86 z28 died on the way home the other day. all stock. cranks likes normal fuel pump is not working or is not getting power checked all fuses. did diagnostic got code 12. cant seem to figure it out. replaced alternator 2 weeks ago.


86 z28 v8 305 5.0L TPI

 

If you used the paper clip code checking method, than you will always get a code 12 if in fact there are no codes. Code 12 alone, means that the ECM is functioning properly. I would check the fuel pump relay if you're postive that the fuel pump isn't working because thats one of the most common things that go up.

 

i replace the fuel pump relay and still no fuel pump. i can normally hear the pump turn on(buzzing sound). i have check all connections and replace fuel filter. still nothing. i heard something about the oil pressure switch turning off the fuel pump but cant locate it. i have also notice that the crank fuse (3a) is burning out every time i start the car but never noticed it before, its linked to the cold start injector. im still lost

 

Use your voltmeter or test light to verify you're getting voltage to the pump. There is a 3-pole Weatherpak connection near the gas tank, open this and probe the power pin while someone turns the key on. You should get ~12 volts for 2sec when the key is turned to the RUN position (not cranking) while the ECM primes the rails.

If you get voltage, but no pump running, you'll be replacing your pump. If no voltage but the relay is good, you have a wiring problem.

 

do fuel pumps just fail like that? i herd that they give you a loss of power before they fail. i tested the voltage to the fuel pump and it said nothing but that may be because we had the car on before we tested it. i'll try it again.... does anyone know about my crank fuse(3a) problem????

 

i remember back when i was a senior in H.S. i was leavign school and went of a speed bump at ehh.. idleing speed.. what ever that is. well when the rear tires came down, the car just stopped. come to find out my fuel pump for some reason just dies. so u might want to look there.. to back 86z had the pump inthe damn tank.. talk about a bitch to change