ScottieB

yeah, i know this is the v6 board... but yall have helped me so much with my v6, i need a little more help. lol.

im going from a 89' 2.8 mpfi to a 92' 5.7 tbi. i have the engine in, the whole wiring harness from the 5.7 hooked up, but for some reason im not getting fuel pump action unless i take the fuse out and manually put 12v to the fuel pump line.

anyone who can help me, i will be greatly appreciative... i have posted on the tbi board and the engine swap... they say "replace fuel pump"... well, its a wiring problem, not a pump problem. I am getting a lot of fuel, but its all being sent from 1 injector (since i have the one injector manually 12v)... both injectors work, and both wires work to the injectors... i have manually put +12v to both injectors, but neither work when i do that... so i dont know what is wrong.

can someone please help! lol. im like 10-15 minutes of labor short of making my car fly, i just need this minor thing fixed.

thanks!

-ScottieB

project89

iTrader: (1)

i do belive when u go key on that 12 volts is supplied to the injectors and the ecm switches the ground on off to pulse the injector,atleast this is how it works on my megaquirt system.how are u supplying 12v to the fuel pump are u manual jumping the connector in the relay?? if so the just the relay is bad.

simple test for this is to unplug the relay and hookup a test light to the relay trigger wire and turn the key on and see if the test light flashes if so then the relay is reciving the 12v from the triger wire. if not thats ur issue.

if it does flash check the power leade from ur battery to the relay if that checks out jump the power in to the fuelpump line, if the pump turns on u have a bad relay

ScottieB

the relay clicks (the one under the hood)... and i switched it with a v6 relay i had lying around and it did the same thing. i am manually wiring it from the internal lights, so i can just hold down the door hing button to stop power, or let off to give power to the injectors. its through the light switch on the fuse panel. at the bottom (no fuse in it)

TomP

Well here's a full diagnostic chart I typed up years ago. All you need is a test light; it will trace out every wire/relay/connection/etc.

Note that, of course, you didn't say you've got a code 54 flashing. Code 54 is "low voltage", and apparently, you've got zero voltage, so that's pretty low. (ha, ha) So the chart will still work for you, just ignore the code 54 bit.

https://www.thirdgen.org/forums/v6/60722-code-54-a.html

ScottieB

i'll try this tomorrow before work, or on my next 3 days off. thanks for the response