Fuel pump Problem!
Thread Starter
Racer
Joined: Oct 2006
Posts: 305
Likes: 0
From: Hilmar Ca
Fuel pump Problem!
So car was towed yesterday! I thought it was because it ran out of gas. But today it has about 3 gallons and still wont start! Well I took apart that gas lid and check the wires. One has ground the other has power and the shows nothing. I disconected hoses one by one and cranked the car. Nothing came out??? is the fuel pump bad?
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Have someone turn the key "on" but not start the motor while you listen in at the gas cap. Can you hear the pump prime? It should be a smooth hum lasting about 2 seconds. If you hear a crappy gurgle, or no prime, then yeah the pump is probably dead.
Check for fuel pressure and spark also.
Check for fuel pressure and spark also.
Safety Car
Joined: Jul 2004
Posts: 3,834
Likes: 30
.......could be (if applies) fuel pump relay went bad.....apply +12vdc to the aldl and that should send power directly to the fuel pump...at that point crank th ecar and see if that works...if it does, i'd be looking at the realy...if it doesn't, i'd be looking at a defective fuel pump or bad wiring....
To engage the Fuel Pump
connect a fused (+) lead to terminal G of the aldl- This will cut the fuel pump on. This verifies that the pump is in working order.
To engage the Fuel Pump
connect a fused (+) lead to terminal G of the aldl- This will cut the fuel pump on. This verifies that the pump is in working order.
Last edited by Da Mail Man; Aug 9, 2007 at 08:16 PM. Reason: additional
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Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Find a 12 volt source, like the battery positive terminal, and apply to the G terminal using a long jumper wire.
Or,
Just unplug this relay. It's the fuel pump relay. If auto, there is only one. If manual, there is two. I think it's the one closest to the driver's side if two. Wires are Red, Orange, Red again, Green w/white, Black w/white.
Jump a wire between terminals A and E (Red and Orange) of the relay connector. Key on or off. This will feed voltage directly to the pump as soon as the wires touch. Pump should prime.
Check the fuel pump fuse labeled "FP Fuse" also.
Safety Car
Joined: Jul 2004
Posts: 3,834
Likes: 30
....it does not matter if the ignition is on..if you apply 12vdc to the terminal, crank the car and see if it starts......if it doesn't, looks like it could be a fuel pump issue......say, have you ck'ed the fuses in the fuse panel as i think there are some that would "apply"....also, do you have a fuel pressure gauge?.if so, put it on and apply the 12vdc as above...if you don't have pressure, i'd say your pump crapped out....
Thread Starter
Racer
Joined: Oct 2006
Posts: 305
Likes: 0
From: Hilmar Ca
I have a brand new relay in my tool box that I keep. I put it in place of the fuel pump relay already and still nothing... I will try applying power to the G wire and let you know what happens!
Safety Car
Joined: Jul 2004
Posts: 3,834
Likes: 30
...if you have applied +12vdc to the correct pins of the aldl,
...if you are sure connections are good,
...you have no fuel pressure,
...you have gas in the tank and of sufficient quantity,
...you changed out fuel filter,
...you cannot hear pump prim or run,
...then, the pump is probably BAD
Pro
Joined: Nov 2006
Posts: 727
Likes: 0
From: Ocean City Maryland
....it does not matter if the ignition is on..if you apply 12vdc to the terminal, crank the car and see if it starts......if it doesn't, looks like it could be a fuel pump issue......say, have you ck'ed the fuses in the fuse panel as i think there are some that would "apply"....also, do you have a fuel pressure gauge?.if so, put it on and apply the 12vdc as above...if you don't have pressure, i'd say your pump crapped out....
You never mention what year it is but I just went through this, I replaced the fuel pump relay, still not the issue, then replaced the fuel pump and pulsator, was a hard starting issue because, like you it finally left me towing. turns out the in addition to the fuel pump, it was the O2 senor and the MAF. Not sure what your syptoms are but try to disconnect the MAF and see if it starts. The FSM is cool but confusing. Now my car is running great until the next major malfunction, but I unstand more of the syptoms.
Safety Car
Joined: Jul 2004
Posts: 3,834
Likes: 30
You never mention what year it is but I just went through this, I replaced the fuel pump relay, still not the issue, then replaced the fuel pump and pulsator, was a hard starting issue because, like you it finally left me towing. turns out the in addition to the fuel pump, it was the O2 senor and the MAF. Not sure what your syptoms are but try to disconnect the MAF and see if it starts. The FSM is cool but confusing. Now my car is running great until the next major malfunction, but I unstand more of the syptoms.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Yeah, to put the final nail in the coffin, the Tan w/white wire under the filler neck mat is the fuel pump voltage feed.
Take a voltage reading there when you either bypass the relay with a jumper wire, or energize terminal G of ALDL. That should be the end of it.
http://forums.corvetteforum.com/show....php?t=1718223
Take a voltage reading there when you either bypass the relay with a jumper wire, or energize terminal G of ALDL. That should be the end of it.
http://forums.corvetteforum.com/show....php?t=1718223
Thread Starter
Racer
Joined: Oct 2006
Posts: 305
Likes: 0
From: Hilmar Ca
Well I didnt jump the relay wire or apply it to the G wire, because with simple turn of a key one of the wires has a 12 volt back their!
There should only be one wire with 12 volts right? The other is a ground and ther other I dont no! But a total of 3 wires!
There should only be one wire with 12 volts right? The other is a ground and ther other I dont no! But a total of 3 wires!