C4 General Discussion General C4 Corvette Discussion not covered in Tech

HELP Needed-C4 - ENGINE

Thread Tools
 
Search this Thread
 
Old Jul 16, 2006 | 11:40 AM
  #1  
vinnies87's Avatar
vinnies87
Thread Starter
Le Mans Master
 
Joined: Aug 2003
Posts: 9,884
Likes: 3
From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
Default HELP Needed-C4 - ENGINE : FIXED 4pm

Guys, Need some help here. (87/L98/Stock)

She starts right up, runs high idle, then slowly chokes out and dies. You can give her gas, and she will continue to run, with constant gas, but leave off the throttle and she chokes out and dies.

Pressure : 43psi @ rails and holds for 1hr+
Startup: Fires right up, no hesitation on startup
Battery: 12.2v costant
Codes: No error codes and no codes during scan while running.
Vacume Lines: all lines check and connected, no leaks, did leak testing

Any help would be appreciated.
thanks
vinnies87

Last edited by vinnies87; Jul 16, 2006 at 11:23 PM.
Reply
Old Jul 16, 2006 | 11:51 AM
  #2  
Fast Cop's Avatar
Fast Cop
Melting Slicks
10 Year Member
 
Joined: Feb 2006
Posts: 2,938
Likes: 62
From: Columbia SC
Default

The first thing I would check is the in line fuel filter and then work from their.
Reply
Old Jul 16, 2006 | 12:31 PM
  #3  
vinnies87's Avatar
vinnies87
Thread Starter
Le Mans Master
 
Joined: Aug 2003
Posts: 9,884
Likes: 3
From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
Default

Originally Posted by Fast Cop
The first thing I would check is the in line fuel filter and then work from their.
Thanks, but if i had a fuel problem, i would not hold 42psi at the rails on startup, again, it could be a constant fuel issue, to think about it.
Reply
Old Jul 16, 2006 | 01:55 PM
  #4  
corvetteronw's Avatar
corvetteronw
Race Director
Supporting Lifetime
20 Year Member
Veteran: Army
St. Jude 10 Year Donor
Liked
 
Joined: Feb 2003
Posts: 16,475
Likes: 270
From: Kingman AZ
Cruise-In VII Veteran
Cruise-In VIII
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16
Default

On the 86 I used to have the cat plugged up and caused the same problem. I have heard that you can check for a plugged cat with a temp/pyro gun. It the temp of the pipe coming out of the cat is much less than the temp of the pipe in front of the cat then you have found the problem.
Reply
Old Jul 16, 2006 | 01:58 PM
  #5  
86Pacecar's Avatar
86Pacecar
Burning Brakes
20 Year Member
Conversation Starter
All Eyes On Me
 
Joined: Mar 2003
Posts: 1,174
Likes: 6
From: NW MN
Default

Check your IAC, sounds like it's not functioning.
Reply
Old Jul 16, 2006 | 02:15 PM
  #6  
vinnies87's Avatar
vinnies87
Thread Starter
Le Mans Master
 
Joined: Aug 2003
Posts: 9,884
Likes: 3
From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
Default

Originally Posted by 86Pacecar
Check your IAC, sounds like it's not functioning.
Replaced with new IAC and set per Helms spec. Havd additional post in Tech section with diag from last 2 tests, same title
Reply
Old Jul 16, 2006 | 05:13 PM
  #7  
AILERON's Avatar
AILERON
Burning Brakes
 
Joined: Apr 2005
Posts: 784
Likes: 0
Default

Sorry to hear you're having problems, Vinnie.

I had a very similar experience with my 90 and it turned out all three cats were plugged up.

Do the pyrometer check that's been suggested. It should tell you a lot about what you're up against.

Good luck.
Reply
Old Jul 16, 2006 | 05:30 PM
  #8  
RRT vette's Avatar
RRT vette
Le Mans Master
15 Year Member
 
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Default

Originally Posted by corvetteronw
On the 86 I used to have the cat plugged up and caused the same problem. I have heard that you can check for a plugged cat with a temp/pyro gun. It the temp of the pipe coming out of the cat is much less than the temp of the pipe in front of the cat then you have found the problem.
This is a good/reasonable suggestion. A semi plug cat or precats would cause this. You can check the temp as suggested or hit them with a rubber hammer and listen for rattles. Are they stock? Also check the TPS voltage since you say you can give it trottle to make it run. The throttle plate position changes the voltage, as you know.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

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

 Joe Kucinski
story-1

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

 Verdad Gallardo
story-2

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-3

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

 Michael S. Palmer
story-4

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

 Joe Kucinski
story-5

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

 Michael S. Palmer
story-6

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

 Joe Kucinski
story-7

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski
story-8

5 MOST and 5 LEAST Popular Corvette Model Years in History!

 Joe Kucinski
story-9

2027 Corvette Buyer's Guide: Everything You Need to Know!

 Joe Kucinski
Old Jul 16, 2006 | 11:22 PM
  #9  
vinnies87's Avatar
vinnies87
Thread Starter
Le Mans Master
 
Joined: Aug 2003
Posts: 9,884
Likes: 3
From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
Default

Posted update in Tech section, Turned out to be : Ready:
Something in the ECM got stuck: Removed ECM, replaced with backup good ECM and Stock Chip, Installed and she fired up, ran kinda ruff, Removed and replaced with current ECM and PCM Chip, Installed and she fired right up again. Then Did the complete reset of : IAC, Timing, TPS and buttoned her up... No issues. Gonna put this on the Check List.
Reply

Get notified of new replies

To HELP Needed-C4 - ENGINE





All times are GMT -4. The time now is 10:41 AM.

story-0
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-1
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-2
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-3
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-4
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-5
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-6
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-7
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
story-8
5 MOST and 5 LEAST Popular Corvette Model Years in History!

Slideshow: 5 most and least popular Corvette model years.

By Joe Kucinski | 2026-04-08 13:25:01


VIEW MORE
story-9
2027 Corvette Buyer's Guide: Everything You Need to Know!

Slideshow: 2027 Corvette buyer's guide

By Joe Kucinski | 2026-04-17 16:41:08


VIEW MORE