Wishmaster's87IROC

iTrader: (4)

Havent been here in a while....I think my fuel pump finally died.....

was coming home one night and car was low on gas, figured I would just put some gas in the morning like I normally do...its common for me to run it low..pulled in the garage like normal. went to bed....woke up to crank the car up and warm it up in the morning, ran like it was about to run out and died, cranked it back up and ran for a sec or 2 and died.....hasnt cranked since!.......when I turn the key I cant hear the fuel pump humming at all like I used to....checked my fuel pressure and its at zero..checked the relays and the fuse and they all check out OK....anything else to check as far as power to the pump?

what else can I check to make sure that the fuel pump is dead before I go dropping the tank and replacing the pump and then finding out it still wasnt the pump?

86Z

iTrader: (4)

just the connections are left to check, did you apply 12volts to the test terminal?

Wishmaster's87IROC

iTrader: (4)

test terminal? wheres that?

86Z

iTrader: (4)

go here

Wishmaster's87IROC

iTrader: (4)

thanks for the link......how do I apply 12v to the terminal? whats the best way? so I can try that to see if the pump comes on...

thanks!

John 89 Formula

Run a piece of wire from terminal g to the battery terminal in the fuse box.

Wishmaster's87IROC

iTrader: (4)

I did that and got it to crank.......and turned the car off and got it to crank again but it slowly cut off.....as the fuel in the line ran out...I watched my fuel pressure drop....then I tried the wire again to get it to crank and now cant even get it to crank that way....so whats up with it? got any ideas? is the fuel pump bad? as well as some kind of connection? I went and got a new relay from Advance and that didnt help.

1989GTATransAm

iTrader: (3)

Fuel Filter?

RednGold86Z

iTrader: (1)

put fuel in the tank?

Did you run the battery dead, or what do you mean can't get it to crank?

Wishmaster's87IROC

iTrader: (4)

I jumped the G terminal got it to crank..and get it run a for a few minutes. Then I shut the car off and cranked it back up and let it run....it ran until I guess the gas in the line ran out and then it shut off. Then I jumped the G terminal again and it wouldnt crank...I couldnt hear the pump come back on.. No I didnt run the battery dead and yes it had fuel in it.....So why doesnt jumping the G terminal turn the pump on anymore?


Im a t a stand still and I dont think its my fuel pump....I dont want to go thru the trouble of changing it and finding out its not the pump.

86Z

iTrader: (4)

sorry dude but most likely it's the fuel pump, i just installed one and hope to not do it again anytime soon, what was the fuel pressure at the rail when you jumped the pin g?

John 89 Formula

If your fuel pump is still working, get a noid light and test the injector harness. If the light doesn't flash while cranking then chances are your ignition module died, and this is a heluva lot easier to change than a fuel pump.

Wishmaster's87IROC

iTrader: (4)

but I get no fuel pressure...its at ZERO......so that means gas is not making it to the injectors...right?

RednGold86Z

iTrader: (1)

If you're in a quiet enough place, you should be able to hear a humm from the pump once you power it.

Also, once you power it, check for voltage at the wires that actually go directly to the pump (G). Maybe your jumping from a bad source, or have blown a fuse doing it.

If the engine did sorta start, that means the injector wiring and injectors shouldn't be the problem.

It's almost definitely something wrong with the pump or the wires/control relays going to it. I've never heard of a filter completely clogging in a short time, so highly likely that it's not the cause.

91Z28TTOP

Try this....assuming you have an oil pressure switch threaded just above the oil filter. Unplug it and pull the plug up towards the top of the engine. If it has three female connectors they should be in a triangle two top and one bottom. Using a small piece of wire loop it and plug each end into the two top connectors. It should make the fuel pump run. If not then its one of the top connectors and the bottom one. If you don't have an oil pressure switch Look under the car for the fuel pumps hot wire and trace it towards the engine. It could be runing next to the exhaust and has chaffed and now grounding out. Hope this helps.

Black Knight

I am going to Hijack the thread because I have a similar problem on my 89. When I crank the ignition I get no fuel coming out the lines. I tried jumping it, as someone said above, but all I hear is clicking from the fuel pump relay, no humming from the pump.

My car has been sitting for a while, could the pump have failed from sitting?

91Z28TTOP

There is either two or three relays on the fire wall, driverside between the fender and the brake booster. One is the fuel pump relay and the other(s) are for the fans. Try switching them around and see what results you get. Also have you checked to see what codes the computer is throwing?

Black Knight

Thanx for the reply
Actually I switched them around and got the same results. I have not checked the codes, as since I put the car away I never tried starting it till recently, when I had the above problem, but I will check tomorrow.

Wishmaster's87IROC

iTrader: (4)

I just purchased a walbro 255hp fuel pump...so Im just going to drop the tanks and replace it.....let me ask..if I disconnect the weather pack under the car that leads to the fuel pump...how can I throw power to the pump?....its a 3 prong connector....I just want to make damn sure its the pump.


thanks!

Synapsis

Yes. The Grey wire is +12 to the pump, the black is ground. (The purple is for the fuel level sender, 0-90 ohms resistance IIRC.)

Wishmaster's87IROC

iTrader: (4)

So when I unplug it how can I throw power to it? Im stupid when it comes to stuff like this...can I use a battery?

Synapsis

Well, you need 12 volts. So if you have a car battery lying around you can put the + (the red wire on the battery) on the grey wire and the - (the black wire on the battery) on the black wire and it should run.

Wishmaster's87IROC

iTrader: (4)

yeah I got an old battery laying around....will do..thanks!

and if the pump comes on?..then the problem is somewhere else, huh?...

Synapsis

A pump can have flow but be too weak for pressure. Running your tank so low all the time didn't help the pump any. In-tank fuel pumps are cooled by the fuel around it, so when you run it low it'll overheat. That's why mine failed. I was running the tank low to swap fuel and the pump overheated.

Wishmaster's87IROC

iTrader: (4)

well like I have said above, I checked and replaced all the relays and fuses...still no humming from the fuel pump...I then did the jumping of the G terminal and got it to hum and crank one time but it hasnt cranked or hummed since.....I even took the fuel filter completly off and just left the lines open and tried to cranks it to see if the filter was clogged and maybe fuel would start flowing but nothing...so my last resort is to throw power directly to the pump the way you said and if it the pump doesnt start then I know its the pump...Im kinda hoping it doesnt come on cause I would hate to try and trace where the problem is....

Firebird sweden

Check the short rubber fuellines betwen the pump and the hard lines (in the tank),make sure to replace them if you swap the pump,those can look fine but often they are the real trubble,becouse the small cracks in the rubber are not letting the pump to build up any pressure.Thats why it starts for a while and die.
From personal experiens,i have to take the tank down 3 times before i lokated the cracks
Anders

orod

I'm in same place right now. my question is i pulled 11.54 volts from the battery, than pulled the same voltage under the dash and tried to jump the pump(same 11.54) , didn't work and went under the car before the tank and pulled 7.02 volts. is that 7 volts enough to power the pump or did i miss something somewhere?

Firebird sweden

Why are you only getting 7 volt,is it from the battery in the car or is it an external battery,i think 7 volt is not inogh to get it turning.
Recharge the battery and try again,in my car there vere no testcable for the fuelpump in the diagnostic hose.
(sorry for my spelling)

Wishmaster's87IROC

iTrader: (4)

well I finally got around to testing the fuel pump with putting power directly to it via another car battery I had laying around...so I ran a wires off the battery straight to the fuel pump connection and ...NOTHING!...the pump didnt come on...SO its oviously the pump.....now Im waiting on a Walbro 255hp pump to come in so I can tackle the job of replacing it....fun fun!!!


Hey, will my new pump make my car run alot better? seeing that the other was apparently going bad.....will I notice a difference?

1QUIKTA

Wishmaster, was the pump the problem? I am in the same boat. I jumped the G terminal and also ran a wire straight to the fuel pump positive. I only had 11.6 volts, but I figured that would be enough. Nothing at all. Just replaced filter, injectors and all "tune up" parts.

Let me know,
Chris