3 Attachment(s)
Cold Start Stall After Injector Swap
Hi All,
This past offseason I swapped my truck from Snake Eater Performance 1000's to SEP Pro Series 1000 (genuine Bosch). Overall I'm happy with how my speed density tuning has been going and the truck is within about 4% everywhere once warm other than a few areas but one of the issues I've had since is worse cold starting. The truck is running a flex fuel tune and I'm normally running pump E85 but did the same with the old injectors. The old injectors would fire the truck up in the middle of Winter no problem, now I'm having issues with a cold start on a 60F ambient cold start.
Generally the engine will stall at least once, sometimes twice. After it does fire and start running, I normally have to give it a minute before I shift into gear (increase load) or it will die again. After the cold start, it starts normally. My initial assumption is that it's something around either not having cranking/idle VE dialed back in, incorrect injector data inputted, or something to do with how I fail the MAF as opposed to before.
Cranking/Idle VE is difficult because my wideband resets and goes through it's heater cycle as soon as you start to crank so that data is missed during a cold start (are all widebands like this?).
As far as injector data, I halved the flow vs pressure and set it to the 400kpa setting across the board (same as my last injectors) as I have a boost referenced FPR. Because of this I doubled the stoich AFR. The offset vs volts for LS3 was a direct copy paste but my short pulse correction was not. Not only does HPT not allow you to put your exact numbers in here but the neither provided scale from SEP lines up with the columns in my calibration so these were interpolated. Maybe something there?
With the new injectors I also wanted to fix a historical issue I had where I was failing the MAF incorrectly which would lead to me having to start the engine multiple times after flashing a calibration until it tripped the code and started running right. That issue seems to be fixed now.
Looking at the two starts in the log file, I don't see a ton of difference between the first start where the engine stalled, and the second start when it stayed running. One of the main things I see is ignition timing difference between the two. It was running high teens, low 20's on the first start, second was low teens into single digits. LMK if anything else sticks out to you.
[/ATTACH]Attachment 148524
