[stkshkr]

I know the fuel pressure is supposed to be set at 39.5 (40) at idle, but if I set that pressure at the regulator (fore pressure gauge) I show 48 on the passenger side rail (cab gauge). Is this normal?

 

[Throttle Jockey]

Just to clarify, base is set to 39.5 (40) PSI at idle with the vacuum reference removed from the FPR.

Pressure should be consant throughout the system so I suspect one of your gauges is out of whack.

 

[stkshkr]

vacuum reference removed from the FPR.

Didn't do that, thanks

 

[Throttle Jockey]

Reset the base FP and let us know what happens.

Once base FP is set the FP should decrease by 1 PSI for every 2 In./Hg. of vaccum applied to the regulator. For example, at 20 In./Hg. of vacuum at idle you should see about 30 PSI of FP.

When boost is applied to the FPR the FP should rise at a 1:1 ratio... in other words for evry pound of boost the FP should increase above the base FP by 1 PSI. If your truck makes 12 PSI of boost at WOT then you should see approximately 52 PSI of FP at WOT.

I don't think the pressure differential between your gauges is due to the improperly set base FP though, that may still be a gauge reading inaccurately.

 

[stkshkr]

After setting the correct way both gauges read the same. thanks again!