1996 Corvette changed coil and controller. now won't start - Page 2 - CorvetteForum - Chevrolet Corvette Forum Discussion


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

1996 Corvette changed coil and controller. now won't start

Reply
 
 
 
Thread Tools Search this Thread
Old 05-16-2018, 09:23 PM   #21  
MatthewMiller
CF Senior Member
 
MatthewMiller's Avatar
 
Member Since: Aug 2015
Location: St. Charles MO
Posts: 1,283
Thanked 152 Times in 129 Posts
Default

Quote:
Originally Posted by Southern Boy View Post
Thanks to an idea here, I was able to put a spark tester on where I could see it while cranking over the engine. No spark! what could I have done by changing the coil and ICM? The original ICM and coil are back on the car so it isn't a matter of defective new parts.
Time to start tracing the ignition circuit backwards. Do you have spark at the output of the coil (test the same way)? If not, are you getting signal to the coil from the ICM? If so, is the ICM getting its signal?

Here is a useful diagnostic procedure for some of this stuff: http://easyautodiagnostics.com/gm/4....test-the-icm-1.

Last edited by MatthewMiller; 05-16-2018 at 09:31 PM.
MatthewMiller is offline   Reply With Quote
Old 05-16-2018, 10:25 PM   #22  
belairbrian
CF Senior Member
 
belairbrian's Avatar
 
Member Since: Oct 2016
Location: Central Alabama
Posts: 1,042
Thanked 110 Times in 99 Posts
Default

Just another approach to checking spark that I've used. It works for the coil wire as well.
I use an inductive timing light like a noid light. Just clamp to any wire and hold it while starting the car. It will flash if there is spark.

Coil wire will flash so fast it will look solid but it still tells you the light is seeing spark.
belairbrian is offline   Reply With Quote
The Following User Says Thank You to belairbrian For This Useful Post:
Southern Boy (05-17-2018)
Old 05-16-2018, 10:52 PM   #23  
Southern Boy
Junior Member
Thread Starter
 
Member Since: May 2018
Posts: 10
Thanked 0 Times in 0 Posts
Default

Quote:
Originally Posted by FAUEE View Post
You need to follow shbox lt1 no start guide.

From memory, to get spark the icm needs a signal from the ecm to send the trigger to the coil. Then the coil woll fore, and send spark thru the opti. So I would check if you'e getting signal to the icm, and then from the icm to the coil.

It's an old car, you may have broken a wore during the install.
FAUEE, my thanks to you and to all the helpful members of this forum who responded to my request for help! It was exactly what you suggested - the wiring is old and I must of broken a wire when doing the install. After fixing, she instantly fired up and ran. I have decided to live with a uneven idle for now rather than going through this issue again. Thanks again to all!
Southern Boy is offline   Reply With Quote
Old 05-16-2018, 11:59 PM   #24  
MatthewMiller
CF Senior Member
 
MatthewMiller's Avatar
 
Member Since: Aug 2015
Location: St. Charles MO
Posts: 1,283
Thanked 152 Times in 129 Posts
Default

I'm very glad you solved the biggest issue! It's an easy problem to have on a car as old as ours.
MatthewMiller is offline   Reply With Quote
The Following User Says Thank You to MatthewMiller For This Useful Post:
Southern Boy (05-17-2018)
Old 05-17-2018, 08:46 PM   #25  
fake
CF Senior Member
 
Member Since: Jan 2004
Location: Glastonbury CT
Posts: 401
Thanked 7 Times in 7 Posts
Default

Ring out the wires you removed. You most likely have a break in the circuit!
fake is offline   Reply With Quote
Old 05-17-2018, 11:05 PM   #26  
Southern Boy
Junior Member
Thread Starter
 
Member Since: May 2018
Posts: 10
Thanked 0 Times in 0 Posts
Default

Quote:
Originally Posted by fake View Post
Ring out the wires you removed. You most likely have a break in the circuit!
Fake, forgive me, I'm just a farmer. What does ring out the wires mean?
Southern Boy is offline   Reply With Quote
Old 05-17-2018, 11:09 PM   #27  
Southern Boy
Junior Member
Thread Starter
 
Member Since: May 2018
Posts: 10
Thanked 0 Times in 0 Posts
Default

Quote:
Originally Posted by belairbrian View Post
Just another approach to checking spark that I've used. It works for the coil wire as well.
I use an inductive timing light like a noid light. Just clamp to any wire and hold it while starting the car. It will flash if there is spark.

Coil wire will flash so fast it will look solid but it still tells you the light is seeing spark.
belairbrian, that is a great idea and certainly helpful for someone like me having to crank over the engine by themselves while simultaneously checking for a spark. Thanks!
Southern Boy is offline   Reply With Quote
Go Back   CorvetteForum - Chevrolet Corvette Forum Discussion >
Reload this Page
  • 1996 Corvette changed coil and controller. now won't start
  •  
     
    Reply

    Related Topics
    Thread Thread Starter Forum Replies Last Post
    1985 Auto won't start. Ideas? rick I M C4 General Discussion 55 07-22-2017 05:43 PM
    Advice please 65 bb wont start after rain 1Cerberus4u C1 & C2 Corvettes 23 06-25-2017 09:51 PM
    LT1 coil failure causes? Look for? 40flier C4 Tech/Performance 5 02-06-2017 08:43 AM
    1995 Wont Start After Water Pump Leak 8valve C4 Tech/Performance 14 06-30-2016 03:39 PM
    Chevy related but not a corvette, help scrappy76 C3 Tech/Performance 12 04-27-2016 05:21 AM


    Thread Tools Search this Thread
    Search this Thread:

    Click for Advanced Search

    Posting Rules
    You may not post new threads
    You may not post replies
    You may not post attachments
    You may not edit your posts

    BB code is On
    Smilies are On
    [IMG] code is On
    HTML code is Off
    Trackbacks are Off
    Pingbacks are Off
    Refbacks are Off

    Forum Jump

    Sponsored Ads
    Vendor Directory

    All times are GMT -4. The time now is 07:15 PM.


    We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
     
    • Ask a Question
      Get answers from community experts
    Question Title:
    Description:
    Your question will be posted in: