C5 Fuel injection manifold
Thread Starter
Racer
Joined: Sep 2016
Posts: 266
Likes: 59
From: Williston Florida
C5 Fuel injection manifold
I have removed the intake to replace the knock sensors and harness, in the back of the manifold there is a 'plug?' with the MAP sensor mounted on it. The part of the manifold that the MAP is on is loose, I tried light force to see if it is removable but it resists movement in either direction. Is this part supposed to be loose?
Acct Suspended APR 2026 by request
Joined: Dec 2010
Posts: 10,367
Likes: 1,272
2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
some of them have a bit of movement, use some clear silicone around that area and it will seal up any leaks
Thread Starter
Racer
Joined: Sep 2016
Posts: 266
Likes: 59
From: Williston Florida
Thanks guys, that's a big help, and I was wondering about the vacuum hose, too. It separated when I finally got the manifold out far enough to see what was making it difficult. I decided to replace the MAP also, I could see it failing soon and I would have to go back in to replace it. I wanted to also replace the cam sensor, but I can't find one listed for the 98, The ones listed for the 99 say it won't work on the 98. I cleaned it up and gave it a good look, usually, when those sensors are going to fail they have cracks in the plastic. mine looks OK, so I'll take a chance on it.
The front knock sensor was heavily corroded, it looks like it was in water for a long time. I checked on that issue and found the recommendation to make a silicone dam around it with a gap in back. Someone has been there before me and didn't re-attach the clips for the wire looms, and the manifold bolts weren't even finger tight.
The front knock sensor was heavily corroded, it looks like it was in water for a long time. I checked on that issue and found the recommendation to make a silicone dam around it with a gap in back. Someone has been there before me and didn't re-attach the clips for the wire looms, and the manifold bolts weren't even finger tight.
Last edited by sjhanc; Apr 7, 2020 at 08:55 PM.
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,442
Likes: 2,187
From: Buffalo Texas
I always install the steam line kit when I remove the intake, cooling system works much better !!! https://www.summitracing.com/parts/tfs-306sb601
Melting Slicks
Joined: Oct 2010
Posts: 3,030
Likes: 794
From: Tollesboro Kentucky
I always install the steam line kit when I remove the intake, cooling system works much better !!! https://www.summitracing.com/parts/tfs-306sb601
Melting Slicks
Joined: Mar 2018
Posts: 2,502
Likes: 187
From: California
What your referring to is a pain in the rear to get to and it does not come out easily it will turn but there are two locking tabs on the inside u must have a thin long pair of angles needle nose to even attempt getting it out even then it’s a real time consumer. It’s prob less effort and about 40% more to just replace the intake manifold. I have a extra piece that round one with the fitting all new but I have gave up trying to get it out and repair my intake long ago good luck
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
Melting Slicks
Joined: Mar 2018
Posts: 2,502
Likes: 187
From: California
Hopefully you bought the original knock sensors because these cars do not like aftermarket stuff again experience I still have no knock sensors working ! And it’s boosted tuned without them and I have mine so desensitized it’s pitiful
Thread Starter
Racer
Joined: Sep 2016
Posts: 266
Likes: 59
From: Williston Florida
After several weeks of driving in temps up to 100 F I can report that the Hi-temp epoxy for plastics worked fine to glue that rear plug in tight. It shows no sign of failure. After cleaning the manifold I left it sit under the sun to dry the water, and also heat it up to make the epoxy kick sooner. I mixed more than needed for the glue job and poured it around the outside of the plug, then let gravity pull the glue into the joint. As the glue began to slow down and grip I poured the rest around the outside seam to thicken the glue joint. Looks like a fix.