ok i have been having some problems with my 94 z28 this past week, first of all the radiator hose popped off when i was going down the road and i sucked some coolant up threw my cold air intake. car running like **** and misfiring on 2,4,6,8. pulled a code yesterday for the o2 sensor, was going to replace today. anyways. Today when i went to go to work,i got in the car and started it and as soon as it started up it died, and wont start again. I pulled a wire off of one of my plugs and put a old plug in it and there is no spark to the plugs. wtf. Now i have been reading up on this for 4 hours now. Everyone is saying bad opti, bad coil, bad ICM. idk, im not good with electrical. I disconnected the battery and let it sit for about a half hour and reconnected it and tryed to start it and the battery was dead, so i charged it up but still no start. now here is a list of what i have replaced in the last couple months.

Brand New Opti
water pump
radiator
starter
mass air flow sensor
plugs + wires
coolant temp sensor
coolant temp switch
(thats about all i have done to the motor)

please help, my friend owns a LT1 shop and he is going to bring a couple coils and ICM's over later tonight, but i kinda wanna get ahead of things now. Please help. if there is anything you need to know ask and ill tell you. Thanks so much

 

You'll have better luck when posting your question in the proper section. This is LS1 based engine tech.

 

i had it in another location and everyone told me to come here, thats why my problem is here now.

 

You have an LT-1 you need to put this there and you will get some answers. Or ping a mod and have them move it for you.

 

Nice looking car, wrong forum though From the sounds of it i would guess the opti is done. You can test each coil with a multimeter to see if your getting anything.

 

Yup wrong section for sure however I did not see am ICM on your list of parts..

 

Moving this.

 

Check the short harness that plugs into the opti..it may have some corrosion in there.

If you got coolant on your new opti you might need a new cap/rotor

Do you pull the codes from the computer? Some don't set the Serveice Engine Soon light...

 

Here is what you can do to check your ignition system out.

Disconnect the ICM connector. Leave coil connected.
Turn key to ON.
Check for dc voltage with a digital meter at harness terminal "A" to ground and and also "D" to ground. Note: Use a high impedance meter (at least 10 megohm) to protect the PCM.
Result should be 10v dc or more on both terminals. If you get no voltage, use the diagram and chase back toward the coil and the ignition fuse. Power for the ICM comes from the ignition fuse and through the coil, so any of that could be bad.
If you have good voltage, switch the meter to ac scale and connect test leads to terminal "B" and to ground. Observe meter while cranking the engine. You should see between 1 and 4 volts ac (those are the pulses that trigger the coil to fire).
If you don't see the proper ac voltage the problem could be the optispark, the harness to the optispark, the PCM (not common) or any of the wiring in between. Visually inspect all the connections you can get to for poor contact or corrosion.

At the end of the optispark harness (disconnected from the opti) with the key ON, you should see:

A = ~5vdc
B = ~5vdc
C = 12vdc or system voltage
D = ~0 - 0.2 ohms ground


The easiest way to check that your opti and PCM and harness is good
Is to have ac voltage going to your ECM on terminal B
Here is the diagram
http://shbox.com/1/95_ign_system_schematic.jpg

 

try this, wiggle your connector going to your ICM, mine wasnt getting spark after replacing the whole damn ignition system, ICM,opti coil, ect ect..

wiggled it while someone was cranking it and it fired right up.... and i bought a new icm for 103.79 from rock auto.com to try and fix it and turned out i didnt need it, man was i ticked,

if that doesnt help, PM me and ill helpout anyway i can... but i dont think your opti went, to be honest water doesnt kill them as easy as everyone thinks,

 

i have almost the same problem but mine had oil inside my optispark anybody knows how it got inside the opti

 

https://www.camaroz28.com/forums/lt1...e-help-846807/

No need to post a topic multiple times. Posting it once, generally produces the best results.