fbodygirl

Hello all, I have a question...I need to test the injector wiring plugs for pulse on my Firebird V6 2.8 engine. Car won't start. I have a noid light to do this, my question is how do I take the wires off the injectors Without taking the Plemun off? Is it possible? If Not, is it safe to crank the car over with the top of the engine apart? I wouldn't thinks so, So How Do I Do This? And I know I have to test both sides, but do I have to test All 6 of them? Any help would be great. Thanks!

project89

iTrader: (1)

u have to take the plenum off, just pull the power wire from the coil and it will be safe to crank the car over with the plenum off

Maverick H1L

iTrader: (8)

You don't need a noid light to test the fuel injector signal, and you don't need to take apart the plenum. Disconnect the front fuel injector harness connector and probe the 2 pink wires with a test light with the ignition turned on to check for power. Connect the clip of the test light to either the alternator BAT terminal or another source of +12V power, and then connect the probe to either the green or blue wire in the 4-wire injector harness connector and crank the engine. If the test light blinks (ECM provides ground for the test light through the harness), the injectors are getting a ground pulse.

More than likely, you probably need an ignition module inside the distributor. They go out all of the time. The only problem with testing for a fuel injector pulse is that a bad ignition module won't send an RPM signal to the ECM so you may assume that the ECM or one of the grounds is bad because the fuel injectors won't pulse if the ECM doesn't see an RPM signal. Take the module out of the distributor and have it tested.

fbodygirl

Thanks so much Mav for that info, but I did go out and buy a fuel pressure gauge yesterday. I connected it and the needle on the gauge barely moves. I really thought the pump was fine, because I can hear the relay and I thought the pump run when I turn on the key. I was going to move on to the fuel injector pulse after I made sure the pump worked, because I was for sure the pump was fine. So Is there any other tests to do before I pay to have the pump replaced or is it for sure dead? thanks again

Maverick H1L

iTrader: (8)

Take out the gas cap and have someone turn the key on. Sometimes the pumps are hard to hear, and listening through the filler neck is best. If the pump doesn't run, swap the relay (with the thick orange and red wires) with one of the ones next to it and test again. Also, if the fuel filter hasn't been replaced in a while, replace it. Check for fuel leaks under the car. Do you have any reason to suspect that the gas gauge may be off? If so, put a couple gallons in the tank from a can and try again (you could just be out of gas).

project89

iTrader: (1)

mav i thought the test light was bad idea cause it could fry the injector driver in the ecm due to over loading the circut ?

Maverick H1L

iTrader: (8)

I'd have to check the resistance of an average test light, but I wouldn't think it's too much less than the resistance of all 3 injectors on each bank of the engine (4 ohms for V6, 3 for V8).