How does increasing the Fuel pressure affect the latencies, or does it?

 

"Technically" it doesn't...in a perfect world. However, as pressure increases against the pintle it takes longer to open due to the extra force applied. We're talking minute amounts though for smaller injector sizes, but once you start hitting the 1000cc range it can make a difference. Which is also why most large cc injectors use a disk style injector tip (Lucas usually) instead of a pintle type...lower latency time with the disk style.

 

would decreasing fuel pressure from 4 bar to 3.5 bar lean the idle on 1000cc injectors with the same latencies, does it also knock the fuel trims out?

 

Decreasing the base fuel pressure will affect the entire range.

 

It would richen idle because the actual latency would decrease.

 

spot on! Some how it went rich, have no idea why? Strange.