Success! - 400Pontiac, MSD Distributor, 6AL

[krisr]

Last interval has help a lot! I've been out driving for about 3 hours tonight using autotune and a little MSTweak. I just need to enrich the high load areas a bit and lean out the cruise parts and I'm done. I sitll need to tweak the timing a little but the engine seems to be running pretty good now.

Yeah I found it helped alot too to get more accurate static timing.

Have you just been working on mapping the VE table or started on the enrichment side of things yet? One thing i've been trying to get right is the injector opening time. I found the default 1.0ms seems to be ok, but there is an equation in the tuning fuel & air forum that shows how to mathematicallly work out your opening time with pulsewidth and amount of squirts... I calculated about 1.1ms should get me in the ballpark, but I cannot swap from 2 to 4 squirts and not have it want to die on me.

Ohwell it turns out I have a bad alternator, the minute the fans cut in and start blowing hot air over it, it will discharge until the car stops. I know it's not the fans as I can disable the fans afterward and it will still discharge about 11.8V-12.2V, i.e. run off battery. I let it sit for about 4 hours, fire it up again and bingo, 14.4V.... A new diode pack may help but i'm not so sure as i've replaced the regulator twice...

God this hobby is fun!!!

[busta9876]

I run in 4 squirt mode, going to 2 wont even start...i still havnt figured out why...

cranking pulse should have nothing to do with 2 or 4 squirt, because it squirts all 8 injectors at every ignition event right?

i've just been tuning VE table for right now, i want to get everything + or - 5% correction before i start on other stuff...

i'm down to 1% change every 30 ignition events on EGO, seems to smooth table rather well...MSTweak does a much better job then autotune, and it lets me tune the areas autotune won.t

[krisr]

cranking pulse should have nothing to do with 2 or 4 squirt, because it squirts all 8 injectors at every ignition event right?

Correct. I set my cranking pulse width as per the manual. My REQ_FUEL was 12.5ms being a 400" engine with 42lb injectors. I set my cranking p/w at -40°F to 11.0ms and set 170°F at 2.8ms. It will start every time without any issues!

I must have a go at MSTweak soon. I have plenty of datalogs at home, just never tried it out yet.

[ChevelleFan]

I must have a go at MSTweak soon. I have plenty of datalogs at home, just never tried it out yet.

Datalogs are only valid against the VE table they were created with. IE-- if you take a log, run it through MSTweak and it changes your VE table, that datalog wont be valid for future iterations through MSTweak.

-Dave