Hello,
quite recently I've been tuning Camaro with LS3, Camaro ZL1 with LSA, Corvete ZR1, all of them with upgraded injectors and I had the same problem - after ECM flash, on idle, I'm getting very high fuel pressure (around 450kPa), even when I command 350kPa for low/normal flow. It slowly descend to my commanded value, but sometimes it takes about 5 minutes until that I'm really on my commanded AFR, as injectors can't keep correct fuel amount under 1ms IPW. This problem disappear later on and after another engine start, it's pushing my commanded pressure. Anyway, it slows down idle/low load tuning, as I have to wait couple of minutes until fuel pressure settle down. Why it happens? It even differs from car to car and even the time for settling down is different.Sometimes it takes even 15 minutes to settle pressure down.
Another problem I discovered is that ID injectors sucks, when it comes to short pulse. It's just not possible to fine tune them. I'm getting spread +/-10% AFR on 0.5-0.8ms injector pulse width in the same MAF cell! In connection with above mentioned problem it renders them as waste of money as you expect to spend some more $ on their price and save something on dyno renting, but it's not the case when you spend 2 hours more to fine tune idle :bang head:
It happened 3 times and it really bothers me. Is there any trick to avoid this strange fuel pump behavior?
best regards, Fido