1994 Z28 Lt1.i Put New Head Gaskets On And Had The Heads Redone.put The Car All Back Together And No Spark.checked All The Wires And They Are All Hooked Up.put A New Coil On And Still Nothing So I Disconnected The Wire From The Opti And Grabed The Wire And No Shock [very Desperate].the Car Will Turn Over But Will Not Fire.i Hooked A Scanner Up To It And It Is Saying That It Passes And No Codes Come Up.im Lost And Need Help.i Have Put Alot Of Time And Money In This Car And Would Like To Keep It But Getting Very Frustrated.after I Put The Car Back Together I Tried To Start It And It Ran For About 5 Seconds And Died.i Had Someone Adjust The Valves For Me And I Was Wondering If He Did It Wrong Would There Be No Spark?what Could It Be If I Have No Spark From The Coil?thanks For Any Help

 

I personally, would highly recommend going here http://shbox.com/page/index.html. Shoebox's site has many different ignition tests you can run and it will help you narrow your problem down. I have visited his site as many others here have as well and it is a great reference for us LT1 guys Good luck, to me it kind of sounds like your coil or module, but there are other known culprits.......

 

Just start troubleshooting step by step... If you've got no spark, I'd look at your coil and/or opti. When removing the coil, the braided ground wires are succeptable to breaking, so make sure that it's grounded properly.

You can check if the coil/opti are functioning if you've got a digital voltemer. If not, I would buy one, or if you've got a friend with an LT1, you could borrow his/her coil, and try it. They're quick to swap.

Make sure to double check all your wiring too!

 

I Change The Coil Already And All The Wiring Is Hooked Up.

 

You can check if your ECM is sending power to your opti with a voltometer. I don't have the instructions in front of me on which wires to check, but I do know that the 4-prong opti plug can be tested for power. You should try here.

My haynes manual has the info. If you don't have the manual, let me know, I can dig mine up, and find out for ya.

 

possibly the opti was put on wrong at the dowel pin on the cam? ?

 

First of all - turn your caps lock key OFF. The forum software converts
an all-caps-posting to word-caps, which is just as difficult to read.

Secondly, you've answered your own question. You say you grabbed the
coil wire (well, you didnt say it specifically, so I'm assuming it) and you
did not get shocked (which is a pretty stupid way to check the coil and
spark plug wires).

There are checks you can perform on the ignition system - you need
to perform those to see where the issue lies.

http://shbox.com/1/4th_gen_tech1.html