fuel pump problem?
Thread Starter
6th Gear
Joined: May 2011
Posts: 6
Likes: 2
fuel pump problem?
My C5 six speed has had trouble starting lately. It has always fired up promptly on the first turn of the key. In the last two weeks it takes two tries to do the job when cold. It will frequently fire up normally when warmed up. The car runs fine once started, so is this an indication of a failing fuel pump, or something else? The battery is charging OK and the starter cranks strong. Thank you for any light you can shed on my problem.
Drifting
Joined: Sep 2009
Posts: 1,719
Likes: 4
From: cinnaminson n.j.
St. Jude Donor '14
If you are able to, leave the pressure gauge on overnight. See if it reads low or 0 before turning the key on or cranking. Have someone turn the key on and wait while you watch the gauge. The pump will prime for 2 seconds. Then have then crank it and watch the gauge. If it takes a while (5 seconds or more) for the pressure to reach 56-60 psi, your check valve has failed. The fuel bleeds back threw the valve. As long as the engine runs well under load, the pump is fine.
I had the same problem on my 2000. Changed the check valve and now it starts instantly even if it's sits for a week.
If your car is older and has the 2 line system it can also bleed past the regulator on the rail, but it's not likely.
I had the same problem on my 2000. Changed the check valve and now it starts instantly even if it's sits for a week.
If your car is older and has the 2 line system it can also bleed past the regulator on the rail, but it's not likely.
Burning Brakes
Joined: Feb 2007
Posts: 899
Likes: 130
From: Kerrville, Texas
My C5 six speed has had trouble starting lately. It has always fired up promptly on the first turn of the key. In the last two weeks it takes two tries to do the job when cold. It will frequently fire up normally when warmed up. The car runs fine once started, so is this an indication of a failing fuel pump, or something else? The battery is charging OK and the starter cranks strong. Thank you for any light you can shed on my problem.
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
If you are able to, leave the pressure gauge on overnight. See if it reads low or 0 before turning the key on or cranking. Have someone turn the key on and wait while you watch the gauge. The pump will prime for 2 seconds. Then have then crank it and watch the gauge. If it takes a while (5 seconds or more) for the pressure to reach 56-60 psi, your check valve has failed. The fuel bleeds back threw the valve. As long as the engine runs well under load, the pump is fine.
I had the same problem on my 2000. Changed the check valve and now it starts instantly even if it's sits for a week.
If your car is older and has the 2 line system it can also bleed past the regulator on the rail, but it's not likely.
I had the same problem on my 2000. Changed the check valve and now it starts instantly even if it's sits for a week.
If your car is older and has the 2 line system it can also bleed past the regulator on the rail, but it's not likely.
Good recommendations!!Also do as 8VETTE7 recommended and check and post your DTCs. Checking the DTCs is always a FIRST Step anytime your car has any issues.
BC
Last edited by Bill Curlee; Jul 25, 2014 at 10:41 AM.
