VQ35 - Base timing out by 240 degrees after firmware update?

[knate240sx]

We had our 350Z plugin G4X ecu running our engine, then after doing the firmware update we ended up at 240 degrees BTDC to get it to run again. Previously it was just a few degrees to make it correct.

The 350Z crank pulley is a bit odd and has only 0 degrees, 15 degrees, and 20 degrees. At the dyno we weren't positive what the two marks were aside from zero, so we just used zero to set base timing. After just a couple hours of running the engine we found some scoring in the cylinder walls and ended up tearing down the engine. There is signs of detonation on most of the pistons on the intake side.

I trust the tune itself (done by Jason Oefelein), but I'm worried something may have been wrong with the base timing. 240 degrees seems like a very odd number to need after the firmware update. Also maybe our method of using 0 instead of the 15 or 20 degree mark may be less accurate?

1. Anyone else with a VQ35 have a need to crank the base timing so far off?

2. Is setting base timing to 240 degrees correct?

3. Is it possible using the 0 degrees mark on the crank pulley contributed to the timing being further off?

We are almost done with all of the rebuilding.. and I want to make sure we do not repeat the problem!

[Adamw]

No that doesnt sound right, the offset is near zero in all customer 350Z maps I have with 6.20 firmware.  If the engine has been apart, possibly the flywheel has been bolted on in the wrong position?  Some aftermarket flywheels dont have the location dowel.

[knate240sx]

21 minutes ago, Adamw said:

No that doesnt sound right, the offset is near zero in all customer 350Z maps I have with 6.20 firmware.  If the engine has been apart, possibly the flywheel has been bolted on in the wrong position?  Some aftermarket flywheels dont have the location dowel.

Thanks for the input Adam! That's the strange thing.. it started up fine with the older firmware in a factory untouched 350Z, then also worked with our engine so it's not a mechanical thing. We set our base timing on the dyno and it was single digits off, then Jason noticed we had older firmware and updated it. Then after doing that.. had to chase around with the base timing before finding marks on the crank pulley again and dialing into 240 degrees. I'm concerned this is related to the detonation, but not sure the best path to take with it.