Simple fuel pressure question

[QuickWE4]

Usually, when I set my fp, I start the car, let it warm up until it's at normal temp, and then set my fp. I recently reset it because I thought it was a little rich for the new chip.

Anyway, drove the car around yesterday for about an hour. Came back and checked fp again - it was a little low. So, I reset it to 42 line off.

Now, going forward, is it always better to check fp after driving the car or is it ok to simply start it and let it warm up for 15 minutes? Why the variance? Vacuum different after driving for an hour?

Rich

 

[The Radius Kid]

You should let the car warm up to set your base fuel pressure.When you first set it right after you start the car,your charging system is on high charge,putting out more voltage.The pump is still running cooler,ignition is running hotter,etc.
It's not a bad way to get the fuel in the ballpark,but set the final adjustment[vacuum off,vacuum line plugged],after the car has warmed up and all systems have settled in.

 

[QuickWE4]

ok, that makes sense. My fp is always high for a while until the car has been driven, then it settles in.

Thanks - I was just curious about the variation.

Rich

 

[GNsQuick]

set mine last night to make some DS runs was on 42# when I left and was on #36 when I got back!