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So I have the car driving well and starting when warm with no issue. The issue is cold starts. It's a bitch to turn it over and fire when it's actually cold outside (like 50 degrees here...) So tomorrow my plan is to rerun the Base Running Airflow config from RussK in HPT and see what my desired airflow is. Which is calculated from what? It's a guesstimate right?
I have LTFT disable so I don't see LTITs... is there a way to enable them? Or is that tied to LTFT? Does it matter?
I need to check my IAC counts. I swapped from a FAST 102 to a NW 102 and need to see if I have more IAC headroom now. Seems like it just doesn't get enough air when cold. When I log tomorrow, I'll look at the IAC counts and play with the TB. The TPS is at .51v now, so I don't have a ton of room to open the blade. I can go to .6v? or is .55v the max TPS voltage for idle?
I did add some idle startup friction airflow. I added 7.5g across the board, because why the hell not. I've also added something like 3 to 5g of startup airflow by ECT. I've had it there and it didn't matter. The friction is new tho and might be useful.
Any other suggestions? I am running speed density. With hopefully some combination of open loop at idle and closed loop at cruise. I have it set that way and it appears to be behaving that way in my logs.
It almost seems like it can't burn the fuel effectively at cold temperatures. Here is my O/L EQ table settings. I have it so it runs richer at colder temps. Should I try leaning it out? As it warms to 160+ it idles out fine. I run around 70 kPa with my cam.
I'd try peeling back the EQ table enrichment but also
put some time into your cranking-VE table, which can
go neglected but needs a lot of help with a big cam.
You get a double whammy with both the VE being way
lower than table post-cam (so aim rich) and the high
cranking MAP (EQ table enrichment). There's no real
good way I know of to adjust the cranking table, other
than stitching the two together in Excel and trying to
fit the VE vs RPM trend at the low end, by eye and by
outcome (which outcome, can only be had over a bunch
of cold start cycles - tedious).
Thanks, Jimmy. I hadn't really messed with the cranking VE. But it was definitely way off from the VE table. I just manually massaged it and took about 5% off the EQ table enrichment in the lower temps. I'll see how that does.
So, it still won't start easily even with the cranking VE tuned a bit and friction airflow added. I had to open the TB blade to .57V to get IAC counts in the 40-50 range. So I figure I have the blade open enough for headroom...
One thing it's doing (although I didn't drive it around) was in Park with revs, it is very much lagged now. With my wideband I've got it idling pretty well when warm. So I think the A/F is pretty close at idle and off-idle. It wasn't doing this yesterday after driving it around. I had the TB open at .51V and it seemed to do okay. I wonder if the throttle cable is a little loose now with it being open another quarter turn to half turn?
Anyway, here are the logs. First is of the RussK idle config with it at .55V. I saw I needed more opening of the throttle blade. And opened it to .59V, but it seems engine vacuum pulled it back down to .57V and it settled there. The second is the same config but with me free revving it and it looking like dog ****.
Tune is also uploaded. I'm guessing adding all the additional airflow is making it unhappy. I plan to retune with the wideband tomorrow after messing around with all the airflow parameters. VE table still needs work anyway.
I wonder why the lag is there. I'll drive it tomorrow and log with the wideband with a different config file to see (but in park it should just free rev like mad). I had this issue before when I idle tuned the VE table. I did it by MAP pressure and sound, leaning out the table. Once I leaned it out to about what you see in the above, it had no throttle response - like it was starved for fuel. So I added some fuel back in.
However, I logged with my wideband yesterday and it told me to take out counts of between 3-6 in the idle areas. So I did. It ran fine and idled no problem. But today, trying to diagnose the cold start issue, the "feels like it has no fuel" thing came back at idle.
I'm so very close to getting this thing to behave. If I could just get the cold starts figured out and make it so it'll idle steady all the time (and not just when it feels like it), then I'd be happy.
Maybe. It just cranks and cranks and cranks. Then it catches after a while. Then it dies out before I can give it gas. But if I crank it again, it will fire the first time, but then it idles at 500 for a while and after about 5-10 secs it'll jump up to where it's supposed to. Sometimes. Sometimes it takes a couple of those false starts before it'll do that. If I give it gas, it almost always dies. Like it adds fuel but no airflow. Or airflow and no fuel.
Well, I've been playing around with a couple of things:
Spark Dwell Cranking Modifier - Couldn't find much on this, but it seems like I could adjust it to help?
Cranking/Start Timing - added 2 degrees across the range from stock. Stock timing is pretty low. My idle timing is 28 degrees vs 13 or so for the cranking timing. Should these be closer? I mean, this is a big cam with a lot of compression...
Afterstart Enrichment - reduced the decay delay, but left the numbers alone.
Will play with the Open Loop EQ a little bit more - probably needs even more fuel than what I have in there for cold temps... Or it might need less. I'll try both.
I'll see if that does anything.
Last edited by JakeFusion; Jan 31, 2015 at 01:13 AM.
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Cold Start Issues 
