Escobar

iTrader: (27)

Hey guys, my Z has been having hot start issues. With the temp being so hot recently here in NC (95+) it has got much worse. It will only do it when I run it, and then let it sit for 30+ minutes. I have attached a video of what it does. Its like it starts right away but the rpm are at like 0 for a second or 2 like its just gonna stall, then it shoots up and idles fine...very strange. Im sure Nik at soho will figure it out, but I just figured I would post on here to see if any of you had experienced this and if you found a solution.

relevant fuel mods are RC 550 injectors, CJM state 0 fuel system, and walbro 255. When it was cool out, it had 0 issues, started like oem. Thanks!

Escobar

iTrader: (27)

bealljk

iTrader: (13)

your post-start enrichment and/or your prime pulse at higher temps is out...your tuner probably didnt spend much time in this area of your map.

Escobar

iTrader: (27)

ok, thanks. I'll see if he has checked that.

rcdash

iTrader: (18)

EDIT: Had it backwards! sorry.

Escobar

iTrader: (27)

I think thats exactly whats going on. Going to relay this, hopefully he can get it fixed. Other than that its running great. thanks

kilogram

iTrader: (1)

In my experience, it was the other way around. Evaporated fuel is vapor and still burns. I had it close- pretty much what OP's video shows. I added fuel and it got quite a bit worse (plus black smoke out the exhaust on startup). Pulling fuel helped. You should need less fuel when hot and more fuel when cold, since you have to compensate for port wall wetting when the engine is cold...

str8dum1

iTrader: (11)

ya you def wanna pull fuel for hot starts

bealljk

iTrader: (13)

Kilo has a pretty solid point with removing fuel. Something that hasnt been discussed is the lesser air volume being moved through the engine during start-up, especially on a turbo setup. Less air flow means less fuel required.

Esco, what are you tuning with? Osiris? or Haltech?

rcdash

iTrader: (18)

kilo and str8 are correct. I had it backwards for start up fueling; just checked my maps to confirm. Sorry. You need to pull fuel for both the prime pulse time and cranking injector time.

I do have an air temp correction that adds fuel to maintain stoich at idle as temp increases.

Escobar

iTrader: (27)

thanks for the good info here guys. I'll relay this to Nik. Bealljk, im using UpRev.