Duts87ss

iTrader: (10)

I'm running a '165 ECM and with a modded AUJN 6E bin.

When I first try to start my car cold (about 65* here today) it was cranking for a while then just start and stumble. I had to feather the throttle to keep it running and then it would smooth out a bit (new 383 and still working on things; decided to get my starting issues solved and go from there).

Today I added some fuel in the Crank PW vs Coolant Temp at the area that matched the outside temp and the cell just above that. The car now fires up nice but then starts to stumble/sputter until I blip the throttle and get a good high idle.

Would I be right to continue to add a little more fuel to this area or do I need to move to a different area of the bin? I found a Startup Enrich vs Coolant Temp and also a Startup Enrich Decay vs Coolant Temp (may have quoted those incorrectly); would these be better places to start?

Seems to be lots of tables that cover the same issue just in slightly different ways.

Thanks.

RednGold86Z

iTrader: (1)

Startup Enrich vs Coolant Temp would be my first place to add fuel, if I were going for the quick fix.

Once the cranking happens and it fires up quickly, you won't get much benefit by adding much more (although you do need enough to get the first firings to be rich enough). I calibrate cranking, startup, and open loop enrichment - using a spare battery to preheat and power the wideband. I look for fire on the second revolution, a rich dip (if not emissions ~11-12:1, if for EURO4, 13.xx:1). I also don't change startup until the open loop steady state stuff is all where I want it (warm up at ~13.5:1 - but the table may need to say 12:1 or whatever (but with MAF it's a bit closer to actual=commanded), just get the actual output to be ~13.5:1 on a wideband). And don't change the open loop enrichment until the MAF tables are right. Then for start up enrichment, make sure it's enough to not lean out at all, and make the decay just right to keep the AFR on a nice path from 12:1 crank dip to the 13.5:1 open loop.

In order:
MAF Tables
Warmup Enrich (Open Loop AFR table)
Crank PWs
Startup Enrich
Startup Decay to make a desirable AFR trace from crank to open loop steady state AFR

When doing cold starts, if the AFR is in the 12-14:1 range, but it still stumbles, add some IAC to the Park Position table at the cold start temperatures. If you've got a big cam, you might also need to have the spark table at idle a little bit higher than stock, and also might need to add some startup spark advance.

While doing some of the cold starts, it's also advisable to do a few transient checks and improvements (Accel Enrich, Decel Enlean). It takes a while to get them perfect, but good enough can usually be had in 3-4 tries (depending on how radical it is).

Duts87ss

iTrader: (10)

I'm running a 268XFI cam; dont know if you'd call it big or not in a 383 (idles like stock, but at ~800rpm).

Looks like I need to take a look at the Warmup Enrich. Don't think I can make adjustments to the MAF table until I drive it more.

Thanks for the help.