I'm in the same boat as other 93's. ECT is new and good verified by the XFI box, aftermarket ignition box is good verified by the LED light AND no fault codes stored or showing during crank. Swapped back to stock ignition configuration and still no spark. Change coil and ICM w/ same results. No fire from coil or from coil goint to opti and tested w/ a test probe light. If I smack the coil SOMETIMES it'll give off a light blue spark but it's clearly not arching or jumping to the test probe. Check for spark at the plug and no spark whatsoever. Fuel pressure is steady @ 43.5psi, have enough volts at battery. I'm bout done w/ this bastard as she ran perfectly before I did a little maintenance to the car.

All I've done thus far was reroute and rewire my ignition wires as they were in the way of my pullies, got rid of the evac canister, speed inc alt relocation and battery relocation. That's pretty much it.

Is it possible the VATS has gone bad and how would I test it? Any other ideas? The opti is new and I had a spare good one laying around and got the same results...just in case anyone was wondering.

Thanks!

 

Sounds like a bad coil, but it's new. Have you checked the white wire on your icm? also check the ground wire in the loop of wires in the icm bundle of wires. What about your wires going from the icm to the coil and the other wires going to the coil? Most I have seen the wires on the coil are at a 90 and break loose right next to the conector. I would probe the known hot wires and wiggle to see if you can get them to short or become open. Also are your injectors firing? security light on?

 

Haven't checked the white wire but in the process of doing it now. All the other wires check out fine but I'll go over them again to see about that 90 and the break next to the connector. No SES light, only light I have is the brake light and check gauge light. Those were both on while the car was running as that's when I did the line lock lines only.

 

Everything checked out w/in normal parameters. WTH?! No codes of any and I even did the jumper just for giggles and nothing. Ignition switch maybe? I don't figure this out, I'll be parting out a 5yr old motor w/ less than 1100 miles on it along w/ the F1 (same mileage), fuel system (same mileage) and the XFI. I've just about had it.

 

When you checked the white wire, did you get a variable voltage as the engine cranked?

Courtesy of Shoebox

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

Have you checked the resistance of the coil:

http://shbox.com/1/coil_testing.jpg

 

I would first calm down. When you said you changed out the opti, did you open them up and inspect the cap and rotor. Now back trac in reverse of every thing you did from finish to start. It's probly something really dumb that you over looked.

 

Fred,

Got voltage as the engine cranked, can't remember exactly what it was number wise but I've got a buddy coming over to go over what I done. 2nd pair of eyes may help.

Pizzi, I didn't swap the opti out, it's a new opti on and had a function spare laying around. Just used my harness to connect to it and used a seperate plug wire and plug to see if I got the same results. It's got to be something stupid but I haven't the slightest idea what.

 

Confirmed opti even though there are no codes stored. I'm assuming that this is possible. 1st failure in 15yrs and couldn't have come at a worse time. Ditching altogether for COP's.

 

What failed on the Opti, and how did you confirm that was the cause?

 

Fred,

We got power from the ignition box to the coil, but none to the ICM. Got pwr from the factory harness to the coil and had pwr to the ICM.

The battery tested on 10v through the XFI and I know it needs at least 12v. Threw the truck battery on for giggles and read 14.4 and still no start so I could rule out right there the factory PCM and XFI are getting enough power.

Connected the test lead went to ac scale and didn't see any reading . The harness is fine. I don't know where else to look beside the ignition switch which I'm trying to figure out how to test now. I'll throw another opti on and see what it does just to be sure, what can it hurt at this point? What I don't get is it still didn't throw a single fault code.

 

Just to be clear... I'm not challenging your conclusions, just making sure I understand the process you used for future reference, particularly with the fact you are using the XFI.

If you don't have a pulse signal on the white wire to the ICM, that's a good indication that the Opti is not producing the low res pulse signal. If you had a stock PCM you would get a trouble code for that. With your XFI, is there a diagnostic for the cam reference signal? With my MoTeC, being fed directly from the Opti, there is a trouble code for loss of cam reference signal. And I also run the stock PCM for the speedo, idle air control and fan control, so the problem with the low res pulse would show up there as well.

Always trying to learn more about the LT1.

 

Fred, I'm not taking offense in the slightest. You are one of the old guard and your wisdom is respected. I still use the factory ecu to pwr the pumps and it's also piggybacked to the XFI for when there is a SES the dash will light up also. XFI will store the code and I can read it that way or go old school and do the jumper trick w/ the paper clip. Either way I still do not get any code. Keyed on, SES will light then go off, proceed to start and no SES or fault code shows up. I'm not running a crank trigger wheel so all reference comes from the opti to the XFI/ECU etc.

No signal to white wire either. I'm pretty sure the opti shattered now when I think about it. Had a few dyno runs last yr and one pull she got up to 6K and the call lurched forward like someone took the wind out of it...more or less fell on its face. Next pull 6600 no problem. EVERY once in blue moon I'd get that same symptom on the street but it's so far spaced apart I never put the 2 together. Like I said, I've only got 1K if that on the opti. Clearly it doesn't matter though.

 

Loose rotor?

 

I'll know later this wk when I pull it and post a pic of what's inside. Could very well be it though.

 

Had a similar instance and turned out to be my ignition switch on the steering column burnt out like a tone of other lt1s out there. I would get the intermittent to no spark symptons and did all the testing and came out with nothing and then turned to the ignition switch and it was burnt up and would only get connecting when it wanted to. Worth a try and hopefully one less thing ignition related to deal with or so we hope...