Cold Start Tuning After Cam Swap

[Nick Fly]

Is there anywhere I can look to get a few pointers on cold start tuning, specifically after a cam swap in an LC9 5.3 with an E38 ECU? Cam is a Comp Stage 1 Thumpr cam 218/229 duration, .541/.530 lift, 111 lobe separation. VE table seems to be dialed in, and after playing with idle settings to calm down surge in drive, I have lost my ability to cold start without peddling. According to the logs I have from before the idle adjustments my throttle blade would be around 28% open when cranking and now it goes straight to 5-6% as soon as cranking starts. If I hold the peddle down till the throttle blade registers in the mid to upper 20's then it will fire up. I attached a copy of my latest tune file. This tune seems to start fine once the vehicle is to operating temp and has been tested down to around 115 degrees Fahrenheit coolant temp at which point it also started up without peddling. The temps I am having issues starting at are around and below freezing. Any help will be greatly appreciated!

[Nick Fly]

Anybody?

[statesman]

Put your idle setting back to stock. Adjust fuel and spark to control surging.

[Nick Fly]

Could you be a little more specific about how to control fuel and spark to control surging? I've tried putting all idle settings back to stock and the truck still didn't start when cold without me peddling it. I had a spare throttle body laying around so I decided to drill a 1/4" (6.35mm) hole in the spare throttle body and tried that. Truck starts better but the surging came back much worse then it was originally. To cure surging again I reduced B1651 & B1652 till the surging was gone. B1651 ended up at 1.1 and B1652 ended up at .061. I can't say for sure that it will start great every time when coolant is cold until I've had a week or two of daily morning cold starts.
Is there not a setting that can be adjusted to set the throttle blade % open when cranking?

[izaks]

B1832 Cranking idle air

[izaks]

Also, log Throttle area with idle contribution to see the actual TB open %

[Nick Fly]

Thanks izaks, I'll give the throttle area with idle contribution pid a try! As for B1832, I've basically maxed that out in the -40 to 90 degrees F range and still didn't see any improvements. I was logging ETCTP% and MAF g/s to see what my airflow was doing while making adjustments to B1832, maybe these were not the pids to be watching??. Isn't ETCTP% the % actual that the throttle blade is open? When ETCTP% was in the mid to upper 20's while cranking, the truck would start. I usually had to peddle the gas in order to get numbers in the mid to upper 20's anytime the truck wad cranking and the coolant temp was below 70ish degrees F. Above 70ish degrees F, ETCTP% would read 26-28% open while cranking and the truck would fire up. If coolant was below 70ish degrees the ETCTP% would register 23% until the motor started cranking, then it would instantly drop down to 6% until I peddled the gas. It almost seemed like there was a setting that was keeping any changes made to B1832 from taking place. Any ideas if that's a possibility? I'll try logging a cold start up with the Throttle Area with Idle Contribution Pid and see what I see. I also attached a picture of my current B1832 settings.

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[izaks]

I only use V7, so can't read your file
ETCTP only shows */- 20 to 80 %
ACCEP will show 0 to 100 %
THRA_A will show real blade position
B1832 looks way too high

[Nick Fly]

Thanks for the help! I'll go back to stock settings for B1832 and try adjusting from there again. I'll try logging ACCEP and THRA_A while cranking and see what I'm working with. I'm wondering if I was adding too much air because I was assuming ETCTP was actual throttle blade open %. According to my wideband I was at 15-16:1 AFR while cranking for the first few seconds then it would go to 9-10:1 and still not start. Holding right around 13 degrees timing while cranking. If the truck ever cranked for more then 10 seconds or so without starting I'd have to hold the peddle to the floor to get it to fire. I believe holding the peddle to the floor while cranking makes the injectors stop firing but maybe I'm misunderstand "Flood Mode".

[Nick Fly]

I finally managed to get the truck to fire up decent in the cold, down to 20* F coolant temp, and still idle and drive almost as good as a stock cam. I attached a couple pictures, one is my cranking commanded fuel table, B0138, and the other is my Cranking Idle Air, B1832, table. I found the main things causing my issues were the MAF wasn't tuned correctly in the section from 0 to just below the lowest readings I ever saw when at idle, roughly 3000 Hertz. I tuned this section the same way i normally tune my MAF, but I noticed the lower section of the MAF table only gets touched when the engine is cranking over, at very low RPMs. So in order to tune the low sections of the table I had to only use readings that came from cranking the engine over. I did this and adjusted my MAF table accordingly a few times until my wideband was reading the same AFR, during crank, as I was commanding.
I also had to significantly reduce my B1832 table from the settings I have it at in post #7. The settings where too high at low coolant temps. See the above picture and the picture in this post to see the differences. Lastly, I set my cranking command fuel table to be leaner then it was set stock. Basically I set it to command 8:1-9:1 AFR when below 50 degrees F. My MAF table above 3000 Hertz was tuned while driving around. 3000 Hertz and below was set during cranking only. This, on average, increased my readings by 1.98 times what they were set originally. However, I don't believe these settings are the stock MAF settings. The truck was tuned by someone else prior to it coming to me.
Overall these adjustments helped my get the truck to start up right away when cold and when warm, and still idle and drive like a stock cam. 23647