I have a fiero with the 3800sc motor mated to an F23 manual transmission. Every time I try to go to an autocross with it, it stalls on the way. Otherwise it drives fine. There are two stall conditions (which I assume are related, but who knows), and I have those details below as well. I have a log and tune attached....I know the tune isn't good - I've been very cautiously trying to get the tune worked out, but I'm very new to tuning. I just got it to something I knew was safe so that I could drive it around.
Stall conditions:
Only occur after the engine is warmed up. I certainly assume that it's engine bay heat related. It stalls often when I am in DFCO and just push the clutch - not a huge surprise, and not a huge deal, just bump start it again, and it's good to go (that's the stall at 6:55 in the log). The real issue I have - occasionally it will stall under pretty much any load condition except WOT. It starts running real rough / bucking or it just shuts off for seemingly no reason. These ones don't like to restart until I open the decklid and let the heat out for a while, at which point, I have no issue again for a while. This stall happened at the end of the log, and it wouldn't restart for a while.
Car info:
3800sc (L67) from a 2000 Bonneville SSEI with an F23 manual transmission from a 2000-2002 Cavalier.
Aluminum flywheel / spec stage 3+ clutch
ZZP short stack intercooler
ZZP aluminum fuel rails
Walbro 255 fuel pump (same issues with a Deatchwerks DW300 pump)
3.2 supercharger pulley
60# fuel injectors (long story, but yes, I know they're oversized. I do have the stock injectors I can throw in if really needed.)
Intense stage 1x cam
Meziere electric water pump
No A/C, EGR, power steering, cat
My current theories:
ICM overheating - it's mounted on a different bracket than stock, so I have a heat sink I was going to try throwing on there. BUT the rpm seems to track fine in the log, so idk.
crank sensor - People say this should be replaced on these motors. But again, rpm is tracking fine.
IAC - I think the most likely at this point... it's still moving in the logs, and I can still hear it moving around when I'm priming the fuel system
Could be my shitty tune?
I've ruled out a vacuum / boost leak already - I was able to pressurize to 20psi without issue.
Any thoughts? I'd appreciate just about anything right now. My next step is to throw parts at it for the theories I have above (starting with the ICM since I already have parts) if I don't get any replies.
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