luvmy64

Oh great gods of the thirdgen:

1989 Rs, 305 TBI, cranks when pouring gas in the TB, unhooked the fuel lines, and nothing coming out when i turn the key. Cant hear the fuel pump kicking on, but dont know if it is or isnt. Just bought a new fuel pump/filter etc thinking that may be the problem, but i seem to remember something about wiring a 12v source to the "G" terminal on my ALDL to allow the pump to run. Any info on this is appreciated. Also, could this be a VATS problem, since it will run while pouring gas in it? By my thinking, if the chip in the key will keep it from getting fuel, then it will also keep it from turning over.

Also also, where is the fuel pump relay and how do i check it?

Ive dropped a tank on these cars before and its something i dont wanna have to repeat unless absolutely necessary.

If I havent provided enough info, let me know.

Werewolf SS

iTrader: (3)

The relay is located on the driver side firewall and there are three relays there. It should be the middle one. I had the same issue when I bought my TBI and replaced the fuel pump.
Wiring 12v is for people who have gone to carb and want the fuel pump to run when the car key is in the on postion at all times instead of being run from the oil pressure signal. Fuel relay is cheap to replace but more than likely it's the fuel pump. It's a common issue with these cars the fuel pumps don't go 20 years stock plain and simple.
you can either cut a fuel access door in the trunk (do a search and be careful when doing this) or drop the fuel tank.
Droppping the tank is (FUUUUNNNNNN) you have to remove the rear pipe remove the back panhand bar and then loosen the tank straps and slowly pull hir down (fighting the whole way). You'll need a second set of hands to do this especally if you have gas in the car.

luvmy64

Yes, I have done the whole drop the tank thing before.......I know its a PITA........
How do I check the relay, though?

Werewolf SS

iTrader: (3)

Not any real way to test the relay other than to replace it.
When you turn the key do you hear the relay making a clicking noise?

luvmy64

I havent listened for the clicking in the relay, but i have unscrewed the fuel lines going to the throttle body, and there is nothing coming out, even though the motor is turning over.......

camaronewbie

The relays for the fan and the fuel pump are usually the same relay. The fan relay has a large black wire red stripe, fuel pump relay doesn't. Mark the fan relay (the good one assuming your fan works), and swap the two. Can you hear the fuel pump prime now? If it does, then the relay is bad, if it doesn't then the fuel pump is dead.

I hate to say it, but I'm guessing the fuel pump is dead. Why? When cranking, even if the relay is bad, the Oil Pressure Sending Unit should run the pump as soon as it senses oil pressure (from the motor turning over). Since no fuel while cranking, sounds like a bad pump.

OH - WAIT - maybe the fuse for the fuel pump wiring is bad - driver side, tucked in fender between battery and fender - red wire in, orange wire out, with a fuse inside a weatherpack - check that fuse before you go farther!

luvmy64

Mystery solved. Dropped tank, and its rust city in there. Also, rubber hose inside tank was shot.
As if that werent bad enough news, PO actually removed the fuel filter and put in a piece of hose where it used to be (im assuming to see if that was why it wouldnt crank).
I blew out all the lines with air....now i just have to hope my injectors are still ok.

UnderCover89TBI

iTrader: (25)

I have decided next time I do my pump I am going to cut out the rear hatch area floor and be able to change my pump in an hour instead of a couple hours. especially with the upgrades ill be doing someday.

luvmy64

I swapped in the 4th gen tank, wont have to worry about rust anymore. Its a pretty straightforward swap, but the mounting straps are a PITA for some reason.

I went ahead and cut the hole, too. Im NOT dropping that friggin tank again!

UnderCover89TBI

iTrader: (25)

great work man!

luvmy64

New problem: Injectors not pulsing when i crank it over. Ive got gas coming out near the engine at the return line, so I know its getting that far.......

Somebody jog my memory: the last one of these i messed with pulsed the injectors when i grounded a certain wire (or wires) out that goes to the injector itself. Does anybody know which wire i need to ground out for the injectors to pulse?

Am I looking at a VATS problem? It turns over, but no pulse. Would ohming out the chip in the key and putting the correct resistor in the line yield a good result?

UnderCover89TBI

iTrader: (25)

not sure on the wires. are you getting spark? the igntion control module does control both. I have seen it go bad and lose only one, or both.

luvmy64

Ive got spark, because i can crank it with gas poured in the throttle body.

UnderCover89TBI

iTrader: (25)

okay. it could still be a bad ignition control module, that also controls the injector pulse.

luvmy64

OK...so do I start with a noid light and check the injectors first to see if they are getting a signal to pulse and work backwards from there? I seem to remember that one side of the injector is constant 12v, and the ecm grounds the other side to make the injector spray...right?

quickkris2006

iTrader: (2)

its the vats been there done that.. find out the vat code u need..

UnderCover89TBI

iTrader: (25)

You really think its the vats. Because everytime my vats system has messed up. It hasnt stopped the car from running. It stops the car from cranking over. turning off the starter. But okay.

luvmy64

NOT VATS......
Got the noid light. one injector was seeing pulse, one wasnt. Replaced fuse of injector that wasnt, beat on injectors with wrench, fired right up.

Sometimes its the simple crap........