Fuel Injector not working

Did you test for spark? I would check spark and fuel pressure. OK, here's a little bit of working theory that'll help you to see the ‘why’ of the Noid light test.

Whether you're testing a No Start Condition or a Misfire Condition, you'll need to know if the cause of the problem is a lack of fuel. When your GM 3.8L (Buick, Chevrolet, Oldsmobile, Pontiac) does not start, it will be either because of a lack of fuel or spark. The same thing goes for when your GM 3.8L equipped car or mini-van is misfiring... that specific engine cylinder isn't contributing to engine power because it either lacks fuel or spark.

Now, since the above two conditions (No Start and Misfire) can be caused by any number of things... one of the things that has to be eliminated, from this list of possibles, is the fuel injector not getting power or the injector pulse signal (On/Off switching signal) from the vehicle's Computer.

This is where the fuel injector Noid light test comes in handy, because you're able to visually see if both of these signals are present or not. If no flashes, then now you know that you have to verify that the connector is getting power (12 Volts) and the injector pulse signal.

One thing to keep in mind, is that the fuel injector Noid light test does not test for a BAD fuel injector. But, is the first step in verifying if the fuel injector is BAD or not. For the fuel injector test tutorial.

With a noid light .
9pc Electronic Fuel Injection Signal Noid Lite Tester Light set GM Ford... or you could use just a test light . Video's on youtube showing how.

What test told you it is not firing?

You may have valve damage &
little compression

use a digital volt meter,put it on the ohm scale check number 2 fuel injector should be 11 to 16 ohms if not reads zero fuel injector faulty.if numbe 2 fuel injector okay.use noid light hook it to fuel injector electrical connector with fuel injector disconnected and see if pcm is firing the fuel injector noid light should blink when cranking the engine.if light steady pcm not firing 2 fuel injector,if noid light dont light up.there is a open in the wiring connector 2 fuel injector 2. if fuel injector okay,check spark plug, carbon foul you have a bad ignition coil or wire if you see oil on spark plug you have worn piston ring or leaking valve guides allowing oil to foul out spark plug.do a compression test check compression to see condition of the cylinder.

Hi James, I'm glad to help!

James, there are many things that can cause a misfire from severe vacuum leaks too mechanical problems. The first step is to do a "Compression Test" to see if your miss is related to valve or ring issues. If you do have low compression then your need to do a "Cylinder Leak Down Test" To determine where the lose is coming from. If there are NO problems found with compression then your next step would be to check "FUEL PRESSURE" because the lack of proper fuel pressure can also cause misfires. If fuel pressure is not the issue then your next step would be to check to make sure your injectors are getting the correct power and ground by using a noid light to test each one. If you find that there are NO issues with the injector circuit, then your next step would be to remove the injector rail, turn the key on while watching the injector spray patterns to see if its spraying evenly and there are no drips after the injector turns off. Because large amounts of fuel dripping from the injector will also cause misfires. This should be enough to help you in the right direction of finding the problem. Hope this helps and have an awesome day James.

Hi there:Sound like a starter problem, also check battery charge. Spark, fuel and 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.

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.

FUEL INJECTOR NOT FIRING COULD BE FAULTY FUEL INJECTOR.HOOK A NOID TEST LIGHT TO FUEL INJECTOR ELECTRICAL CONNECTOR. CRANK THE ENGINE WATCH THE NOID TEST LIGHT SHOULD BE BLINKING WHILE ENGINE TURN OVER.IF TEST NOID LIGHT STEADY PCM FAULTY NOT FIRING THE FUEL INJECTOR.IF FUEL INJECTOR DONT BLINK OR LIGHT UP.YOU HAVE OPEN WIRING CIRCUIT TO THE FUEL INJECTOR CONNECTOR.

CODE PO205 - IS INJECTOR 5. YOU NEED TO USE FUEL INJECTOR NOID TEST LIGHT OR A STETHOSCOPE TO CHECK ALL FUEL INJECTORS TO SEE OR HEAR WHAT FUEL INJECTOR NOT WORKING.USE TEST LIGHT IF BLINKS FUEL INJECTOR GETTING POWER.THE STETHOSCOPE USE IT LIKE A DOCTOR TO HEAR WHAT FUEL INJECTORS WORKING.YOU SHOULD HEAR CLICKING NOISE IF YOU HEAR NO INJECTOR NOISE AND IT IS GETTING POWER.THE FUEL INJECTOR IS FAULTY.

