On thursday my trusty 'ol 1996 z28 seemed to be missing or running rough, (it WAS -10 deg) after I got it home I popped the hood and noticed I was hearing what sounded like a small air leak on the right hand side of the manifold. With the engine still running I popped the PCV to see if the hoses leading to it had cracked. (they hadn't) however, the car stumbled and died and won't restart.
I left it for two days until the weather warmed up some and still cannot get her to fire.
I am seeing gas at the fuel rail and the fuel pump is energizing.

So today I ran to o'reilley and borrowed an autoxray code scanner.
It returns with these codes, I want to know what is causing the no-start first and work back from there..
p0412 Secondary air injection system switching valve a circuit malfunction (doesn't seem likely to me)
p0141 o2 sensor heater circuit malfunction (bank 1 sensor 2)
p0100 Mass or volume air flow circuit malfunction
p1351 ICM control module circuit high voltage

The car had never quit or stumbled and the only real symptoms presented previously was that the vehicle would have a slightly 'gassy' smell after idling for 10 mins while warming in the am and a slightly different sound from the exhaust, I would have thought it could be mis-firing but the engine seemed to run smoothly upon inspection.
The p1351 would seem the most likely candidate to me but previously when i have had opti problems they never presented like this!!
Since the exhaust note sounded different than typical this makes me wonder about the cats, will a plugged cat cause no fire??
can anyone help me?
Thanks

 

I'm thinking it's the p1351 also. I've heard that it can cause a no start condition. Check the connections on the ICM for corrosion and see if you have power to the ICM. Heat soak maybe?

 

P0100 is for a static reading on the MAF sensor. Unplug it and see if it starts. Check for 12V (key on) between the pink wire in the harness connector and the black/white ground wire.

P1351 inidcates an open circuit on the white wire from the PCM to the IC Module. That's the signal from the PCM that tells the ICM to fire the coil. Check per Shoebox's procedure:

http://shbox.com/1/4th_gen_tech2.html#opti_test

P0412 indicates a problem with the AIR pump solenoid, usually due to a blown fuse. Won't prevent it from starting.

P0141 determines that the B1S2 sensor isn't heating up fast enough, and assumes there's a problem on the power supply, or the heater in the sensor is damaged. The PCM measures the time for the sensor to reach operating temperature, and if it was cold enough, that could cause the problem. This will not keep the engine from starting and will not affect the way it runs.

 

Doubting Heat soak is currently a factor as the high temperature during the time this has been occurring has been 0 deg F outside the garage where my car is 'resting', finally today we are a bit above freezing.
Thanks!

 

p0100 Unplugged MAF sensor and no change =(

checked U/H fuse at #11 and it is intact =(
453 Red/Black has 5.0V to ground
632 Pink/black has .02V to ground?
430 ppl/white (terminal b) .o4v ac to ground
DOH! tested the wrong connector! this was PCM to opti duh!

Glad to know that p0412 and p0141 cannot be the reason It will not start.

I guess it's time to break out the multimeter and start trying to follow some wiring around before it gets too dark to do properly.
Damnit it if only this engine didn't have that damn optispark but at least i haven't had to replace it in the past four years (a record!!)
Thank you!

 

Please excuse the FILTHY engine compartment
My ICM connector and wire colors are all different from the shoebox site =(


12v to the coil


I am getting 12V DC on the OUTSIDE pins??


but NO voltage to the center pins???




still no fire
also, while it WAS still running i checked the plug wires and had no arcing/sparking

Where does this leave me now???
Thanks so much to all that reply!

 

Bad Optispark?

 

Have you ruled out the fuel pump?

 

don't think its fuel related.

 

did u check for spark after it died?

I guess try at coil first. and if its there check wires.

 

Are you comparing it to the colors shown in the correct 96/97 schematic:

http://shbox.com/1/1996_ec_03_ign_system.jpg

I see:

1848 Dk Green
450 Black
423 White
239 Pink

Doesn't that match your photo?

When you checked the voltage to the white wire, did you set the meter to AC volts?

 

My apologies; yes I did measure AC on white, I got a reading of 2.0 Vac to ground but didn't take a shot of it thru the windshield.
I also Ohm'd white to ground and got 215 Ohms resistance.

Sorry for the incomplete data set and THANKS SO MUCH to all who have taken their time to assist me.
Cheers
Has been a one man testing show so far but will recruit a key turner tomorrow =)

 

Take the wire off from the optispark that comes from the icm and crank it. If there's no spark then its your icm.

 

There is no wire "from the optispark that comes from the icm". Do you mean the wire (dark green) that goes from the ICM to the coil? Or do you mean pull the high voltage wire that goes from the coil to the Opti.

 

How much resistance should i be seeing from BLACK-450 to ground?
I am seeing almost 40 ohms and by the schematic it looks like this should be direct to ground is it possible this is an issue?
And should i be trying to test the ICM next?