Fuel pump does not come on during first crank
Thread Starter
Pro
Joined: Sep 2002
Posts: 715
Likes: 2
From: Mooresville NC
Fuel pump does not come on during first crank
Hi,
I noticed that my 99 Corvette would not start until the second or third try. While looking for other symptoms, I noticed that the fuel pump was not coming on during the first crank and sometimes during the second crank. It also has zero fuel pressure during this time. My workaround has been to just cycle the key to "On" and then to "Off" two or three times until I hear the fuel pump, and then it starts right up. Anybody know what this could be? I tried swapping the fuel pump and horn relays and that didn't help. Thanks.
I noticed that my 99 Corvette would not start until the second or third try. While looking for other symptoms, I noticed that the fuel pump was not coming on during the first crank and sometimes during the second crank. It also has zero fuel pressure during this time. My workaround has been to just cycle the key to "On" and then to "Off" two or three times until I hear the fuel pump, and then it starts right up. Anybody know what this could be? I tried swapping the fuel pump and horn relays and that didn't help. Thanks.
Tech Contributor
Joined: Jan 2007
Posts: 19,493
Likes: 1,178
From: Dyer, IN
I would get a meter on the LH fuel level/pump assembly connector, and see if you have a good ground at pin D. Then you can verify if you have 12 volts at the connector (pin A) for that initial crank, or if the voltage remains at zero. Just turning the key to the on(run) position will turn the pump on for 2 seconds.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I agree 
,,your going to need to do some meter reading and ground cleaning. On a car thats as old as yours, its a very good idea to clean chassis grounds G-101, 102, 104, & 401. G-401 is the actual fuel system ground.
Something else that can cause this issue is the ignition switch.
Use a DC Volt meter and check the voltage at the "Under Hood Fuse Block, fuse #13, F/PMP 20 amp for voltage. LOOK ON TOP OF THE FUSE AND YOU WILL SEE TWO TEST POINTS. When you turn the key to ignition ON or START,,,there should be 12 DC battery voltage on both test points. If there ISN'T,,,,,the ignition switch could very well be causing the issue. When the fuel pump doesn't come on, do this test and see if there is or isnt voltage there during the fault.
If thats the case I have a post that explains how to clean and repair that switch for free.
,,your going to need to do some meter reading and ground cleaning. On a car thats as old as yours, its a very good idea to clean chassis grounds G-101, 102, 104, & 401. G-401 is the actual fuel system ground. Something else that can cause this issue is the ignition switch.
Use a DC Volt meter and check the voltage at the "Under Hood Fuse Block, fuse #13, F/PMP 20 amp for voltage. LOOK ON TOP OF THE FUSE AND YOU WILL SEE TWO TEST POINTS. When you turn the key to ignition ON or START,,,there should be 12 DC battery voltage on both test points. If there ISN'T,,,,,the ignition switch could very well be causing the issue. When the fuel pump doesn't come on, do this test and see if there is or isnt voltage there during the fault.
If thats the case I have a post that explains how to clean and repair that switch for free.
