howling fuel pump
Thread Starter
Intermediate
Joined: Jan 2019
Posts: 37
Likes: 0
From: Athens TN
howling fuel pump
yesterday wife and I took our new to us 1985 c4 for a ride to Knoxville to show the grandkids the car. the car run great 75mph highway about 50 miles no problems just before pulling in there drive way we heard a loud howling noise coming from rear of car got out and fount noise coming from under gas cap must be fuel pump. shut off car let it set 5 min. turned on no noise. Anybody seen this? could fuel pump be going? if so what is the new pump choices? thanks for help
Le Mans Master
Joined: Feb 2005
Posts: 6,479
Likes: 565
From: Clearwater Florida
….. I suspect that the fuel tank vent is not working … Evap + charcoal canister … what you heard was probably air being sucked into the tank either through or around the filler cap …..
Le Mans Master
Joined: Feb 2005
Posts: 6,479
Likes: 565
From: Clearwater Florida
….. The Factory Service Manual has the complete troubleshooting flow chart for the EECS … Evaporative Emissions Control System … But the most common issue is the vent tube that runs from the fuel tank to the charcoal cannister … it is fairly small in diameter and made of steel and is prone to getting clogged by rust and other gooey byproducts of evaporating fuel … try disconnecting it at both ends of the car and blow compressed air from the rear to the front … if you can isolate the crud from entering the fuel tank , you can try blowing air in both directions … once the air is flowing , the tank is vented again and should stop your whistling/howling noises as you consume fuel from the tank …..
Thread Starter
Intermediate
Joined: Jan 2019
Posts: 37
Likes: 0
From: Athens TN
No noise stopped with cap off but there was a lot of pressure behind cap I am thinking plugged tank vent might be the right call we are getting some nice weather down hear in SE TN over the next couple of days and I am going to do the testing and cleaning evap system I also have a hole lot of vacuum lines to replace that might take care of a interrelate surging idle I am having as well.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Intermediate
Joined: Jan 2019
Posts: 37
Likes: 0
From: Athens TN
C409 I think you were wright I could not blow through vent line at the fuel tank so I sprayer carb cleaner in hose and used compressed air and got a bunch of rusted crud out hope that takes care of it I am replacing all my vacuum hoses tomorrow they are shot. Thanks for your help