark
- Fuel
- Compression

All three of these are tested when the engine is being cranked over. There are two way of checking for fuel. Fuel pressure and fuel trigger. Both are very important and must be present for the car to start. Fuel pressure is self explanatory. You just hook up the gage and see what the reading is. Fuel trigger is check with a noid light. The injector gets unplugged and the noid light gets plugged in to the injector clip. With the engine cranking over, this light must blink. This is the signal to the injectors from the computer. You can have all the fuel pressure in the world, but it wont matter if the injector is not pulsing gas into the cylinder like it should! Compression tester, spark tester, fuel pressure gage and noid light are all accessible at your local auto store. All three tests play a very important part in diagnosing a no start condition.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

im pretty sure its your timing belt

start by checking for spark, then check fuel pressure and injector signal, so you need a spark tester and noid light

If the pressure is slow to rise, you should consider changing the fuel filter if it has not been done in the past 30,000 miles.
Next, disconnect a spark plug and check for spark while engine is cranking. Use a spark tester or old spark plug grounded to the engine block.
Let me know.
Regards,

Engine Cranks But Will Not Start

For an engine to run, you need three things to happen inside the engine. Compression, fuel and ignition, without any one of these components the engine will not run.
Basic Checks:

A. Test Fuses. Test both under hood power distribution center and the fuse panel under dash. This is done with a test light tool. The test light should illuminate on both sides of the fuse, if not the fuse has failed and needs to be replaced.
B. Testing Fuel Pressure Test for proper fuel pressure with a test gauge on the fuel rail, most throttle body injection cars (TBI) are between 13 psi and 17 psi. and most (DPI) direct port inject systems are between 40 psi and 55 psi. If no or little fuel pressure is observed and there is 12 volt power present the fuel pump, the fuel pump needs replacing.
C. Checking Timing Belt Test for compression by removing a spark plug and insert a compression gauge. Crank the engine over about 5 seconds the gauge should read between 125 psi and 165 psi, if no compression is observed remove front engine cover to inspect timing belt or chain. Crank engine to observe cam rotation, if the cam does not rotate the timing belt or chain has failed. (note: if the timing belt drives the water pump it is best to replace the water pump at this time)
D. Test for Injector Pulse Remove injector connector to insert injector test light (node) or volt meter. Observe light flash or gauge pulse while cranking. If light/voltmeter doesn't respond, an ignition distributor/crank angle sensor (CKS) or an ignition module is most likely your problem.
E. Test for Ignition Spark Remove spark plug wire, insert an extra spark plug into end of wire, rest spark plug next to a ground source then crank engine. You should observe a blue spark between the spark plug gap and ground source. If no spark is observed, an ignition coil, ignition rotor or spark plug wires might have failed. (always keep hands away from engine when cranking)