90 Vette Stalling
Thread Starter
Safety Car
Joined: Mar 2005
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From: Winnipeg Manitoba, Canada
Sorry but I dont understand what you mean. This test should make the fuel pump stop after two seconds? Does this prove anything?
Thread Starter
Safety Car
Joined: Mar 2005
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From: Winnipeg Manitoba, Canada
I touched every wire at the pump with my test light and it doesnt turn on. The key is on. What color is the 12v source at the pump, purple?
Supporting Vendor
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From: Cumming Ga
the light will only go on for 2 sec. when the ecu picks up cranking the pump should run untill the engine is shut off. my feeling is that the pump is not running during cranking. alowing the engine to start and die immediatly. (i think thats what you said) so the test light should be on if hooked to the right wire during cranking and stay on through startup. look at the plug in the back where the fuel pump plugs in. if you just turn the key the power is interupted.
Le Mans Master
Joined: Jul 2007
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From: Tampa Florida
The "Apply 12v to terminal G of the ALDL".....this will apply 12 to the fuel pump circuit( pump will run while voltage is applied to "G" of the ALDL) is done by running a single wire from the + terminal of the car's battery to the "G" terminal of the ALDL connection point under the driverside panel. This means that the fuel pump will run regardless of the key switch position as long as you have 12 volts on "G".
Thread Starter
Safety Car
Joined: Mar 2005
Posts: 4,723
Likes: 11
From: Winnipeg Manitoba, Canada
the light will only go on for 2 sec. when the ecu picks up cranking the pump should run untill the engine is shut off. my feeling is that the pump is not running during cranking. alowing the engine to start and die immediatly. (i think thats what you said) so the test light should be on if hooked to the right wire during cranking and stay on through startup. look at the plug in the back where the fuel pump plugs in. if you just turn the key the power is interupted.
Thread Starter
Safety Car
Joined: Mar 2005
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From: Winnipeg Manitoba, Canada
My bad it was a bad explanation....this may not be any better but......The fuel pump/Fuel pump relay will only run/close for 2 seconds once the key switch is turned from the "off" postion to the "run" position without rotating the key to the "start"/cranking position....this is normal.
The "Apply 12v to terminal G of the ALDL".....this will apply 12 to the fuel pump circuit( pump will run while voltage is applied to "G" of the ALDL) is done by running a single wire from the + terminal of the car's battery to the "G" terminal of the ALDL connection point under the driverside panel. This means that the fuel pump will run regardless of the key switch position as long as you have 12 volts on "G".
The "Apply 12v to terminal G of the ALDL".....this will apply 12 to the fuel pump circuit( pump will run while voltage is applied to "G" of the ALDL) is done by running a single wire from the + terminal of the car's battery to the "G" terminal of the ALDL connection point under the driverside panel. This means that the fuel pump will run regardless of the key switch position as long as you have 12 volts on "G".
Supporting Vendor
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From: Cumming Ga
the pump should always run when the engine is running or cranking. Does yours run at all times.. tell us what its doing,, its probably the relay if its stopped.. i don't think its the punp
Thread Starter
Safety Car
Joined: Mar 2005
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From: Winnipeg Manitoba, Canada
I'm trying to figure out if its running when it starts, but I'm having a bit of difficulty! I can also change out the relay and see if it helps.
Last edited by jimmers; Sep 21, 2008 at 03:14 PM.
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Supporting Vendor
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From: Cumming Ga
Le Mans Master
Joined: Jul 2007
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From: Tampa Florida
Pop the hood.....the relay is on the firewall about 1/2 between the brake booster and distributor. You should be able to locate the relay by listening for the "tic" sound from the relay after it drops out ~2 seconds after you turn the key to the "run" postion.
Thread Starter
Safety Car
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From: Winnipeg Manitoba, Canada
Well I went outside to test for 12v at the fuel pump wire and it started right up and ran fine. It ran for 10min before I shut it off. The fuel pressure is holding steady still. Now I'm really lost.
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From: Cumming Ga
did you play with the wires.. i bet if you take apart some of the connectors back by the pump you will find that green toe jam. (corrosion) pull the relay and check all the connectors and wiring. I think you at least know the source of the problem.. you need constant fuel pressure to keep the engine running
Le Mans Master
Joined: Jul 2007
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From: Tampa Florida
Thread Starter
Safety Car
Joined: Mar 2005
Posts: 4,723
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From: Winnipeg Manitoba, Canada
I went for a ride around the block, stalled on me. I kept starting and starting it before it finally stumbled home. Stalled on me on the driveway a few times. I hit the fuel pump and it seems to help a bit.
Last edited by jimmers; Sep 21, 2008 at 04:18 PM.
Thread Starter
Safety Car
Joined: Mar 2005
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From: Winnipeg Manitoba, Canada
I hooked up my 12v light again and started the car.
The light will turn on while the car is running. When the car stalls the light will remain lit, and turn off about 2 seconds later. So I guess the pump is getting a good 12v source.
Seeing as how the pump dies before the light, I can assume that the fuel pump itself is bad. Correct?
The light will turn on while the car is running. When the car stalls the light will remain lit, and turn off about 2 seconds later. So I guess the pump is getting a good 12v source.
Seeing as how the pump dies before the light, I can assume that the fuel pump itself is bad. Correct?
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
I hooked up my 12v light again and started the car.
The light will turn on while the car is running. When the car stalls the light will remain lit, and turn off about 2 seconds later. So I guess the pump is getting a good 12v source.
Seeing as how the pump dies before the light, I can assume that the fuel pump itself is bad. Correct?
The light will turn on while the car is running. When the car stalls the light will remain lit, and turn off about 2 seconds later. So I guess the pump is getting a good 12v source.
Seeing as how the pump dies before the light, I can assume that the fuel pump itself is bad. Correct?
Thread Starter
Safety Car
Joined: Mar 2005
Posts: 4,723
Likes: 11
From: Winnipeg Manitoba, Canada
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
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From: Cumming Ga
Thread Starter
Safety Car
Joined: Mar 2005
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From: Winnipeg Manitoba, Canada
I'll try and get one tomorrow. Will a stock pump be enough seeing as how the engine has been rebuilt and puts down about 310hp to the wheels. Do I need a pump that flows more? Thanks for your help!
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From: Cumming Ga