Vacuum Leak 1985 corvette
Thread Starter
Intermediate
Joined: Apr 2013
Posts: 40
Likes: 0
From: Culver City CA
Vacuum Leak 1985 corvette
Hello all,
ok i have narrowed down my rough idle to a vacuum leak. where? i have no clue so i ask can anyone provide a diagram or link to a diagram that shows the location of vacuum hoses i should check.
thanks all.
a bit more info on my issue.. rough but not that rough of an idle while in drive, reverse etc. in park its ok but its still sporadic. under acceleration there is no issues nor under WOT.
thanks again..
ok i have narrowed down my rough idle to a vacuum leak. where? i have no clue so i ask can anyone provide a diagram or link to a diagram that shows the location of vacuum hoses i should check.
thanks all.
a bit more info on my issue.. rough but not that rough of an idle while in drive, reverse etc. in park its ok but its still sporadic. under acceleration there is no issues nor under WOT.
thanks again..
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: Apr 2013
Posts: 40
Likes: 0
From: Culver City CA
ok i have looked at every hose and for the most part they look brand new. maybe its the idle control? i am also getting a good whiff of fuel coming from the exhaust. its running a cat converter so i am unsure if that smell is normal for a car this old or not? any other ideas guys?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Remove the vacuum line from the fuel pressure regulator and see if it has fuel in it. If it does then the FPR diaphragm is ruptured.
If you need a visual aid to find the FPR, here's one after my FPR ruptured and sprayed fuel on the engine which then caught on fire. All the white stuff is fire extinguisher powder. The FPR is just to the left of the fuel pressure gauge (you won't have one of these on your car -- I added it). The dark black part is where the vacuum hose was attached before fuel pressure blew it off.
If you need a visual aid to find the FPR, here's one after my FPR ruptured and sprayed fuel on the engine which then caught on fire. All the white stuff is fire extinguisher powder. The FPR is just to the left of the fuel pressure gauge (you won't have one of these on your car -- I added it). The dark black part is where the vacuum hose was attached before fuel pressure blew it off.
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
Pay real close attention to all the hoses that are down in the lower left corner of the picture provided by tunedport85inject, that area is notorious for having the hoses go bad. If you feel around down in there and your hand comes away completely black it's time to replace all of them in that area.