Rolling Thunder

So I just completed the 0411 ECM swap in my Trans Am and of course it won't start. Using a timing light I found the ignition timing was firing at 0 degrees TDC which explains why it doesn't want to start. Using the EFI live scan tool I confirmed that was no error the PCM is actually calling for 0 degrees of advance.

However, after looking through the tune file I see no reason for the ECM to call for 0 degrees of timing? According to the "Spark Timing When Cranking" table it should be calling for like 13 degrees of advance? I even tried changing the "Minimum Spark Advance", which according to EFI live's description is the absolute minimum timing that the PCM will ever allow, to 10 degrees and it's still calling for 0 degrees of timing? The tune is essentially a stock l-31 tune with the exception of things like the VATS being disabled. Any ideas as to what is going on here?

EagleMark

Your tun file on EFI Live website shows:
Look at {B5915} Minimum Spark Advance. Stock is 10 degrees, in yours it's -15...

Other then that it looks fine. Could be a wiring issue?

Rolling Thunder

So I double checked my minimum spark advance table and it seems to be set to 10 advanced? The stock calibration I believe was -15?

As far as wiring is concerned, there's no possibility I can absolutely 100% exclude. Today, I confirmed at least the ignition control module/coil wiring is definitely correct.

Looking at it from the PCM's stand point though my log shows the PCM calling for 0 degrees of advance. However, the calibrations are set such that 0 degrees of advance shouldn't even be possible? Could it be the PCM is just blown? The PCM I bought was a remanned unit from NAPA and while they sell quality stuff again I cannot absolutely 100% confirm that its good either.

EagleMark

Even if it were 0 degree timing it should still start. Is it getting fuel? Did you turn off security/Vats? That will disable fuel.

Rolling Thunder

Yup definitely have fuel. Injectors are firing confirmed with a noid light plus there's liquid fuel even on the plugs themselves. The plugs are definitely firing as well. Pulled a few out, grounded the body of the spark plug, and cranked it over. You can see a nice healthy spark. I doubt it's a mixture problem (at least as far as what the PCM has control of) since it's essentially a stock l-31 with a stock l-31 tune. I really do not believe a sbc could run with 0 degrees of advance much less start especially in the cold. I would love to eliminate that as a possibility by advancing the timing to something reasonable but the PCM does not seem to want to respond to calibration changes.

onegonewild

Did you ever resolve this issue? can you update?