Warm start issues

[Tigre_loco]

Hey guys I am having some issues with a car I'm working on. I'm hoping you all may be able to give me some help.

Car is a 2000 C5 with an ls3 stroker and A&A blower kit on the car. Tune is a 2 bar SD OS. Running an FTI streetweeper cam. Ls6 intake w/ factory throttle body and FIC 1300cc injectors with their provided data.

I just finished the build and the car starts up and idles well with the very rough and baseline adjustments I've made to the file until I can begin actually tuning and making adjustments based on the car's needs. The issue is I am running into a warm start problem and I'd prefer to get it ironed out before proceeding.

The car starts up and idles really well and will idle up to full operating temp with no issues until I shut the car off and attempt to restart. I have finally narrowed it down to a specific temperature of 174 degrees and above. Once the car reaches this temp it will not restart, not even attempt to, it will only crank over. Throttle input makes no difference. Once the temp drops below the car will start up just fine once again. *** As I was attempting to get a new data log to share here the car randomly started while at 185ish ECT twice then returned back to no start condition***

I have tried messing with the various air, fuel and spark tables in that temperature range to no avail. I was hoping you guys could guide towards a solution.

What specific parameters would you like to see in a log file in order to troubleshoot this issue?? I've got an LM2 wideband on the car but it doesn't seem to be behaving for consistent readings during startup even with alternate 12v supply. I will be installing a new AEM 30-0333 wideband later this evening hopefully allowing for better AFR readings.

I have attached my tune file and various logs.

I appreciate any and all help.Thanks in advance.

Car starts before 174.hpl
No start 2.hpl
No start.hpl
Started at 185 F 2.hpl
SD tuning failed starts at 174 F idle VE 1.10.hpt

[Tigre_loco]

Bump

[dermotw]

Your Friction Airflow Initial and Startup Airflow (under Idle >> Airflow..) I would expect to be more than that, they look like standard, it's not going to fire up that easily with that, even cold, imho. My Friction Airflow Initial is double yours, & you can see my mods in the sig. Also the Friction Airflow Delay, usually its more with a cam, mine is 25...

-D

EDIT: Should have said, looks like you are logging most things, but you could add idle desired airflow and idle startup airflow, there is also idle cracker a/f and idle follower a/f, I didn't notice if you already had those logged. Also, the IAC count is high (you have IAC?), and the LTIT also (suggesting the idle is somewhat 'off').

[Tigre_loco]

I was out of town for a few weeks so hadn't had a chance to mess with this much. I made some adjustments to the tables you recommended Dermotw. No change. I didn't have any issues firing the car up cold but with the changes you described it did start up better. The car is DBW so no IAC.

It's just odd that the car will start until 174*F has been hit and after that the car no longer will start until either the coolant temp sensor is unplugged defaulting to -38* or until the coolant temps drop below 174*.

Makes me think there is something specific to that temperature in a table somewhere which is holding me up. I will begin dialing in the VE and Idle airflow over the next few days to ensure that is correct. I have refrained from doing that until I can figure out the issue at hand as I don't think it is related to either of those tables being significantly out of adjustment. But maybe I am wrong.

[dermotw]

I know it's an obvious thing, but you have looked at the DTC's when it happens I suppose? No odd DTCs? And imho you are right about the tables, even if they were miles off it would still fire up initially at least...

[Tigre_loco]

I know it's an obvious thing, but you have looked at the DTC's when it happens I suppose? No odd DTCs? And imho you are right about the tables, even if they were miles off it would still fire up initially at least...

Yeah the only DTC was for the MAF to ensure it is failed with the 2 Bar SD I hadn't deleted the code yet.

[Tigre_loco]

Bump for further suggestions. At a loss here. Tried to get some VE tuning in last night only to get stranded while attempting to load the updated file then having to wait for the car to cool off below 174*F before being able to start again and drive home.