fuel pressure vacuum

[1991vert]

everytime i set my FP to 40 with the vacuum off it somehow always gets messed up. am i supposed to run the car with the vacuum off?? or just set the FP with the vacuum off then put the vacuum line back on?

 

[whitehorseupnorth]

You need to pull the vac line off to set your FP. With the vac line off it will simulate WOT. Cause, at WOT there is no vaccum. Now, after setting the FP and then connecting the vac line, the FP will go down cause the vaccum from the engine will act against the spring inside the FPR. Pull vac line, set FP, reconnect vac line. Pretty simple..

 

[1991vert]

ya but then i'll check it again the next day with the vac off and it will read like
35 psi.

 

[1991vert]

also should i do this when the car is hot? or at initial start up (cold)?

 

[1990LXDropTop]

also should i do this when the car is hot? or at initial start up (cold)?

It is best to set it when the car is fully warmed up at normal operating temp.