cold start rpm issue
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TECH Enthusiast
Joined: Jul 2010
Posts: 593
Likes: 29
From: Florida
cold start rpm issue Can someone look at this tune and tell me why when I do a cold start I have to keep my foot on the peddle at 1200 -1300 RPMS until it warms up to 120 degrees. than it will hold idle of 900rpm. Car is SD tuned, no 02 sensors.
C5R block
Callies dragon slayer 4.0" crank
Comp star rods (made by Callies)
Weseco pistons -8 cc
ETP 225cc heads , ported to 232cc by WCCH 2.12 intake 1,94 exhaust valves, .700" lift valve springs
Cam 255/257 .624/.624 lift on 111 +4
Super Victor intake
105mm TB with custom elbow
Stock rockers
LS7 lifters
ported oil pump
dual roller timing chain
Fuel
255L intank pump
60lb injectors
custome feed/return lines with regulator
Tranny
FLT level 6 with hardened input/output shafts
Yank SS3600 stall
SFI flexplate
C5R block
Callies dragon slayer 4.0" crank
Comp star rods (made by Callies)
Weseco pistons -8 cc
ETP 225cc heads , ported to 232cc by WCCH 2.12 intake 1,94 exhaust valves, .700" lift valve springs
Cam 255/257 .624/.624 lift on 111 +4
Super Victor intake
105mm TB with custom elbow
Stock rockers
LS7 lifters
ported oil pump
dual roller timing chain
Fuel
255L intank pump
60lb injectors
custome feed/return lines with regulator
Tranny
FLT level 6 with hardened input/output shafts
Yank SS3600 stall
SFI flexplate
Last edited by Tramminc; Jul 24, 2024 at 08:35 PM.
You are not logging any of the idle related PIDs that would be needed to properly diagnose your problem, but just a glance at the tune looks like your base running airflow is too low and idle spark is too high. With that size cam there is also the possibility that it will idle better if you utilize the idle alpha-n settings available in your OS. On a totally different subject, I'm pretty sure you will notice significant pressure drop if you log your WOT high rpm fuel pressure. Those extremely high VE numbers look like your oversize injectors are crutching a weak fuel pump.