P0174 System Too Lean Bank 2
P0171 System Too Lean Bank 1

Have you tried to work on the fuel system side? Have you tried
fuel injector cleaner from a bottle into the gas tank?

i.e., fuel filter, fuel pump, fuel pressure readings from the rail,
fuel injectors:
Fuel Injectors Testing The easiest way to test the operation of the fuel injectors is to listen for a clicking sound coming from the injectors while the engine is running. This is accomplished using a mechanic’s stethoscope, or a long screwdriver. Place the end of the stethoscope or the screwdriver (tip end, not handle) onto the body of the injector. Place the ear pieces of the stethoscope in your ears, or if using a screwdriver, place your ear on top of the handle. An audible clicking noise should be heard; this is the solenoid operating. If the injector makes this noise, the injector driver circuit and computer are operating as designed. Continue testing all the injectors this way.
CAUTION
Be extremely careful while working on an operating engine, make sure you have no dangling jewelry, extremely loose clothes, power tool cords or other items that might get caught in a moving part of the engine.
All Injectors Clicking If all the injectors are clicking, but you have determined that the fuel system is the cause of your driveability problem, continue diagnostics. Make sure that you have checked fuel pump pressure as outlined. An easy way to determine a weak or unproductive cylinder is a cylinder drop test. This is accomplished by removing one spark plug wire at a time, and seeing which cylinder causes the least difference in the idle. The one that causes the least change is the weak cylinder.
If the injectors were all clicking and the ignition system is functioning properly, remove the injector of the suspect cylinder and bench test it. This is accomplished by checking for a spray pattern from the injector itself. Install a fuel supply line to the injector (or rail if the injector is left attached to the rail) and momentarily apply 12 volts DC and a ground to the injector itself; a visible fuel spray should appear. If no spray is achieved, replace the injector and check the running condition of the engine.
One or More Injectors are not Clicking Unplug the fuel injector connector
Probe the two terminals of a fuel injector to check its resistance
Plug the correct "noid" light directly into the injector harness connector
If the correct "noid" light flashes while the engine is running, the injector driver circuit inside the PCM is working
If one or more injectors are found to be not operating, testing the injector driver circuit and computer can be accomplished using a "noid" light. First, with the engine not running and the ignition key in the OFF position, remove the connector from the injector you plan to test, then plug the "noid" light tool into the injector connector. Start the engine and the "noid" light should flash, signaling that the injector driver circuit is working. If the "noid" light flashes, but the injector does not click when plugged in, test the injector’s resistance.
If the "noid" light does not flash, the injector driver circuit is faulty. Disconnect the negative battery cable. Unplug the "noid" light from the injector connector and also unplug the PCM. Check the harness between the appropriate pins on the harness side of the PCM connector and the injector connector. Resistance should be less than 5.0 ohms; if not, repair the circuit. If resistance is within specifications, the injector driver inside the PCM is faulty and replacement of the PCM will be necessary.

I assume this 'complete' tune up was plugs, wires and plennum (intake surge tank) gasket?
If so, recommend you first check to see if you are getting an injector pulse to the #3 injector (a noid light is normally used to verify the injector is receiving the 'pulse' from the ECM. The noid light is a very useful tool in finding out if you have problems with your fuel injector. It is cheap (around 10 dollars per piece), easy to use (if the light blinks, your injector is receiving the electrical pulse to open). If after you verify the injector pulse is present, the next step is to determine if the injector or cylinder is the problem. A simple verification process requires swapping the #3 injector with another to see if the misfire moves to the swapped cylinder.(.i.e, move #3 injector to #2 cylinder & the #2 injector to #3 cylinder.).. Then run engine to see if the P0303 changes to P0302. This would VERIFY the injector is in some way defective. If the misfire STAYS at #3 cylinder, you'll want to perform a compression test of all the cylinders. If after this test you find #3 cylinder is more than 10% lower than all the other cylinders, do a 'Leak-Down' test to determine if the low compression is due to leaky valves (intake or exhaust) or whether the piston/rings are the problem. NOTE: If all the cylinders are withing 10% of each other during the compression test, the possible causes are, injector O-ring leak, vacuum leak at the intake manifold at #3 cylinder, or the spark plug not firing under compression.