zburnett

After porting the plenum, removing the runners, and removing the fuel rail the car wont stay running. I primed the fuel pump and checked the shrader valve on the fuel rail and no fuel came out. Also checked all injectors and all checked out ok.... So fuel pump!? also the carbon canistor pops while running. My guess is its running off of fuel vapors? Thanks for the help

ex-x-fire

Check the fuel pump relay for power, you'll need a wiring diagram.
If that checks ok, then check for pwr & ground at the pump.

zburnett

Fuel pressure relay ohmed out ok. Had 12v to it. Looked for an fuel pump access door.. there is none so im assuming this is a 20+ yr old fuel pump. Cant believe it finally went out lol

Randy82WS7

there is no access for FP on gm cars nope
have to yank tank out of car to replace pump


check or try another FP relay

check fuse too

is there a single fuse holder on pass side fender under the hood at top of fender? an 89 should have this fuse on the fender its in a black little case plastic rubber whatever thingy there by itself



if so then it coul dbe burnt, it happens commonly on these and its the FP fuse

there is also a relay for FP

sometimes they fail

jump orange wire to the light gray wire and see if pump runs then

orange is supposed to be hot all the time even when key is off

gray is straight to the FP

if it doesnt run then wire is broken somewhere or pump is failed

make sure gray wire is hot at tank conector under back of car when its priming for a couple seconds when key is put in run position, or when you have jumped orange and gray wires together

full 12 volts also

if its less than 12 volts then it will be weak or no fuel

the pump needs full voltage


i have sene this gray wire be faulty somewhere along length of the vehicle and be the cause of no fuel, and end up not being because of failed pump

mostly hapens on the late 80s to late 90s trucks and blazers though


ive had to replace this wire on many of them over the years

somehow it fails randomly dont know why.,

maybe from high stress voltage draw for so many years

make sure ground to pump is good strong too

just as important as full 12v to it


four wires to FP relay

the green wire to the FP relay is signal from ecm to energize the FP relay and run the pump

black is ground

and the other two are aforementoned

if you run hot to the green wire at the relay it will do same as jumping orange and gray to each other,
it will run the FP

zburnett

Thanks for the help! unfortunetly I checked the fuse, relay, and can hear the pump barely run this morning. Checked the shrader valve...and gas just dribbled out. This cars been sitting for months due to deployment. So I figured after all this sitting that it makes pressure just not much at all. Iam going to do it the proper way though and get a fuel pressure guage today.

ex-x-fire

Try banging on the gas tank, sometimes they'll start working.