I had my car running at about 3000 rpm and it shut off... I have grounded a spark plug to see if it was sparking because i could smell fuel.

I replaced the opti spark checked to make sure i was getting the right ac voltage which is about 2.2, still no fire. I rechecked all 4 wires going into the icm to make sure im getting at least 10 volts and the ground.

I replaced the icm as well as the coil, still no fire. I replaced the wire that goes from the coil to optispark, still no fire.

Is there anything else that i can check or is there anything anyone can think of that i have missed i would really like to get this thing running asap i appreciate any help.

 

Have you scanned it for codes?

Did you check both ends of the short Opti harness to insure there was no corrosion or damage to the pins?

 

I bought a new short opti harness... I have not had it scanned because i have not found a scanner that it will work on. the computer is also a new tune from pcm for less. i put in the factory computer just to check for spark and still nothing. Also i am using a brand new ngk iridium tr55 plug and a brand new battery.

 

Exactly where did you measure 2.2V AC?

 

At the icm was where i got the 2.2 v ac and i just got back inside from putting on a third distributor since the problem happened. It has about the same ac current at the icm about 2.2- 2.4 ish. The ground wire was a little strange on the icm connector it was only reading at 9.75v so i ran a ground wire directly to icm connector and made sure it read 12v. Will it make any difference if the ground at the icm is straight to a ground on the body or does it need to be the wire coming off the harness? still no go on spark.

 

Maybe your wires are bad? is that a possibility?

 

Dumb question...have you checked the fuses?

 

The grounds in the harness are dedicated grounds. I have a few issues with your post that I can help with if you can clear them up for me The biggest is the ground should have no voltage.

You have ABCD pins in your ICM connector. We will look at them as such from left to right ABCD....forget any schematic you have in front of you just go by this and you will see what I am saying lol. Take pin A (black ground wire) turn your meter to ohms, if you have an audible tone for continuity thats good too. Ring it out to make sure it is good. You have just verified ground! Pins B C should both have 10+volts DC(it should be whatever your battery charge is but 10 is acceptable). Pin D, the solid white is the one with AC Voltage. It will toggle from 0-5v's. Depending on your meter will be the value that you see or dont see. I recommend using the ground that is in that connector to test everything else in that connector, because the sensor does. I know there is a redundant ground because the coil/Icm bracket is grounded, but the path of least resistance in theory is the ground in the connector. Just a few pennies of mine to you. If you wnat to ring out the white wire (AC voltage) it is pin 12a on your PCM. It goes from that connector straight back to the PCM. The AC pulse is commanded by the opti via low and high resolution pulses, the Electronic Spark Timer uses those pulses to determine when to send the volatge to the ICM, which in turn sends it to the coil to make it fire.

To sum that up:

1. Is there power to the ICM should be 2 wires with 10+ dc volts to ground.
2. Is the opti sending the signals to the computer?
3. Is the computer generating the AC volatge to fire the coil?

 

the opti is sending signals to the computer.

On the icm the 2 wires do have 12v dc when i ground to chassis. If i ground those 2 12v dc wires using the ground on the icm i am getting 9.75v dc. I traced this wire back to the computer it does not tie into any ground wires it goes into the black connector Pin 5 which is ignition control. I have checked several grounds throughout the harness to make sure i get 12v dc on those 2 wires and they do.

What feeds the ground for the ignition control on the computer... I am certain this is where my problem lies but i have no idea where to look for problems once the wire goes into the computer.

ALSO I HAVE TESTED 3 DIFFFERENT COMPUTERS.

 

Are you positive the opti was installed correctly ?

 

Bails098. The ground in that harness is computer controlled from what I have gathered.

It works like this:

You have two constant hots with no ground, which equals no circuit. When the opti sends the signals to the puter the puter then deciphers it and pulls the contact in for the ground effectively closing the circuit, or making it complete. There is a driver built into the puter that does this it is called the ETS driver. As far as it being pin 5, I was talking about the white wire. I highly doubt you found 3 bad PCM's. If the wire is good, the PCM is good, the ICM is good, then your problem is in the opti.
9.75 volts is good enough due to the resistance. The white wire is the one you want to check out
I am chaisng a similar problem only mine fires and then runs and quits once it gets hot and is sending 0 volts AC on the white wire.

 

yes the opti is right and ive tried 3

 

I have also had 3 different opti's on the car as well since the problem started 2 of which are brand new.

 

what brand opti?

 

I had a msd, then i got one off ebay dont know the brand just a cheap one and i got one from chandler motorsports.

I put in another icm incase i got a bad one and still nothing. Im going to try the same with a coil.
If the coil does not work im going to get an opti from a guy who had it running on his car recently.