C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Need some input

Thread Tools
 
Search this Thread
 
Old Jul 4, 2011 | 12:30 PM
  #21  
hooked073's Avatar
hooked073
Melting Slicks
 
Joined: May 2010
Posts: 2,082
Likes: 3
From: Conowingo Maryland
Default

Originally Posted by 383vett
It really sounds like a vacuum leak. Did you switch runners from left to right? Not sure iif it matters on a tpi, but it does on a superram.

It does matter and a common mistake. It also sounds like this could very likey be his problem.
Reply
Old Jul 4, 2011 | 12:32 PM
  #22  
oldalaskaman's Avatar
oldalaskaman
Le Mans Master
10 Year Member
 
Joined: Aug 2010
Posts: 9,272
Likes: 17
Default

Runners on a tpi wont switch by accident, you have to work at it, at least mine didnt.
Reply
Old Jul 4, 2011 | 12:39 PM
  #23  
Casket86's Avatar
Casket86
Thread Starter
Racer
 
Joined: Apr 2010
Posts: 285
Likes: 0
From: New Prague MN
Default

If you swapped runners, you'd know. There would be no way to re-mount the cold start injector. Thanks for the ideas though.

Reply
Old Jul 4, 2011 | 12:39 PM
  #24  
joe paco's Avatar
joe paco
Burning Brakes
 
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Default

Originally Posted by hooked073
It does matter and a common mistake. It also sounds like this could very likey be his problem.
I'm curious why it matters, apparently don't seal a gasket somewhere.

One could possiby look for the rubbing, burnished mark where the left side throttle cables have rubbed. I was not sure on mine, and that was the quickest indicator.

another good reason to remove plenum only.

Last edited by joe paco; Jul 4, 2011 at 12:40 PM. Reason: "rubbing"
Reply
Old Jul 4, 2011 | 12:51 PM
  #25  
joe paco's Avatar
joe paco
Burning Brakes
 
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Default

Originally Posted by Casket86
If you swapped runners, you'd know. There would be no way to re-mount the cold start injector. Thanks for the ideas though.

didn't now that! the 91 does not have CSI. still don't know why no one has ever mentioned it as a problem to avoid.

the jokes on me! am new to this and was not thinking. the rt side runner has the hot gas tube in the middle!!! so, differnt parts, but could still be switched, maybe.

Last edited by joe paco; Jul 4, 2011 at 12:58 PM. Reason: brain kicked out of gear!
Reply
Old Jul 5, 2011 | 09:28 PM
  #26  
Casket86's Avatar
Casket86
Thread Starter
Racer
 
Joined: Apr 2010
Posts: 285
Likes: 0
From: New Prague MN
Default

I just wanted to take a minute to thank all who chimed in with ideas and advice. After fixing the issue with the passenger side runner, I developed a very noticeable hiss from the driver side up near the firewall, so after work today I started slowly dismantleing taking time to watch everything very carefully. Nothing jumped out. As I was getting ready to re-gasket and re-install I decided it might be a good idea to check the lower intake bolts. BINGO! They were all loose. I torqued them to spec, re-assembled, reset tps and IAC and.......she purrs better than the day I brought her home. I see and intake gasket in my future.

To Oldalaskaman, an extra shout out for reminding me to use logic and re-trace my steps. Sometimes we are our own worst enemy.



Thanks again all!
Reply
Old Jul 5, 2011 | 09:43 PM
  #27  
oldalaskaman's Avatar
oldalaskaman
Le Mans Master
10 Year Member
 
Joined: Aug 2010
Posts: 9,272
Likes: 17
Default

you are very welcome, I have been there and done that.
Reply
Old Jul 5, 2011 | 09:50 PM
  #28  
Gear Jammer's Avatar
Gear Jammer
Racer
15 Year Member
Active Streak: 30 Days
Active Streak: 60 Days
Active Streak: 90 Days
 
Joined: Jul 2007
Posts: 379
Likes: 12
From: Huntsvegas AL
Default


Glad you resolved this; I need to do the same to my 91. Roughly a year ago I pulled the plenum to replace the EGR. Now I have intermittment idle issues - I didnt think to check the intake manifold bolts while the plenum & runners were removed. I bet mine are loose too.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-1

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-2

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-3

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-4

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-5

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-6

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-7

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-8

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
story-9

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski
Old Jul 6, 2011 | 07:15 AM
  #29  
stoydido's Avatar
stoydido
Instructor
 
Joined: Jun 2011
Posts: 182
Likes: 0
From: Bowling Green Ky
Default

Originally Posted by Gear Jammer

Glad you resolved this; I need to do the same to my 91. Roughly a year ago I pulled the plenum to replace the EGR. Now I have intermittment idle issues - I didnt think to check the intake manifold bolts while the plenum & runners were removed. I bet mine are loose too.
did that, too, checked intake at suggestion of another forum comment -who'da'thunkit? the inside bolts were a wrist-turn loose, or tight, never had any idle issues. I tightened all of them, see no reason to replace gaskets. it's the torque that seals it.

jc
Reply
Old Jul 6, 2011 | 11:17 AM
  #30  
oldalaskaman's Avatar
oldalaskaman
Le Mans Master
10 Year Member
 
Joined: Aug 2010
Posts: 9,272
Likes: 17
Default

Originally Posted by stoydido
did that, too, checked intake at suggestion of another forum comment -who'da'thunkit? the inside bolts were a wrist-turn loose, or tight, never had any idle issues. I tightened all of them, see no reason to replace gaskets. it's the torque that seals it.

jc
if they're not leaking, dont fix em
Reply




All times are GMT -4. The time now is 07:43 AM.

story-0
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-1
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-2
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-3
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-4
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-5
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-6
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-7
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-8
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE
story-9
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE