Injectors still not grounding out...

I've about had it. Thanks to anyone who can offer advice:

*1994 Trans Am GT M6. New solid-roller 383ci setup. Never started.*

-No DTC codes / No SES light / No SECURITY (VATS) light
-Engine cranks over just fine
-Has proper fuel pressure (~44psi)
-Has spark @ plugs
-Fuel injector circuit has power all the way up to the PCM connector
-When I manually ground out the injector circuits, each injector fires, and the engine kicks (like it wants to fire up) when I next turn the key -- until the small amount of fuel I manually injected goes away.
-Injector DC is 0% while cranking.
-I've used 3 different PCM's. I just put in a new tuned PCM from Bryan Herter to completely take myself out of the equation.
-On my last tune (which I uploaded), I disabled VATS to no avail, albeit the PCM fried when I tried to upload a second time, so the first tune was questionable.
-Only disconnected electrical connectors are for the low oil sensor and EGR solenoid (disabled). Everything else is in and readings look normal.


So, the only thing left, in my mind, would be a screwy mysterious Optispark signal, or perhaps some VATS/theft deterrent module issue under the dash.

Thoughts?

I meant to take off my signature. I've left off the supercharger for now. Instead running n/a with 30# SVO's -- to rule out any problems with the Versafueler and 65# Lucas/Delphi injectors (now removed).

[Edit] -- Also tested PCM grounds.

I've narrowed out everything I can think of...

If you're getting spark, then the optispark signalling is working correctly.

I'd look into the VATS bypass mod - maybe you need to do that?

Thanks for the response~

That's what I originally thought regarding the optispark. I have no opti signal DTC's. I'm actually running the Delteq, which seems to be very very picky on having a good optispark signal, so perhaps I can rule that out.

However, it's the same deal on the VATS. I thought VATS would kill the starter if that were the case, but the starter is working great. Fuel pump is priming without fail. As I said, I disabled VATS through the programming, but I'm not sure if that would be equivalent to the resistor bypass mod. I could easily try that next though -- good idea.

Thanks again.

Not sure about LT1s, but on the Gen III (LS1), VATS failure causes the exact same symptoms you describe - fuel injectors being cut off. At least, that's what I've read, and been told.

Cool. Well, not cool, but you know what I mean.

The LT1's have all sorts of VATS problems too, but it's just never been verified whether VATS cuts off fuel at the fuel pump, or if it cuts off fuel at the injector. Dead injectors seems to be a pretty rare occurrence, but perhaps that was always the case.

Despite not having any DTC's or a Security light, I agree that this does seem like a VATS or theft-deterrent module issue.

It just hit me -- I don't think the fuel pump was running while the engine was cranking. It primed at the first turn of the key, but I think it was dead after that. I'll double check tomorrow, but that also sounds like VATS. (Pretty sure the pump should be running while cranking, but it's been a while since this thing ran.)

Just thinking aloud.

Check to make sure the PCM is getting the low res pulse from the Opti. Without finding that signal, it shuts down the fuel pump and the injectors. Not sure why you wouldn't get the DTC code for the missing signal though.

If I knew what type of oscilloscope to buy, or how to use one, I'd install it into the freaking dashboard. As it stands, the only means I know of which to check the low-resolution pulse is the DTC, as you said.

I'll play with the VATS/TDR tonight, and I'll double-check the Optispark wiring up to the PCM...

UPDATE:

1) I bypassed the chip in my key by means of installing resisters in the wiring to the VATS module. Didn't change anything, not that I'm surprised, since I didn't have a flashing security light to begin with.

2) I got to the Theft Deterrent RELAY (not the module). I tested the relay itself, and it checks out. When installed in the car, I can feel it click on when I turn the key, so that would tell me that everything (including the TDM) is functioning as it should.

SOOooo, it would appear that my VATS system is working properly. I'm fresh out of ideas. I'll double-check the optispark wiring really quick, but that's really the only thing left in my mind which could cause dead injectors.

Any thoughts would be greatly appreciated~

Thought I'd update this one last time, just in case someone else is looking for answers. Found the problem:

After completely tearing out and removing everything I could imagine (VATS bypass, grounding the TDR, tearing out the Versafueler and swapping in hi-impedance injectors, three different PCM's, quadruple-checking injector wiring, noid lights, new optispark, taking datalogs, etc.)...

When checking for continuity from my optispark to the PCM pinouts, I found two wires didn't have continuity. Turns out my factory GM connector for the Optispark (to PCM) had two flattened terminals in it (female connector). Upon trying to straighten them with a pick, they snapped and fell out. As a quick test, I stuffed the connectors with aluminum foil, and she's up and running beautifully. Naturally, I still need to solder in a new connector.


Oddly, I had no DTC's, and I had spark, which is what threw me off for so long. I think this is due to the Delteq -- which intercepted my optispark signal before it made it to the bad connector to the PCM. Thus, I had spark when I otherwise wouldn't have with the stock setup. This, paired with no DTC's, led me to believe the PCM was getting proper signal from the Optispark, when it apparently wasn't. I could kick myself for not checking this sooner...

WHY WERE THERE NO TROUBLE CODES!!!! Crazy computers...


Thanks for everyone's help.

Thanks for the update. I could possibly be in the exact same situation regarding the GM connector....at least it's another thing for me to rule out just in case.