Just curious as I didn't expect this.

Engine off fuel pump diagnostic jumped I adjusted the car to 43.5 psi. This is with the vacuum line on which I heard makes no difference when car is off.

Once warmed up to min of 80°c i pulled the vacuum line off and it jumps to 45psi.

Should I adjust it back to 43.5 psi while running?

 

no... you did it right. its really not that critical if youre using aftermarket injectors. in fact, it almost doesnt matter at all. whatever the injectors are doing at whatever pressure, the tune/tuner will compensate for. so if its 42, 43, 44, 44.7543, 45, whatever..... its fine. so long as its not a large base pressure difference then it will just run slightly lean or rich respectively..... or it may do nothing lol.

i say all that to say no, you dont need to do anything. you did it correctly.

 

Thx Cr-Rex.

I still have the 550s (which are now entered as 588) and now 1700s. Seems like it idles better already. I see no leaks and smell no fuel so it is time to re tune I guess.

 

The reason for the difference in pressure is most likely due to difference in voltage available to the fuel pump with the engine running vs. off. If you set pressure with the engine off, the best voltage you'll see at the pump is maybe 12.3~12.5V or so; with the engine running and a healthy alternator, that voltage should be somewhere between 13.7 ~ 14.5V. As CX said, nothing to worry about for small differences.

 

Thx Pete. That makes sense. I did have it on a charger, but it was no where near 14.5-14.7 as it is running. I am excited to get her going again. I am always paranoid with fuel fittings so I will feel uneasy for a few hundred miles, but all should be well. I may fine tune the idle today and hopefully get it in high 12 low 13 vs low to mid 12s.