LT1-LT4 Modifications 1993-97 Gen II Small Block V8

do i have a bad opti???

Thread Tools
 
Search this Thread
 
Old May 18, 2007 | 12:54 PM
  #1  
lt1 power's Avatar
Thread Starter
Staging Lane
 
Joined: Apr 2007
Posts: 87
Likes: 0
From: Mechanicsville, Va
Default do i have a bad opti???

lately my 94 z28 has started to act up on me, i think the opti is going bad, but want to make sure. the car has been surging alot lately, the rpms will start jumping back and forth while driving. it also has a rough idle and poor performance once car gets warmed up ,sometimes it doesn't start right up like it should, almost seems like the injectors are cutting on and off. repaced injectors still surges and runs the same as before. it is a low 12 sec car and i took it to the track the other day, it ran a 13.4 @100. something is obviously wrong with the car, it is tuned, i am thinking it is either a bad opti or maybe computer related no codes or check engine light. please help what is wrong with my car??
Reply
Old May 18, 2007 | 01:04 PM
  #2  
Captainofiron's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: Apr 2006
Posts: 1,687
Likes: 0
From: New Mexico
Default

You arent getting any codes?
to me sounds like a coil or wire problem,

Usually the opti throws a high resistance or low resistance timing reference code. If you arent getting one of those I would be cautious about throwing money at a new opti
Reply
Old May 18, 2007 | 09:37 PM
  #3  
purplefirehawk95's Avatar
Teching In
 
Joined: Nov 2005
Posts: 42
Likes: 0
From: Michigan
Default

Another thing you might want to check is your fuel pump. Do you have a fuel pressure gauge? You should be some where around 41-47psi I beleave.
Reply
Old May 19, 2007 | 12:05 PM
  #4  
lt1 power's Avatar
Thread Starter
Staging Lane
 
Joined: Apr 2007
Posts: 87
Likes: 0
From: Mechanicsville, Va
Default

i checked the fuel pressure it was 41 with the key on and 38 started at idle.
Reply
Old May 19, 2007 | 12:25 PM
  #5  
ecniv's Avatar
Staging Lane
iTrader: (1)
 
Joined: Jul 2005
Posts: 93
Likes: 0
Default

A bad opti won't always throw a code. I do agree that it sounds like a weak coil - you can do resistance checks on the coil to give you an idea of it's health.
Courtesy of Shoebox:



You may also want to look into your ICM. Does it behave when the car is cold and get worse as it warms up?

Also, open the hood at night and look for arcing and sparking from the plug wires - you may just have a bad wire (as stated above) that's causing a random misfire.
Reply
Old May 19, 2007 | 03:59 PM
  #6  
lt1 power's Avatar
Thread Starter
Staging Lane
 
Joined: Apr 2007
Posts: 87
Likes: 0
From: Mechanicsville, Va
Default

plugs and wires are good and just replaced the coil car is still having the same problem.running rough surging through all rpms, lack of power. i also noticed when pulling the plugs the drivers side plugs were very lean and the pass side was stoich, what could cause one side to be getting more fuel than the other?
Reply
Old May 19, 2007 | 04:09 PM
  #7  
ecniv's Avatar
Staging Lane
iTrader: (1)
 
Joined: Jul 2005
Posts: 93
Likes: 0
Default

02 sensor
Reply
Old May 19, 2007 | 07:19 PM
  #8  
lt1 power's Avatar
Thread Starter
Staging Lane
 
Joined: Apr 2007
Posts: 87
Likes: 0
From: Mechanicsville, Va
Default

could a bad o2 sensor cause the car to surge and have a lack of power also? hopefully this is all that the cars problem is. i will check the o2 sensor and see if it's working.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo




All times are GMT -5. The time now is 08:59 AM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE