VG30DETT warm crank issues after injectors swap
Posted: Fri Oct 08, 2021 2:50 am
BEFORE:
740cc Deatschwerks (370cc redrilled)
E85 for 8 years
Never had crank issues in all engine conditions from very cold (-10°C) to very hot (100°C)
CRANK_ENRICH 120 120 75 65 50 40 22 12 10 8 8 8 8 8 8 8
AFTER_START_ENRICH 200 200 200 140 125 110 90 70 55 45 35 30 30 30 30 30 (yes, 30 when high temp to counteract evaporation)
CRANK_TIMING 30 30 30 30 28 25 25 25 25 25 25 25 25 25 25 25 (yes 25° !)
K was in the range from 208 to 240 (auto adaptation) depending on ethanol % (from ~62 to ~76%)
Latency 1120us
NOW:
750cc 12 holes
Had to adapt:
_the fuel map a bit
_K is in the range from 184 to 196 at the moment (78% ethanol)_auto-adapt
CRANK_ENRICH deeply decreased (the old values prevented me from starting ...). These injectors throw out more more fuel when cranking compared to the previous ones.I suspect a vaporization issue.
Runs perfectly fine (cruising, WOT, etc ...)
At the moment:
CRANK_ENRICH 60 60 48 34 24 16 10 9 8 8 7 6 6 5 5 5
AFTER_START_ENRICH 160 160 140 115 100 85 70 60 50 40 30 20 10 10 10 10
CRANK_TIMING 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
I decreased a lot CRANK_TIMING to be in a better condition when cranking
Latency from 850 to 1120us, makes no change in warm cranking
Symptoms:
Cold crank from 10°C to 50°C: no problem (1second starter @10°C, 2seconds @50°C)
Mid warm crank from 30°C to 60°C: no problem (2s starter)
Warm crank @80°C or @90°C (even after having stopped 5mins): no problem
Warm crank from 60°C to 90°C after sitting half an hour ==> does not start. Here, this is hit&miss behaviour. Eventually, on the second attempt, it may start, or pumping the throttle will make it start after a while.
Cold crank phase 1 (perfect): crank pulse OK
Cold crank phase 2 (perfect): after start OK
Warm crank phase 1: crank pulse OK
To sum-up, the quick switch to the TP-based fuel map is a nightmare for me, the pulse is so big that it kills the RPM. I don't remember what controls the duration of the use of CRANK_ENRICH table (RPM threshold ? Time based ?), one way would be to use the crank table longer to delay the switch to the fuel map. Hope you got my concerns.
740cc Deatschwerks (370cc redrilled)
E85 for 8 years
Never had crank issues in all engine conditions from very cold (-10°C) to very hot (100°C)
CRANK_ENRICH 120 120 75 65 50 40 22 12 10 8 8 8 8 8 8 8
AFTER_START_ENRICH 200 200 200 140 125 110 90 70 55 45 35 30 30 30 30 30 (yes, 30 when high temp to counteract evaporation)
CRANK_TIMING 30 30 30 30 28 25 25 25 25 25 25 25 25 25 25 25 (yes 25° !)
K was in the range from 208 to 240 (auto adaptation) depending on ethanol % (from ~62 to ~76%)
Latency 1120us
NOW:
750cc 12 holes
Had to adapt:
_the fuel map a bit
_K is in the range from 184 to 196 at the moment (78% ethanol)_auto-adapt
CRANK_ENRICH deeply decreased (the old values prevented me from starting ...). These injectors throw out more more fuel when cranking compared to the previous ones.I suspect a vaporization issue.
Runs perfectly fine (cruising, WOT, etc ...)
At the moment:
CRANK_ENRICH 60 60 48 34 24 16 10 9 8 8 7 6 6 5 5 5
AFTER_START_ENRICH 160 160 140 115 100 85 70 60 50 40 30 20 10 10 10 10
CRANK_TIMING 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
I decreased a lot CRANK_TIMING to be in a better condition when cranking
Latency from 850 to 1120us, makes no change in warm cranking
Symptoms:
Cold crank from 10°C to 50°C: no problem (1second starter @10°C, 2seconds @50°C)
Mid warm crank from 30°C to 60°C: no problem (2s starter)
Warm crank @80°C or @90°C (even after having stopped 5mins): no problem
Warm crank from 60°C to 90°C after sitting half an hour ==> does not start. Here, this is hit&miss behaviour. Eventually, on the second attempt, it may start, or pumping the throttle will make it start after a while.
Cold crank phase 1 (perfect): crank pulse OK
Cold crank phase 2 (perfect): after start OK
Warm crank phase 1: crank pulse OK
To sum-up, the quick switch to the TP-based fuel map is a nightmare for me, the pulse is so big that it kills the RPM. I don't remember what controls the duration of the use of CRANK_ENRICH table (RPM threshold ? Time based ?), one way would be to use the crank table longer to delay the switch to the fuel map. Hope you got my concerns.